Showing papers in "American Midland Naturalist in 1946"

Observations on the biology of the snail Lymnaea stagtiahs appressa during twenty generations in laboratory culture.

Abstract: During the course of the last one hundred years various notes and papers have appeared presenting observations on the life history and culture of numerous lymnaeids; in the last two decades the emphasis of the research on this subject has been placed increasingly on an experimental investigation of the factors governing growth. A review of the results of these investigations indicates that Lymnaea is well adapted to serve as a dependable, easily handled, normal, healthy, experimental mollusc of conveniently small size, of short life cycle, and available in quantity and in various stages of development throughout the year. This genus is endowed with further desirable qualities: many of its species occur over a wide geographic range, are fairly constant in form, have been1 popular laboratory material for over eighty years (certain species such as L. stagnalis have been studied more intensively ecologically, physiologically, histologically, morphologically than any other basommatophoran pulmonate), and are probably tlhe highest form of animal life in the evolutionary series in which self-fertilization occurs (Baily, 1931). In the parasitological field, these snails are also important as vectors of parasites of man, domestic animals, wild game and fish. In this connection, KrulI (1931) in a paper on the importance of laboratory-raised snails in helminthology, writes: "Life history studies are rapidly occupying the attention of the helminthologists throughout the world, and this phase will soon be on a par with taxonomic investigations in the group. The snail is almost indispensable in life history work on trematodes." In an effort to develop further the potentialities of Lymnaea as an experimental gastropod, this paper attempts, through the integrated contributions of numerous earlier researchers and by additional original investigation on L. stagnalis appressa Say to present a simple, inexpensive, reliable method for culturing it in quantity. Observations on the life history of L. s. appressa cultured in this laboratory for twenty generations over a period of six years are also reported. This snail, besides its excellent response to laboratory culture, has the added characteristic advantage of possessing a relatively thin semitransparent shell which permits inspection of many of the internal organs in the living, undisturbed animal. Certain environmental conditions have been described in the literature as improving growth and fertility in lymnaeids. Boycott (1936) in studying the native habitats of freshwater Mollusca in Britain, came to the conclusion that "the more important features of favorable habitats are (1) cleanliness of

The Growth of the Slider Turtle, Pseudemys Scripta Elegans

Abstract: The naturalist's fragmentary knowledge of the habits and life history of turtles has been only feebly augmented since the days of Agassiz. The modern herpetologist has no thorough knowledge of the ecology of any one species and little or no information is available on the bionomics of many others. In 1939 a long term program designed to collect data on the turtles of Illinois was initiated at Carbondale, in the southern part of the state, and data have been accumulated on many phases of the life histories of the more abundant species. In an attempt to obtain data on growth, longevity, attainment of sexual maturity, migration, home ranges, and associated problems, approximately 3000 turtles have been marked and released, and about 500 of these have been recovered at least once. Several hundred stomachs and gonads have been preserved for the study of food and for the analysis of the sex cycle. The present report, concerning growth in the slider turtle Pseudernys scripta elegans Wied, represents the first segment of a long term program on the bionomics of this form. The primary purposes of this paper are: (a) to present and evaluate techniques for studying absolute growth in turtles and (b) to summarize our knowledge of the growth of the turtle named in southern Illinois.

Cenozoic and Mesozoic Bryophytes of North America

Abstract: The greatest taxonomic problem confronting those who study fossil mosses and hepatics is a paradoxical one-instead of being lumped into form-genera, they have been "identified" with a misleading precision and exactitude. Tlle reasons for this anomalous situation are not hard to find. In the first place, fossil bryophytes are so very rare that they have been described one by one, usually in comparison with living genera, without much reference to earlier descriptions. In the second place, many specimens have been described by nonbryologists who are naturally unaware of modern systematic trends in bryophytes. Furthermore, most of the bryophyte fossils have been named on a local flora basis-the person identifying them has been influenced consciously or unconsciously by the species now inhabiting the region from which the fossil came, in choosing a name. However, as Chaney and many others have shown, there has been a great change in the distribution of floras during Cenozoic times, and one must be familiar with tropical genera as well as temperate ones in order to identify correctly many fossils of Tertiary age.

Incidence of worm parasites in Minnesota Mustelidae and host lists and keys to North American species.

Abstract: The parasitological examination of various species of wild North American Mustelidae, until recently, has been limited to a few animals or has been incidental to other investigations such as food habit studies. Much of the information pertaining to this group of host species has resulted from the investigations carried on in the interest of fur farmers. Some additional parasitological data have been obtained by the examination of animals which have died in zoological gardens. The present report is based on the necropsy findings for 547 mustelids of eight species. The known helminth parasites of North American Mustelidae are listed under their hosts, and keys for their determination are appended.

Studies in the Trigonocarpales. Part II. Taxonomic Problems and a Revision of the Genus Pachytesta

Abstract: Paleozoic seeds are usually found as isolated, detached organs, and the difficulty of determining relationships has long been recognized. In isolated specimens known with structure preserved general relationships to leaf and stem types are generally proposed based on anatomical similarities. Even then such seeds are generally referred to distinct organ genera. A recurrent problem exists when isolated seeds known only from superficial characters or insufficient structural features are assigned to the same genus as those known with structure well preserved. The basis of this difficulty lies in the extreme variability which may be obtained by a single type of seed depending upon the nature and state of its preservation. For instance, in the radiospermic seed Pachytesta vera, the anatomy of which was described in considerable detail in Part I (Hoskins and Cross, 1946), it is possible to find several preservation forms. Some of these are complete seeds but others may have lost varying amounts of outer tissue. They may be altered, flattened, or variously changed in form. If the surface appears essentially smooth, with longitudinal striations occurring irregularlv, it is of the Neuropterocarpus-type shown diagrammatically in figure 49. These striations may be an expression of sclerenchyma strands in the outer tissue, of vascular bundles within the outer fleshy layer, or as shrinkage phenomena. A second type may be either completely or partially decorticated with its surface marked by numerous more or less strongly developed ridges of the Holcospermum-type as shown in figures 49 and 55. These ridges may varv widely in origin. They may be an expression of the surface of a much ribbed, strong, stony layer either showing through a compressed or shrunken layer of outer fleshy tissue, or the actual surface of the stony layer if all external tissues have been lost; or they may represent the vascular system of the nucellus either as casts or molds of the inner or outer surface of the mature nucellus as in figure 55.

The Role of Wood Anatomy in Phylogeny

Abstract: During the past three decades, plant anatomists have established a number of lines of phylogenetic specialization in the structures of the stele. Just as the taxonomists have worked out certain trends in the evolution of the flowerfor example, the change from spiral to the cyclic arrangement of the floral organs, from free floral parts to fused floral organs, from hypogyny to epigyny, etc.-so morphologists have described the following lines of anatomical specialization: 1. The prostostele is more primitive than the siphonostele or the dictyostele (i.e., eustele of Brebner) (Jeffrey, 1897, 1917). 2. In the Angiosperms, the woody stem of trees and shrubs is more primitive than that of herbaceous plants (Eames, 1911; Sinnott and Bailey, 1914, 1922; Jeffrey and Torrey, 1921, 1921a). 3. The vessel element with scalariform perforation plates appeared in plants before the vessel member with a single opening in the perforation plates (Jeffrey, 1917; Bailey and Tupper, 1918; Frost, 1930, 1930a). 4. Among the vessel elements with scalariform perforation plates, the tvpe with numerous bars and narrow openings is more primitive than the type in which there are few bars separating wide openings or perforations (Frost, 1930a). 5. The vessel elements which are long, small in diameter, and angular in cross-section preceded those which are short, broad, and circular in crosssectional outline (Bailey and Tupper, 1918; Bailey, 1920; Frost, 1930). 6. Vessel elements with long, sloping end-walls are more primitive than those with end-walls which are transverse (Bailey and Tupper, 1918; Frost, 1930, 1930a). 7. The phylogenetic order of the several types of pitting on the side walls of the vessels is scalariform, transitional, opposite, and finally alternate (Bailev and Tupper, 1918; Frost, 1930, 1931). 8. The type of vessel arrangement in which the pores occur singly throughout the wood (i.e., solitary pores) is less advanced than the various aggregate groupings, such as pore multiples, pore clusters, and pore chains (Frost, uinpublished data). 9. The diffuse-porous condition is more primitive than the ring-porous state (Frost, 1930; Gilbert, 1940). 10. Evolution has proceeded from tracheids to fiber-tracheids to libriform wood fibers (Jeffrey, 1917; Bailey and Tupper, 1918; Bailey, 1936). Accompanying this development there has been a progressive decrease in the length of these elements (Bailey and Tupper, 1918; Bailey, 1920). 11. So far as the several categories of tracheids are concerned, the phylogenetic development in the Angiosperms has been from scalariform tracheids to circular bordered pitted tracheids (Jeffrey, 1917). 12. The diffuse arrangement of wood parenchyma cells is more primitive than are the various aggregate arrangements, such as banded apotracheal and

Habits of the Swamp Rice Rat, Oryzomys Palustris Palustris (Harlan)

Abstract: Along the South Atlantic coast line, illimitable marshes of swamp grass cover the mud flats of lowlands of the tidal zone (Fig. 1). Here, in the cover of dense vegetation, rice rats occur in great numbers, their runway threading the black mud covered daily by the tides, or rising into the higher ground which skirts the tidal zone. The abundance of these rodents, the ease of capture and their docile behavior in captivity, make them ideal laboratory animals. It is therefore surprising that so little has been recorded of their habits. Observations on rice rats were made by Audubon and Bachman (1854), to which little has been added to the present day. Goldman (918) has presented a brief review of the habits of these rodents. Harper (1927) gives some interesting data on the nests and behavior of this species in the Okefinokee Swamp of Georgia, while Svihla (1931) has recorded observations on the Texas rice rat (Oryzomys palustris texensis). Other than these accounts, published data on the life history of this widespread genus is all but lacking. Rice rats range from New Jersey and the central part of the Mississippi Valley southward, being well represented in nearly every part of South America and reaching their greatest development in the tropics. More than 150 species and subspecies have been described, but little other than a name has been assigned to the majority of these, the habits having been totally unexplored.

Observations on the Desert Gypsum Flora of Southwestern Texas and Adjacent New Mexico

Abstract: In his paper on gypsophilous plants of northern Mexico I. M. Johnston (1941) suggests the desirability of studying the plants of similar habitats in southwestern Texas and adjacent New Mexico. The following are preliminary notes concerning the gypsophiles of the latter area. They are based on collections and observations made by the author during August 1942, June and July, 1943, October 1944 and September 1945, principally in Hudspeth, Culberson and Reeves Counties, Texas, and Chaves and Eddy Counties, New Mexico as a part of a more extensive investigationt of the desert flora of this region.

A New Species of Heterosporium Pathogenic on Young Chinook Salmon

Abstract: Mycelium laminas fuscas hyphis subfuscis immersis atque hyalinis divaricatis compositas efformans; hyphae 1.5-4k diam.; cellulae plerumque 16-20k longae; conidiophora hyphis vegetativis similia; conidiosporae singulae alternato ordine vel irregulariter collocatae, sparse subtuberculatae, maturitate fuscae et plerumque triseptatae, elliptico-oblanceolatae in parte inferiore erostratae, saepe minute truncatae, apice hemisphaerico, quadriloculares, 1420longae, 4-6wt latae. Mycelium forming dark brown plaques of immersed pale-brown hyphae with hyaline hyphae erect from the surface and immersed in the medium at the margin of the growing colony; hyphae cylindrical, smooth walled, irregular in size (1.5) 2-4k in diameter, sometimes a bit irregularly swollen, branching at between 400 and 900 from the main axes; cells very variable in length but often 16 to 20,u, with the ends often somewhat swollen and constricted at the septa; conidiophores arising from the surface of the hyphal mass in culture as loose wefts of mycelium from which the spores usually arise as apedicellate lateral branches, or the spores may arise directly from surface mycelium not differing in appearance from the other hyaline or pale-brown hyphae; conidiospores sparsely low-tuberculate, becoming brown and almost always threeseptate at maturity, elliptic-oblanceolate in outline with no trace of a rostrum at the base though often minutely truncate there, locules regular in size and cylindrical or slightly swollen, particularly at the distal end, apex hemispherical, produced solitarily and laterally, alternately or irregularly on the conidiophores, quadrilocular, at maturity 14-20 x 4-6fL. The type, consisting of slides of cultured sporogenous mycelium and paraffin-sectioned material from infected fish organs, is deposited in the Dudley Herbarium of Stanford University (number 306407). Subcultures have been distributed to the Farlow Herbarium at Harvard University, to the University of California herbarium, to Dr. Gladys E. Baker of Vassar College,

A Change from Grassland to Forest Vegetation in the "Big Barrens" of Kentucky

Abstract: When the first white settlers came to Kentucky they found vast regions of grassland with only occasional trees, all of which had a stunted growth that made them unsuitable for building material, fences, and fuel. Most of the grassland was in the western half of the state and the main area, referred to as "Big Barrens," fomed a narrow strip extending from the Ohio River about thirty-five miles west of Louisville southward to the Tennessee State line and westward to the Cumberland River. The estimates concerning the extent of surface of this particular grassland ranged from 5,000 to 6,000 square miles.

Helminth Parasites of Birds and Mammals in Western Massachusetts

Abstract: Little is known of the helminths parasitic in wild birds and mammals of New England. Although a few isolated papers on single species occur in the literature, no reports of extended surveys for such parasites have been encountered. The importance of understanding the distribution of wild animal parasites has been indicated by many writers (Cameron, 1935; Van Cleave, 1937; etc.). Wild animals may act as reservoir hosts for domestic animal parasites. Some helminths may affect the distribution of animals seasonally and geographically. The health and vitality of wild animals may be seriously affected. Any data concerning the occurrence of such parasites are of importance in outlining conservation and control measures. It is hoped that the present survey may be of help to future investigators in indicating what helminth parasites are present in western Massachusetts, as well as to extend the known distribution of these worms.

Age, Growth, and Habits of the Hog Sucker, Hypentelium nigricans (LeSueur), in New York

Abstract: The hog sucker, Hypentelium nigricans (LeSueur), is a well known fish of the riffles and adjacent areas of warm, clear, shallow streams with rubble bottom. Its extensive range includes Minnesota and Lake of the Woods, the entire upper Mississippi River system, eastward to southern Ontario and New York; south to Georgia in the East, the Gulf slope of Mississippi, southwestern Arkansas, and eastern Oklahoma (Hubbs and Lagler, 1941: 42). Although it is sometimes caught by fishermen in the spring on hook and line, it is not oftern eaten because of its small average size and the presence of many small bones. It is also called hammerhead, hog molly, hog mullet, crawl-abottom, stone lugger, and stone toter. The bulk of its diet consists of insect larvae, crustaceans, diatoms and other minute forms of vegetation. When feeding it scrapes off the upper surface of rubble, turns over stones on the bottom, and sucks up the ooze, which includes a host of small organisms. Reighard (1920: 21) and Greeley (1935: 92) both report an interesting relationship between the feeding hog sucker and other fishes such as shiners, Notropis, and nothern smallmouth bass, Micropterus d. dolomieu. These fishes take a position downstream and feed on the aquatic insects and other forms dislodged as the hog sucker turns over rocks. As every boy who frequents small streams knows, hog suckers may easily be caught on worms or snared with a loop or hook as they lie quietly in shallow water. It is most commonly found in warm streams where it is generally associated with the northern smallmouth bass, in whose stomach it has been found. Large hog suckers are sometimes used as bait for muskellunge, northern pike and other large game fishes. It is occasionally found in lakes, usually near the mouths of streams, and apparently thrives in this habitat for the few that we have aged have grown much faster than stream specimens.

Variations in Abundance of Certain Invertebrates in William Trelease Woods, 1933-1938

Abstract: This paper differs from several others on the same area in that it proved possible to trace variations in abundance (annuation) for five consecutive years for several species and for four years for a larger number. Some effort was made to trace changes from season to season (aspection) and some results were worthy of record. The difficulties encountered made possible a statement of the best methods to follow. Several community studies have been made at the University of Illinois, largely in the two woodlands owned by the University and known as William Trelease Woods (formerly University Woods) and Brownfield Woods. McDougall (1922) has given an account of the plants in William Trelease Woods, and in 1928 he and Penfound made a further report upon the plant forms there. Weese (1924) studied the invertebrates in this woodland during 1921-1922. Several later workers have considered various phases of the community problem. Blake (1926) gave an account of hibernation among invertebrates, based on his observations made during the winter of 19241925. In a later paper (1931) he considered the spring population of 1925. Rutherford (1929), working in Brownfield Woods, studied the movements of insects in hibernation. Smith-Davidson (1930) reported upon the treelayer society in both Brownfield and William Trelease Woods, a phase heretofore neglected. Her later paper (1932) gave an excellent account of seasonal variability and its effect upon total populations as seen in 1925-1926. In 1933 studies of the animal community at William Trelease Woods were begun in the desire to have continuous records of animal populations over a period long enough to indicate the reactions of the animals to weather changes. Collections of invertebrates from 1933 to 1935 were made by Rice (1944) and were continued from 1935 to 1936 by Kanatzar, who prepared a master's thesis which was not published. The writer's work began in the fall of 1936 and continued until Septembet, 1938. Rice (1946) tested the methods used and analyzed the populations of forest species with reference to weather and bird predation. Her work began October 1, 1934, and ended with September, 1935. However, she made use of Kanatzar's data through November, 1935, and began her most serious analysis with November 1, 1933, and ended with October 31, 1935. It was possible for the writer to report on nine species through the entire period, on six species through Kanatzar's period of study, and two species through Rice's period of study with Kanatzar's year omitted. Only one species analyzed by Rice was graphed by the author and this for a different purpose.