Showing papers in "Philosophical Transactions of the Royal Society B in 1969"

Organization of the Primate Retina: Light Microscopy

Abstract: The structure of the human, but mainly of the rhesus monkey, retina as examined by Golgi-staining techniques is described and interpreted on evidence from both light and electron microscopy. One type of rod bipolar cell and two types of cone bipolar cell are recognized. The rod bipolar is exclusively connected to rods. The midget bipolar is postsynaptic to only one cone but each cone is also presynaptic to a diffuse cone (flat) bipolar. Such flat bipolar cells are in synaptic relationship with about seven cones. No other bipolar cell types have been found. The brush bipolar of Polyak is interpreted as probably a distorted rod bipolar, while Polyak's centrifugal bipolar is a misinterpretation of the morphology of diffuse amacrine cells. When presumptive centrifugal bipolars were observed they appeared to be a developmental stage of amacrine cells. In the outer plexiform layer two types of horizontal cell have been defined. Each type of horizontal cell has a single axon and two kinds of horizontal cell axon terminals are recognized. In the inner plexiform layer there are two main classes of amacrine cells: the stratified amacrines and the diffuse amacrines. Each class of amacrine has a wide variety of shapes. Polyak's midget ganglion cell is confirmed and his five other kinds of ganglion cell are classified into diffuse and stratified ganglion cells according to the level at which their dendrites branch within the inner plexiform layer. A fuller summary is given by the diagram and in the legend of figure 98, p. 174. A new type of midget bipolar is described in the Appendix (p. 177).

Studies on the Larval Structure and Metamorphosis of Balanus balanoides (L.)

Abstract: Balanus balanoides (L.) has seven planktonic larval stages. The first six are nauplius larvae while the seventh is the cypris larva. The cypris larva is specially adapted to locate a suitable place for settlement. The structure of the nauplius larva is basically similar to that of the nauplii of other crustacean groups. During successive nauplius stages, however, the simplicity of its anatomy is progressively obscured by the development of the cypris organ systems. All the organ systems do not differentiate simultaneously, but development is closely related to the time at which the organ must start to function. The three pairs of nauplius appendages, antennules, antennae and mandibles, are used in locomotion and the latter two pairs are also used in feeding. The six pairs of cypris thoracic swimming appendages, and the first and second maxillae with their associated ganglia and muscles, develop from groups of ectoteloblasts and mesoteloblasts in the ventral thoracic region of the nauplius. The compound eyes develop as outgrowths of the lateral lobes of the brain. The paired cement glands develop pre-orally. The end sacs of the adult maxillary glands develop as cavities in the somites of the second maxillary segment. The cypris antennules develop within the nauplius antennules but differentiation of their intrinsic musculature is delayed until after the nauplius-cypris moult. The various muscles of the cypris carapace are fully formed by the time of the nauplius-cypris moult. During, and after, the moult, a number of morphological and histological changes occur. The antennae and mandibles regress, the intrinsic musculature and cement ducts of the antennules complete their development. At the same time all the nauplius muscles and the antennal glands histolyse. Until these changes are completed the cypris larva is probably unable to settle, and thus to initiate the changes leading to the completion of metamorphosis. Rudimentary adult mandibles, and first and second maxillae are incorporated into the oral cone. After the moult the digestive region of the nauplius mid-gut epithelium and other epithelial cells are sloughed off into the gut lumen and digested together with the remains of the food ingested by the nauplius. The oesophagus and hind gut are now closed and the cypris larva does not feed. The adult digestive glands develop at the junction of the oesophagus and mid-gut. In the cypris the nauplius frontal filaments are associated with the compound eyes and connected to the brain via the optic ganglia. The median eye is apparently unchanged. Paired antennular ganglia are present. Those neurons, which innervated nauplius structures which have histolysed, also degenerate. The nauplius antennal glands degenerate at the nauplius-cypris moult; the maxillary glands are probably the functional organs of ionic regulation in the cypris as well as in the adult. The conspicuous multinucleate oil cells of the cypris are probably a food reserve. The paired masses of yellow cells in the carapace, originate in the antennae of the nauplius and migrate into the carapace after the moult. During the 24 h between settlement and the moult to the young adult, all the cypris muscles histolyse. The muscles break up spontaneously into short fragments which are then ingested by phagocytic haemocytes. There is widespread histolysis of neurons in the nervous system and further cells are sloughed from the gut epithelium. The adult mantle muscles, which are recognizable in the free swimming cypris larva, complete their differentiation, and in the few hours preceding the cypris-adult moult the adult thoracic muscles develop. The nervous system assumes its adult form and adult neurons differentiate from cells which had previously lain dormant in the nervous system. The compound eyes, frontal filaments and optic ganglia degenerate, but the median eye persists apparently unchanged. The yellow cells disperse, but their function is unknown. The cement glands persist in the adult, but the adult gland cells differentiate from cells aroung the collecting duct of the larval gland while the larval cement gland cells histolyse. The median eye persists, but in the newly moulted adult the three components separate giving rise to the three adult photoreceptors: a pair of pigmented ocelli and a median unpigmented photoreceptor. Shortly after the moult the young adult resumes feeding. This study has shown that metamorphosis in Balanus balanoides must be thought of in terms of the change from the nauplius through the cypris to the young adult and not just as the changes taking place between settlement and ecdysis to the young adult.

On the Structure of the Antennular Attachment Organ of the Cypris Larva of Balanus balanoides (L.)

Abstract: The third segment of the antennule of the cypris larva of Balanus balanoides is modified as an attachment organ with a disk by which the cyprid attaches to submerged surfaces. The attachment disk is covered with a felt of fine cuticular villi. Opening on to the disk are terminal branches of the cement duct, numerous glands and an array of sensory hairs. The sensory structures are arthropod scolopidia with the dendrites giving rise to cilia which, distally, change to distal sensory processes. It is suggested that the cuticular hairs situated in invaginations of the cuticle around the margin of the disk function as position receptors and that the two setae lying away from the cuticle of the segment are mechanoreceptors. Three of the scolopidia have structures suiting them for chemoreception; the distal sensory processes are exposed to the exterior at the tip of the hair. Two of these hairs are positioned at the margin and one at the centre of the disk. The fourth segment, which arises from the side of the attachment organ, is packed with sensory cell processes which are associated with setae arising at the distal end; its movements are controlled by a single muscle from the third segment. A suction mechanism of adhesion is precluded as there are no structures which could effect or release suction beneath the disk. The disk could act as an adhesive pad, with the cuticular villi increasing its surface area and the antennular glands possibly secreting a viscous substance. The presence of chemoreceptors on the attachment organ indicates that a chemosensory mechanism could operate during the gregarious behaviour of settling cyprids.

Structural Changes, Related to Reproduction, in the Hypothalamus and in the Pars Tuberalis of the Rhesus Monkey. Part I. The Hypothalamus. Part II. The Pars Tuberalis

Abstract: Certain cells lining a circumscribed area of the III ventricle of the rhesus monkey differ from those cells which constitute the characteristic ependymal lining of the brain. The specialized cells studied comprise a number of types which differ in their structure, ultrastructure and staining affinities; all demonstrate features which are generally associated with active secretion and/or absorption. A group of such cells, which form a limited area of the latero-ventral walls of the anterior hypothalamus, have long processes which extend to the walls of the blood vessels in the median eminence. The evidence indicates that many of these cells, here described as Type B or tanycyte cells, secrete their products into the primary capillary network of the pituitary portal system. Another group of cells, here described as Type C and $C'$ cells are found in a slightly more posterior position lining the floor of the ventricle; as yet there are no indications that these may secrete into blood vessels in the median eminence. Some of the specialized cells lining the III ventricle (Types B and C') showed changes in relation to reproductive activity: No such changes were observed in Type C cells nor in the characteristic ependymal cells (Type A) found elsewhere. Studies on normal and experimental male and female monkeys showed that Type B tanycyte cells differed in males and females and altered during the menstrual cycle in the female. Following ovariectomy these cells showed regressive changes but returned to a normal appearance after a single injection of oestradiol. In view of the close spatial relationship of the tanycyte ependyma to cells of the pars tuberalis it was interesting to note that pars tuberalis cells also altered in relation to the menstrual cycle. The evidence presented accords with the view that certain cells which line the III ventricle of the brain and have prolongations extending to pituitary blood vessels, thus linking the cerebrospinal fluid and the blood system in the region of the pituitary, may play a role in the regulation of pituitary function and thereby constitute an important neuro-endocrine system.

The Effects of Altitudinal Variation in Ethiopian Populations

Abstract: A study has been made of three neighbouring populations living at 1500, 3000 and 3700 m in the northern Simien of Ethiopia. The environments of these populations not only differ in many climatic elements, but also probably in nutritional factors and exposure to infections. The growth and physique of the people vary with altitude and the lowlanders (at 1500 m) tend to have a more linear body build. Differences in chest dimensions can be related to functional differences in respiratory physiology, since the highland groups, both male and female, have larger forced expiratory volumes and forced vital capacities as compared with the lowlanders. The relationships between these measures of respiratory function and age, stature and weight also tend to be dependent on altitude, but in all the Ethiopian groups there is a closer relationship between body weight and respiratory capacity than in other populations. This distinctiveness is probably due to the characteristics of Ethiopian physique. A slight polycythaemia and elevated packed cell volume are evident in the highland groups but, unexpectedly, there is some evidence that at least at the time of the expedition the haemoglobin concentrations were lower. The highlanders also show a raised systolic blood pressure. Blood-group and demographic data suggest that the various populations are probably genetically very similar, and the findings are discussed in terms of physiological and developmental adaptability.

The Vegetation of the Solomon Islands

Abstract: The Solomon Islands are entirely clothed in tropical rain forest except for small areas of probably anthropogenous grasslands and heaths which occur in regions with a seasonal climate. The main features of the vegetation are described and related to the exceptionally wet climate of the archipelago. The extensive areas which carry thickets of small trees and climber tangles instead of high forest are thought due to the combined influence of man, earthquake, landslip and cyclone. Many species are shown to have wide ecological amplitudes.

Electron microscopy of the glio-vascular organization of the brain of octopus

Abstract: The glio-vascular organization of the octopus brain has been studied by light and electron microscopy. The structure of the walls of the blood vessels has been described. Two types of neuroglia can be recognized, the fibrous and protoplasmic glia; also enigmatic dark cells. Most blood vessels in the neuropil are surrounded by extracellular zones containing collagen. These zones give off glio-vascular tunnels (strands) that penetrate the neuropil in a complex network. The extracellular zones and tunnels contain in addition to collagen, smooth muscle cells and fibrocytes. Glial processes surround the extracellular zones and incompletely partition them from the neuropil. The small neuronal perikarya have no glial folds around them. The medium-size cells have thin glial sheets or finger processes related to their surfaces, which may indent the cells to form small trophospongia. The large neurons of the suboesophageal lobe have complex glial sheaths interspersed with extracellular channels. Both penetrate the neurons to form complex trophospongia. A new form of extracellular material has been observed in these extracellular channels. The occurrence of trophospongia in vertebrate and invertebrate neurons may be correlated with the absence of dendrites. Special problems discussed include the nature of the trophospongial function, the question of fluid-filled extracellular zones and their possible function as lymph channels, and the presence in some of them of haemocyanin molecules identical with those in the blood vessels. Perhaps of special importance is the observation that the lobes of the octopus brain are permeated with extracellular tunnels containing smooth muscle fibres, but it still needs to be determined whether or not the muscle cells in the tunnels of the neuropil actively contract and massage the neuropil to facilitate metabolic and other exchanges.

The marine algae of the Solomon Islands and their place in biotic reefs

Abstract: The Royal Society Expedition to the Solomon Islands aimed at examining the biogeographical relationships between these islands -and other island systems of the western tropical Pacific. The marine party also studied intertidal and reef ecology. Comprehensive collections of benthic marine algae were made at the main localities visited (Florida Islands, north-west and south-east Guadalcanal, Matiu Island off the north coast and Batuona and Ulukoro Islands off the south coast of New Georgia, Banika Island in the Russell Islands, and south-east Gizo Island). Additional small collections were obtained from Kolombangara and the north coast of San Cristobal. Habitat notes accompanied each collection and preliminary determinations were made in the field where possible. General ecological observations on the reefs included profiles selected after a preliminary survey of an area. Such profiles (see below) indicate the general situation but are not based on detailed transect work; restricted time and the great variation in distribution of organisms over the reef surface (especially in the moat) rendered isolated detailed transects of limited value. The marine algal flora of the Solomon Islands has been one of the least known in tropical regions. Setchell (I935) recorded nine species from Malaita Island and also several taxa from Sikaiana Island (in the Stewart Islands, north-east of Malaita Island) and from Bellona Island, south of the Solomon Islands. Levring (i960) recorded a number of species from Rennell Island, near Bellona Island. Otherwise there are only a few scattered records in taxonomic monographs. TAXONOMIC ACCOUNT Taxonomic studies are well advanced and it appears that about 220 species of Chlorophyta and Rhodophyta can be credited to the Solomon Islands. The Cyanophyta are well represented also, as free-living forms, epiphytes and within the encrusting corallines, but have not yet been determined. Only a few species appear to be undescribed, but two of these (in the Ceramiaceae and Rhodomelaceae of the Rhodophyta) are probably generically distinct. A full account of the known marine algae of the Solomon Islands will be published later.

The Biomorphology of Solomon Islands Shore with a Discussion of Zoning Patterns and Ecological Terminology

Abstract: The descriptive ecology of the Solomon Islands shores will be dealt with in a series of Reports from the marine party of the 1965 BSIP Expedition of the Royal Society, now in preparation This paper is a preliminary attempt to sketch out a biological classification of the shores of those Islands, and to set up some form of descriptive methodology in the light of the special character of the shores observed, in relation to existing zoning systems It must be followed by extended Reports on the adaptive ecology and the distribution of life forms in particular habitats

The Complex of Ficus deltoidea; A Recent Invasion of the Sunda Shelf

Abstract: A detailed account of the complex of F. deltoidea Jack and F. oleaefolia King is given in order that its problems may be taken up in the field. Thirteen varieties of F. deltoidea are distinguished, eight of F. oleaefolia . The link between them is F. deltoidea v. motleyana (Miq.) Corner. Clear evolutionary trends to very small figs and leaves and to dichotomous venation supply the evidence for the conclusions that the most reduced state F. deltoidea v. angustifolia (Miq.) Corner is the most widely spread; that the complex advanced into the lowland and mountain forests of the Sunda Shelf from Borneo; that the original connexion was with the ancestors of ser. Podosyceae Corner in the Philippines; that the large seed is a primitive retention; that the complex did not evolve through vicarious disruption of a widespread ancestor; and that, as a recent development of Ficus , possibly still in the making, it represents most clearly the manner of speciation and geographical distribution prevalent in the genus. New taxa: F. deltoidea Jack var. kinabaluensis (Stapf) Corner, F. oleaefolia King var. linearifolia Corner and var, valida Corner.

Geomorphology of the Solomon Islands Coral Reefs

Abstract: The opportunity to study the coral reefs of the Solomon Islands was valuable for two reasons. First, the Melanesian region has been remarkably neglected by reef workers. To the south-west, the Great Barrier Reef Expedition of 1928-9 provided a basis for understanding Australian reefs; the Snellius Expedition explored those of Indonesia; the Japanese and more recently the Americans have studied the high islands of Micronesia, especially Guam and Saipan; and much recent work has been carried out on the atolls of the Carolines and Marshalls. Within Melanesia itself, the Gatala Aquarium in Noumea and the Singer-Polignac Expedition have begun work on the New Caledonian reefs; the Noona Dan Expedition visited the Bismarck Archipelago and Rennell Island; and some prewar studies were made in Fiji and the New Hebrides. Almost no work at all had been done in the Solomon Islands before 1965, with one notable exception.

The Architecture of the Accessory Reproductive Glands of The Desert Locust IV. Fine Structure of the Glandular Epithelium

Abstract: The male desert locust, Schistocerca gregaria, has two masses of thin glands, each mass containing 16 glands. The glands in each mass are arranged in a precise manner, which is a mirror image of the arrangement to be found in the other gland mass. They produce secretions which participate in the production of the spermatophore and most of its contents during mating. The fine structure of these glands is described in detail on the basis of an electron-microscope study of sectioned glands and their secretions. It is revealed that the characteristics of the glandular epithelia and their corresponding secretions lead to the division of the accessory glands into nine distinct types. This finding strengthens the recent division of the glands into nine types based on histological, histochemical, and phase-contrast features. One gland produces a proteinaceous, crystalline secretion (gland 1), three types of glands produce a minutely fibrous secretion (glands 2 and 4, and 'homogeneous' glands), three other gland types produce a globular secretion (glands 6, 11 and 12), and one gland type has a lipoid secretion (gland 3). Gland 16, the functional seminal vesicle, does not produce a recognizable secretion. The cytoplasmic organelles that are concerned in the secretory process, and the manner in which their development varies with each gland type, are discussed.

The Glio-Vascular System of Cephalopods

Abstract: The branches of the cerebral arteries run to the centre of each lobe of the brain and from there radiate outwards. The arteries are lined by endothelial cells, surrounded by pericytes. Outside these are large extracellular spaces containing collagen. These spaces continue as a system of ‘glio-vascular’ channels among the tissues. These channels contain collagen and other extracellular material and nuclei belonging probably to muscle cells and fibroblasts. This system permeates the neuropil and in the cell layers provides wrappings for the perikarya. The channels and extracellular material form tunnels of ‘trophospongium’ within the neuronal cytoplasm. Glial fingers also penetrate into these channels but are not well seen by light microscopy. The system of spaces among the tissues communicates with an elaborate set of branching ‘lymphoid9 channels. These collect into veins either in the membrane around the brain or at the centre of the optic lobe. The veins discharge to the pharyngo-ophthalmic vein and the brain is thus provided with a venous system partly isolated from the main haemocoele. The true neuroglia cells are of two types. The protoplasmic glia cells have much-branched processes, especially in the neuropil. They have abundant end-feet attached to the outside of the perivascular channels and to the glio-vascular strands. They occur in the cell layers and their processes probably penetrate the neurons. The fibrous glia have very long processes, mostly smooth and with little branching. The processes run in bundles accompanying the main tracts of nerve fibres in the neuropil and extending into the cell layers.

Insect Distribution Patterns in the Solomon Islands

Abstract: Among insects in the Solomon Islands some endemic taxa show restricted island distributions. An account of these is given and they are related to a continuous process of expansion of new taxa from the West and replacement of older ones. This is accompanied by speciation and subspeciation and shifts in habitat. The results of ecological studies are summarized which illustrate the types of selection operating at different stages of the cycle. The importance of island area and distance from other islands is emphasized.

Histology and Fine Structure of the Pre-Optic Nucleus and Hypothalamic Tracts of the European Eel Anguilla anguilla L.

Abstract: The pre-optic nucleus and hypothalamic tracts of intact and hypophysectomized specimens of the European eel Anguilla anguilla L. have been studied in situ and by optical and electron microscopy. The in situ technique reveals a hitherto unsuspected degree of segregation of the neurosecretory axons which form up to five discrete tracts having separate origins and following distinct paths before converging, at the level of the anterior margin of the pituitary, to form a median tract. The structure of the pre-optic neurons, as revealed by several different techniques, is described and it is shown that their synthetic poles, identified by a prominent cap of endoplasmic reticulum, are precisely orientated towards the third ventricle and are separated from it by, at most, two or three layers of ependymal cells. Electron microscopy shows that the secretory products lie mainly in the axonal ends of the cells though in Bouin-fixed, wax-embedded material the entire perikaryon stains with neurosecretory dyes and this, and their proximity to the third ventricle, gives the impression that they secrete into the latter, as well as centripetally. This may well be so, but from the work described below it seems more likely that these neurons receive nutrients, or stimuli, or both, from the third ventricle. Two types of pre-optic neurons, separable by structural features as well as by the size of the elementary granules they contain have been identified; these probably give rise to two of the fibre types identified in the neurohypophysis of the eel by Knowles & Vollrath. Aggregations of neurosecretion, common in the fish pre-optic nucleus, and also, much rarer, colloid vesicles, are described and discussed.

Geomorphology of the Marovo Elevated Barrier Reef, New Georgia

Abstract: W. M. Davis considered that ‘none of the elevated reefs of the Solomon Islands is more remarkable than the emerged barrier reef which skirts the north-eastern side of the long island of New Georgia’ (Davis 1928, pp. 397-398), and this reef was one of the main objects of geomorphic work during the Royal Society Expedition to the British Solomon Islands. Davis did not visit the Solomons and based his discussion entirely on charts, and apart from the Admiralty Pilot , the Pacific Islands Handbook , and brief mention in the publications of the Geological Survey of the British Solomon Islands, the New Georgia reefs have remained entirely unstudied. The Marine Party of the Expedition visited New Georgia three times: first, from 2 to 9 August 1965, concentrating on the northern Marovo Lagoon; secondly, from 26 August to 8 September, when the biologists returned to the same area, and geomorphic work was extended south to the southern end of Japuchajomo and north to Lumaliha; and thirdly, from 14 October to 18 November, when M. V. Maroro was engaged in echosounding and bottom sampling with the writer and Dr P. E. Gibbs in Marovo , Kolo, Togavai and Gerasi Lagoons. A brief visit was also paid by the whole marine party to Ulukoro and Batuona Islands, Wickham Anchorage, en route to Gizo, on 3 September. This paper reports on studies of reef geomorphology carried out during these visits, and includes studies made by diving at Matiu Island in collaboration with Dr S. A. Wainwright. The sedimentological and bottom fauna studies carried out during the coring, dredging and grab-sampling programmes on the lagoon floor will be reported separately.

Investigations on the duiker (Sylvicapra grimmia) and its blood protozoa in central Africa.

Abstract: The research is based on material collected from 110 duikers ( Sylvicapra grimmia ) in Malawi, Rhodesia and Zambia. The habitats of the duiker in Central Africa are described and also various other aspects of ecology. The feeding and management of the animal is discussed, fostering youngsters on to goats being found more successful than rearing on the bottle. The technique of splenectomy is described. Acepromazine was used for sedation and intravenous thiopentone sodium for anaesthesia, the latter being maintained with ether when necessary. Plasmodium (Vinckeia) brucei and P. (V.) cephalophi were rediscovered in Malawi. P. (V.) brucei is described in detail from blood films and compared with P. (V.) cephalophi . The organism was transmitted to another duiker by blood inoculations. The course of the blood infection in a naturally infected splenectomized antelope is described. Attempts to find the vector and exoerythrocytic stages were unsuccessful. Theileri -like trypanosomes, i.e. Trypanosoma (Megatrypanum) spp.—were frequently found in duikers. The parasites have been recorded from at least 23 different species of ruminants. The organisms from duikers are easily cultured on artificial media but difficult to maintain. Attempts at transmission by blood inoculation produced inconclusive results and the vector of the duiker parasite was not discovered. It is possible that the duiker is the host of more than one species of Trypanosoma (Megatrypanum) . Detailed morphological studies, however, of the trypanosomes using biometrical methods failed to reveal any clear-cut statistical difference between the parasites in different duikers from different localities or between the parasites from duikers, cattle and other ruminants. It is considered preferable at this stage not to include T (M.) ingens, T (M.) tragelaphi and T. (M.) cephalophi in the synonymy of the older species T (M.) theileri , although they may conveniently be referred to as ‘ theileri -like trypanosomes’. A brief description of other trypanosomes found in the duiker is given and other records are mentioned. Just under 2 % of the duikers in this survey were found to be infected with piroplasms, probably Cytauxzoon sylvicaprae . A detailed description of the organisms is given. Several duikers in Rhodesia and Malawi were found infected with Sarcocystis . The duiker appears to be a new host record for this parasite. The spores of the organism, as seen in blood films, presumably released from ruptured cysts, are described. The parasite may be a new species of Sarcocystis .

Aspects of polychaete ecology with particular reference to commensalism

Abstract: (Plates 69 and 70) In his monograph of the Polychaeta in the Fauna of India series, Fauvel (I953) records about 450 species that are to be found in the waters around India but he believed that this number represented only about one-half of the total. Day's recent work (Day i967) dealing with the polychaete fauna of Southern Africa has listed about 750 species from this region. It seems probable that a similarly large number of polychaete species will be recorded eventually from the central West Pacific region since a large proportion of the species recorded from Southern Africa and around India are known to be distributed throughout the Indo-West Pacific area, extending from the Red Sea to Japan and Eastern Australia. In many of these species a circumtropical distribution is apparent. In view of the fact that the polychaete fauna of the central West Pacific region is still very incompletely known, the Royal Society Expedition to the Solomon Islands in 1965 offered a unique opportunity for obtaining material from this area. The bulk of the material collected by the author comes from the littoral zone of the coral reefs as well as from the sediments of the more sheltered shores. However, in conjunction with Dr D. R. Stoddart's physiographic survey of the Marovo Lagoon complex in the eastern part of New Georgia, the author carried out a dredging survey, comprising about 40 stations in depths of less than 35 m, and many interesting shallow-water invertebrates were obtained. The polychaete fauna of the Solomon Islands appears to be rich and so far only a relatively small number of the species have been identified. Most of these species have proved to be well-known Indo-Pacific forms but some have posed some interesting problems from the taxonomic and biogeographical viewpoints. A systematic account of the poly- chaete fauna of the Solomon Islands is planned for publication in the future. This paper is a preliminary report on some aspects of the work that was carried out in the Solomon Islands. The first section is a description of the polychaete faunas of some littoral habitats. The second section presents some observations on those polychaetes that

Floristic relationships between New Caledonia and the Solomon Islands

Abstract: New Caledonia and the Solomon Islands are compared briefly as to location, size, climate, and other physical features. Possibly 585 seed-plant genera known from the Solomon-Santa Cruz groups are indigenous there, and 692 similarly may be indigenous in New Caledonia. Unknown from New Caledonia are 272 of the Solomons genera and unreported from the Solomons are 379 of the New Caledonian genera. Thus only 313 genera, or 32.5%, of the 964 total genera are common to both archipelagoes. It is suggested that the relatively smaller generic flora of the Solomons reflects the more limited botanical exploration of the Solomons as well as the greater variability of climate, substrate, and vegetation types of New Caledonia. Also New Caledonia is believed to have a much older, more relict flora than the Solomons, as indicated by the numerous conifers and primitive angiosperms (four genera of which are primitively vesselless). The far greater generic endemism (perhaps 94 genera or 13.5%) of New Caledonia as compared with the Solomons (5 genera or 0.86%) is explained by the much greater isolation in space and time of New Caledonia from other land masses. New Caledonia has its closest botanical relationships with coastal Queensland and New Guinea, with which it shares 474 and 482 genera respectively. Its floristic affinities are less with New Zealand and the Outer Melanesian Arc. The Solomons, on the other hand, have their closest botanical ties with New Guinea through New Britain and New Ireland. At least 572, or almost 98%, of the 585 genera recorded from the Solomons are represented also in New Guinea. As with the fauna, however, the Solomons flora is much attenuated, lacking many of the characteristic New Guinea genera, especially those of the montane and alpine regions. The break between the Solomon Islands and the Santa Cruz Islands is much greater than that between New Guinea and the Bismarcks and between the Bismarcks and the Solomons.

The habits and habitats of the opisthobranch molluscs of the British Solomon Islands

Abstract: Often bizarre in shape and gaudily coloured, the opisthobranchs of the tropical IndoPacific have always been attractive subjects for the specialist worker and for writers of popular natural history. There is certainly no lack of papers describing their anatomy and systematics (Marcus & Burch (1965) give a fairly full bibliography), but only in those by Risbec (1928 a, b , 1951, 1953) are there descriptions of where or how they live and his statements are brief and rather vague. I collected opisthobranchs so as to record them for the British Solomon Islands for the first time and, whenever possible, I noted their habits and habitats. My observations on gut contents are rather scanty as I did not wish to damage any of the few specimens of each species collected. From an examination of ten different types of reef formation I discovered that opisthobranchs are common in only two places; (1) the crest of a semi-exposed reef where algae occur in pools, and (2) the flat of a sheltered or semi-sheltered reef. At each of these sites several distinct habitats can be distinguished. Unfortunately my recognition of these habitats is not supported by strong numerical evidence as none of the 55 species occurred in large numbers.

Geography of the Flowering Plants

Abstract: The phanerogam flora of the Solomon Islands resembles that of Malesia, but has fewer families, genera and species. A number of lines of evidence indicate that it is not a recent, immigrant flora, and has not arrived by long-distance dispersal. The implication to be drawn from phanerogam distributions in Melanesia is that there have been stronger land connexions within the region and with Malesia in the past. The poverty of the Solomons flora is partly explicable by incomplete immigration from Malesia. There is also evidence for chance extinctions within the Group such as could follow from the continually changing land-sea boundaries. In its present form with a uniform flora with few local endemics, yet disjunctions to neighbouring island groups, the archipelago may well represent a ‘land-bridge’. Surprisingly there is no evidence of extensive species radiation in the Solomons despite gross geological viscissitudes; this is contrary to expectations based on temperate floras and suggests that flowering plant evolution in the tropics may be very slow. Further knowledge of the dates of land-sea changes in Melanesia should allow a time-scale to be set on the evolution of individual species.

Patterns in the distribution of Melanesian land Mollusca

Abstract: Melanesia is important in any discussion concerned with the distribution of terrestrial Mollusca in the Pacific region, as a zone exhibiting an intermingling of faunas derived from different geographical areas. Along the chain of islands constituting Melanesia these faunal elements exhibit changing patterns consistent with island hopping across water gaps. Yet the numbers of species of Mollusca on these islands show a positive correlation with the size of the individual islands (figure 19) and not, as might be expected, with the distance of particular taxonomic groups from centres of dispersal. Variations in this pattern can be attributed to differences in the isolation of islands, ecological diversity and the paucity of collecting in many areas. It should be realized that the distributional patterns recorded for any particular taxon must reflect the frequency and density of collecting and the inadequacies of the systematics of the group, besides biological attributes of the taxon and the island. The limitations should not distract, however, from attempts to analyse the available information, instead they must serve as a guide to the difficulties involved.

The Fauna of Rennell and Bellona, Solomon Islands

Abstract: The present survey of the fauna of Rennell and Bellona Islands is based on personal acquaintance during three visits to Rennell, over 2 months’ duration in all, as well as on published records. These are first and foremost to be found in The natural history of Rennell Island, British Solomon Island , published by Danish Science Press on behalf of the University of Copenhagen and the British Museum (Natural History) London. Vol. 1 (1958) contains five introductory papers and seven papers on the vertebrate animals, vol. 2 (1959) and vol. 4 (1962) two additional papers on the vertebrates and 26 papers on invertebrates, and vol. 3 (1960) contains six papers on botany and geology. Another 18 papers, which will be published in 1968 in vol. 5, and are based on recent expeditions to Rennell (see below) have also been utilized in the present survey. Literature referring to early visits to Rennell and Bellona (before 1951) is listed by Wolff (1955 a). The most comprehensive of these papers are those on birds (Mayr 1931 a, b), reptiles (Slevin 1934), ants (Wheeler 1934), vascular plants (Fosberg 1940), and geology (Stanley 1929).

Orchids of the Solomon Islands

Abstract: This paper deals very much with generalizations rather than statistically usable facts. The science of orchidology has never attracted many workers, never as many as, say, the fungi or the grasses or the ferns. The orchidologists there are and have been and probably will be are mostly involved with describing new species and relegating to synonymy those species described by their past and present colleagues! There has been very, very little geographical and phylogenetic speculation in the orchids by orchidologists and in our present state of incomplete knowledge, generalizations are all that can be aimed for. Altogether 350 gatherings of orchids were made during the Expedition and most of these are represented by dried, i.e. pressed, herbarium specimens. For the information of nonbotanists, as with the herbarium specimens of other plant families, the great majority of orchids had more than one specimen collected, and the duplicates have been distributed to Herbaria in all parts of the world. In fact at least 17 Herbaria have received some specimens of orchids collected on the Expedition. The usual policy is to distribute only those that are fully identified—otherwise somebody may describe it as new! The great majority of the 350 collected were also preserved in liquid, either as whole plants if these were very small or a sample of the flowers of the larger species. In addition, 130 living plants were sent back to Kew for cultivation such as Sarcochilus moorei , which has such a short flowering period, the flowering probably being brought on by a sudden drop in temperature as has been recorded in some Malayan species. About half of these are represented by pressed specimens made at the time of collection, but the remainder were collected only as living plants as they were not flowering at the time. As they flower at Kew they are identified and specimens made. Many have also been photographed and several painted by the official Kew artist for the collection of orchid drawings housed at Kew.

Earthworms of the British Solomon Islands Protectorate

Abstract: Fifteen species of earthworms are known from the British Solomon Islands. Of these, 11 are referred to the megascolecid genus Pheretima and one to each of the megascolecid genera Pontodrilus, Dichogaster and Ocnerodrilus, and the glossoscolecid genus Pontoscolex. Four species of Pheretima are known only from the Solomons; all other species are widely distributed peregrine forms. Reasons are given for regarding Pheretima bifida Gates and P. lavangguana Gates as synonyms of P. solomonis (Beddard). Pontodrilus matsushimensis Iizuka is recorded from the intertidal zone of Solomons shores. It is also known from the shores of other Pacific islands and is probably dispersed by ocean currents. Within the Solomons there is no apparent relationship between the distribution of earthworms and contemporary geographic barriers. The small number of species, predominance of peregrines associated with man, and lack of evidence of endemism and adaptive radiation indicate that most, if not all, the species (except P. matsushimensis) have probably been introduced by man. Geological evidence does not favour former land connexions between the Solomons and any of the adjacent large land masses. The character of the earthworm fauna indicates that any such connexions are most unlikely to have existed. The earthworm fauna is examined in relation to various biogeographic theories, including the equilibrium theory of MacArthur & Wilson (1963, 1967). It is concluded that the earthworms of the Solomons have not attained a state of equilibrium in the sense of these authors' theory, and that factors not considered in the equilibrium theory are primarily responsible for the present constitution of the earthworm fauna. Some aspects of the ecology of the intertidal earthworm P. matsushimensis are discussed.

Some soils of the British Solomon Islands Protectorate

Abstract: Soils were studied on the islands of Guadalcanal, Kolombangara, Santa Isabel, San Jorge, and San Cristobal, mainly under tropical rain forest in mountainous inland regions. The climate of the Solomon Islands is characterized by high temperatures and humidity, copious rain and a high proportion of cloudy days, with little seasonal variation except in the rainfall of the central coastal region of northern Gaudalcanal. In the areas studied soils on stable sites are deep, and intensely weathered and leached. On steep slopes soils are shallow and unstable, with much colluvial rock debris. Most soils are strongly acid to acid (pH 3 to 5) clays and have very low plant nutrient contents. On soils from basic igneous and ultrabasic metamorphic rocks weathering and leaching have resulted in loss of virtually all of the more readily weatherable constituents and extreme relative accumulation of oxides, principally of aluminium, iron and titanium. Rendzinas are found on recently exposed coral limestone, but older limestone areas have strongly leached soils similar to those on basic igneous rocks. The Solomons soils are related to similar soils in Hawaii, Western Samoa, New Caledonia, New Zealand, Australia, the West Indies and south-east Asia. In general the most strongly leached Solomons soils have reached a stage of degradation beyond that of similar soils described from other regions. There is apparently an almost closed organic cycle of nutrient turn-over under rain forest, with most of the available plant nutrients concentrated in organic-matter-enriched surface soil horizons and with little contribution to plant growth from underlying mineral horizons. There is little evidence of close relationships between soils and vegetation, except in soils derived from serpentine which have a forest dominated by Casuarina papuana. Large-scale destruction by fire of Casuarina forest on soils from serpentine has resulted in loss of surface horizons by erosion, failure of the forest to regenerate, and formation of laterite on the bare soil surface. Small-scale destruction of forest for native gardens appears to have little long-term effect on soils or vegetation. 'Soil' animals are usually confined to logs and other above-ground habitats and are rare in the soil, apparently due to the extreme wetness and probably partial anaerobiosis of below-ground habitats.

Some notes on the climate of the British Solomon Islands

Abstract: The Solomons are among the wettest regions of the globe. Among twenty-four stations having 7 years or more of complete years’ records to 1963, only four had a mean annual rainfall below 100 in. Pending full analysis of records from a scattered, but growing, network of climatological stations taking upper-air observations in the south-west Pacific, it seems that there is a basic easterly flow of air, with wave-type perturbations, and surface vortical circulations having a generally westerly movement. South of the equatorial perturbation belt, and dominating weather over the Solomons during the larger part of the year, are the south-easterly variables, or ‘trades’, themselves marked by zones of convergence that may be related to passage of meridional fronts along the root-zone of the south-easterlies, far south of the Solomons. These may be responsible for the spells of wet weather that occur during the south-easterly months, during some of which quite exceptional conditions of cloudiness and precipitation occur. The Royal Society Expedition encountered one such in 1965; more than 120 in. of rain were recorded in 2 weeks at a gauge on the southern side of Guadalcanal; severe landslip and flood damage occurred quite widely in the Solomons and adjacent areas

Some Geological Notes on Areas Visited by the Royal Society Expedition to the British Solomon Islands, 1965

Abstract: The British Solomon Islands consist of a double chain of elongated islands in the form of a bow whose apices lie in the single islands of Bougainville in the west and San Cristobal in the east. The length of the main island chain is 650 miles, if Bougainville, which is part of Australian New Guinea, is included. The Royal Society 1965 Expedition field parties visited eight different areas selected to give the widest variation of environment. These areas are well scattered throughout the main islands of the Solomons and are underlain by representatives of all the major geological rock units. To relate the geology of the areas visited to the general geology, a summary is given below. Figure 1 shows the areas visited. On all the main islands in the Solomons except the New Georgia group, the lowest unit of the geological succession is a basalt or basaltic andesite.

Ficus sect. adenosperma

Abstract: The structure, distribution and classification of the twenty species of sect. Adenosperma are reviewed. The section is centred on New Guinea where nineteen species occur and F. megalophylla persists as the pachycaul relic. The section relates with sect. Sycocarpus subsect. Auriculisperma of the Solomon Islands and connects with the origin of sect. Ficus through the Philippine species F. pseudopalma and F. rivularis along the Sararanga-front of the Melanesian Foreland. The most widespread species are among the most advanced. They show the usual trend in Ficus from the stout pachycaul with large multibracteate fig to the leptocaul with lanceolate leaf and small fig, along with the development of cauliflory and geocarpy. There is no evidence to suggest that the species evolved through vicariism, and the two series Amphigenae and Hypogenae run almost identical courses from Celebes to New Hebrides. Two new species are described from New Guinea, F. pilulifera and F. suffruticosa.

Sand cays of eastern Guadalcanal

Abstract: The cays and reefs of eastern Guadalcanal have never been described, and are hardly referred to in the literature. Brenchley (1873, pp. 274-276) visited Marau Sound in H.M.S. Curacoa in September 1865, but made no observations of value; Guppy unfortunately did not call there; and the work of the Geological Survey of the British Solomon Islands has been confined to the high islands. There is brief mention of some of the cays in the Pacific Islands Pilot , but in effect the cays of east Guadalcanal were unknown at the time of this study. With the exception of studies by Umbgrove (1928, 1947) and Kuenen (1933) in the East Indies, studies of reef islands have largely been carried out on open-ocean atolls or on barrier reefs. Island morphology in these areas has been shown to be dependent on barrier reef geometry and wave energy, the most diverse island types being found in barrier reef areas with a wide range of energy conditions (Steers 1929, 1937; Spender 1930; Stoddart 1965). It had been expected that the Melanesian reefs, with their diverse topography, would show a similar range of island form. Several workers have also attached great importance to a presumed recent negative shift of sea level, both in originating many surface features of reefs and in permitting island accumulation on abnormally high reef flats (Gardiner 1931; Sewell 1935; Cloud 1954). It is doubtful whether such a negative shift in sea level did occur, at least in the Holocene (Shepard et al . 1967), and it was thus of interest to study Melanesian reef islands formed in an area of recent tectonic uplift, local emergence simulating conditions once thought to be more general.