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Showing papers in "The Biological Bulletin in 1968"


Journal ArticleDOI
TL;DR: Abnormal development is correlated with a telescoping of the early events in adult differentiation, followed by the precocious deposition of new cuticle, and Sensitivity to excessive ecdysone or to juven...
Abstract: 1. Six ecdysones of plant origin are compared with synthetic α-ecdysone in terms of their ability to provoke normal or abnormal development of diapausing pupae and isolated pupal abdomens of the cynthia silkworm (Samia cynthia).2. The activity of the seven materials ranks in the following order: cyasterone > ponasterone B > ponasterone A > ponasterone C > α-ecdysone > β-ecdysone > inokosterone.3. All seven materials provoked normal adult development when injected in critical doses ranging from 0.2 µg. (cyasterone) to 10 µg. (inokosterone).4. All materials except µ-ecdysone caused extremely abnormal development when excessive doses were administered to pupae or isolated pupal abdomens. The typical result was the formation of naked or nearly naked non-viable moths which failed to complete adult development.5. Abnormal development is correlated with a telescoping of the early events in adult differentiation, followed by the precocious deposition of new cuticle.6. Sensitivity to excessive ecdysone or to juven...

185 citations


Journal ArticleDOI
TL;DR: The photosynthetic pigments of the brown symbiotic algae (zooxanthellae) isolated from five tridacnid clams and nine corals were found to be identical with the pigment of the dinoflagellate Amphidinium.
Abstract: 1. The photosynthetic pigments of the brown symbiotic algae (zooxanthellae) isolated from five tridacnid clams and nine corals were found to be identical with the pigments of the dinoflagellate Amphidinium. Identifications were carried out by two-dimensional paper chromatography and by absorption spectrophotometry. Both zooxanthellae and dinoflagellates contained cholorphylls a and c, β-carotene, peridinin, neo-peridinin, dinoxanthin, neo-dinoxanthin, diadinoxanthin, and three minor xanthophyll fractions not previously described.2. Peridinin, crystallized from Tridacna gigas, or isolated by paper chromatography from Tridacna crocea, Pocillopora or the dinoflagellate Amphidinium, showed similar absorption characteristics in different solvents. The extinction coefficient of crystalline peridinin in acetone was E1 cm1% 1340.3. Clam zooxanthellae (and the dinoflagellates Amphidinium and Gymnodinium) contained a much higher proportion of chlorophyll c than coral zooxanthellae.4. No chlorophyll decomposition pr...

178 citations


Journal ArticleDOI
TL;DR: The role of the blood is to serve, not as a reservoir, but as a pipeline through which ecdysone flows from the ring-gland to its sites of action and swift inactivation, which can account for its low titer in both the blood and tissues.
Abstract: 1. Ecdysone is in a highly dynamic state after its injection or its secretion by the ring-gland of Sarcophaga peregrina. Hormonal activity is rapidly destroyed by an inactivating mechanism which is present in the tissues but not in the blood.2. Inactivation is blocked by low temperatures or anaerobic conditions—a finding that implicates chemical and, more particularly, oxidative reactions. The mechanism in question could be demonstrated in larval fragments but not in crude or fractionated homogenates.3. When injected into mature larvae, 1 µg of α-ecdysone loses 50% of its activity in 1 hour and 98% in 8 hours. Lower doses show even briefer "half-lives."4. The rapid inactivation of ecdysone can account for its low titer in both the blood and tissues. Thus at the "critical period" for puparium formation, the entire larva contains only 2.5 nanograms, corresponding to only 7% of a Sarcophaga unit.5. The evidence points to the accumulation, not of the hormone itself, but the covert biochemical and biophysical ...

162 citations


Journal ArticleDOI
TL;DR: A green alga Ostreobium (Siphonales) can live and photosynthesize within the massive coral and shows saturation at or below 1000 erg, and a high activity band was noticeable around 540 nm, which was also visible in the in vivo excitation spectrum of fluorescence.
Abstract: 1. The living part of the massive coral Favia is inhabited by a symbiotic dinoflagellate (Zooxanthellae) which resembles Symbiodinium microadriaticum. Intensity/response curves for this alga show that saturation occurred at 95,000 erg. cm.-2 sec-1 in blue light (440 nm). Action spectrum determinations were performed either with an automatic field instrument, or by a point method. The results are mainly as to be expected for a dinoflagellate. A high activity band was noticeable around 540 nm. A similar band was also visible in the in vivo excitation spectrum of fluorescence, as well as in the in vivo absorption spectrum (Shibata, unpublished data).2. A green alga Ostreobium (Siphonales) can live and photosynthesize within the massive coral. The light levels within the coral are very low; however, wave-lengths above 700 nm are preferentially transmitted by the living part of the coral with the zooxanthellae. Ostreobium showed saturation at or below 1000 erg. cm.-2 sec1 at 440 nm. Some samples showed photoox...

151 citations


Journal ArticleDOI
TL;DR: Observations of lowered rates of respiration in air are explained by lowered oxygen tensions in mantle cavity fluid in air-gaping mussels.
Abstract: 1. Normally, the intertidal mussel, Modiolus demissus, does not close its valves when exposed to air by low tides: it air-gapes. Desiccation resulting from water loss is a physical phenomenon and a surface-to-volume relationship causes small mussels to reach the median lethal weight loss of 36-38% more rapidly than large mussels.2. Evaporative cooling is demonstrable, but no significant difference in high tempertaure survival was observed between gaped and non-gaped mussels. The LD50 for a 10-hour heat stress lies between 36.4 and 37.8° C. and large mussels are more labile than small ones to thermal stress.3. Median survival times of mussels in gaseous environments are proportional to the volume of oxygen present. Observations of lowered rates of respiration in air are explained by lowered oxygen tensions in mantle cavity fluid in air-gaping mussels.4. Mussels living in moist marsh mud occupy a higher intertidal position than those living on bridge pilings which are more exposed to the aerial environment....

94 citations


Journal ArticleDOI
TL;DR: The initiation of sexual reproduction and duration of diapause in the resulting embryo was studied in a population of Daphnia pulex Leydig that restricts such to the autumn, and exposure to short days after birth may permit a large percentage of parthenogenic broods in which the necessary males are produced, thereby providing males in advance ofSexual reproduction in the population.
Abstract: 1. The initiation of sexual reproduction and duration of diapause in the resulting embryo was studied in a population of Daphnia pulex Leydig that restricts such to the autumn. Initiation is under the control of a density associated stimulus that is permitted to function only in short-day photoperiods. In short days the proportion of sexual broods is linearly related to the log of culture density.2. Critical photoperiod (50% sexual broods) at 19° C. was L:D 12 3/4:11 1/4, and only 15 minutes longer at 12° C. The prenatal life of the mother is the more sensitive to photoperiodic induction of sexual reproduction. Exposure to short days after birth may permit a large percentage of parthenogenic broods in which the necessary males are produced, thereby providing males in advance of sexual reproduction in the population. In long days the mothers quickly revert to parthenogenesis, and the extent of reversal is apparently related to age of the grandparent when the mother was born.3. Sexually derived embryos from...

88 citations


Journal ArticleDOI
TL;DR: The results substantiate an earlier suggestion that low phosphate did not limit the rate of phytoplankton growth in the northeastern tropical Pacific Ocean and verify previous use of a linear nutrient relationship in productivity equations given by other authors.
Abstract: Cell division in batch cultures of the tropical oceanic diatom, Chaetoceros gracilis, was measured in artificial medium containing different initial amounts of phosphate. The rate of growth was limited by phosphate concentrations below approximately 0.22 µg.at./l. and appeared to be a linear function of concentration rather than a hyperbolic function. Ks in the hyperbolic relationship equating growth rate and concentration would be about 0.12 µg.-at./l. The results substantiate an earlier suggestion that low phosphate did not limit the rate of phytoplankton growth in the northeastern tropical Pacific Ocean; and they also verify previous use of a linear nutrient relationship in productivity equations given by other authors. Pauses in cell division at low phosphate concentrations are either attributed to the induction of phosphatases which can act on stored intracellular phosphorus or to low extracellular concentrations. Final cell numbers were a linear function of initial phosphate concentration up to abou...

77 citations


Journal ArticleDOI
TL;DR: A biannual reproductive cycle was observed in Spisula solidissima gonads during 3 of the 4 years in which samples were taken from offshore New Jersey, and temperature clearly delays or hastens the gametogenic cycle and stimulates spawning of ripe surf clams in the laboratory.
Abstract: 1. A biannual reproductive cycle was observed in Spisula solidissima gonads during 3 of the 4 years in which samples were taken from offshore New Jersey. 2. The biannual cycle was characterized by a major mid-year spawning and minor late-year spawning. A second annual reproductive cycle may be neither typical for surf clams throughout their geographical range nor always an annual event in clams from New Jersey. 3. A delayed spawning and single annual cycle in 1965 was related to colder environmental temperatures than were observed in the three earlier years of the study. 4. Abrupt temperature changes were not clearly a cause of spawning in the natural populations of surf clams. Partially spawned clams were found in the samples in advance of abrupt temperature changes. Temperature, however, clearly delays or hastens the gametogenic cycle and stimulates spawning of ripe surf clams in the laboratory.

66 citations


Journal ArticleDOI
TL;DR: The deposition, structure, and composition of the jelly surrounding the egg of Xenopus laevis were studied cytochemically and biochemically, and it is suggested that J1 contains sulfate.
Abstract: 1. The deposition, structure, and composition of the jelly surrounding the egg of Xenopus laevis were studied cytochemically and biochemically. During its passage through the oviduct, the egg is invested with three layers of jelly designated J1, J2, and J3, from innermost to outermost. Particular emphasis was placed on analyzing the layers separately.2. All layers gave positive histochemical tests for neutral polysaccharides. J2 and J3 stained the most intensely. The sugars present in the polysaccharides of each layer were identified chromatographically. J1, J2, and J3 all contain fucose, glucosamine, and galactosamine. Galactose is present in J1 and J2 and possibly in J3. J3 may also contain mannose or mannosamine.3. On the basis of the histochemical tests it is suggested that J1 contains sulfate. The weak positive reactions for acid polysaccharides in J2 and J3 indicate the presence of carboxyl groups only. Since no uronic acid was found in the jelly it is proposed that the carboxyl groups are part of a...

65 citations


Journal ArticleDOI
TL;DR: This is the first report of dilute urine in any decapod other than crayfishes, and blood and urine are isosmotic throughout the tested range of salinities.
Abstract: 1. Syncaris pacifica (Atyidae) is restricted to fresh water, like most members of the family. The striking osmotic adaptation in this shrimp is elaboration of urine markedly hypo-osmotic to blood. In fresh water, the following average body fluid concentrations were found: blood,Δi 0.73° C. (F. P. depression), chloride, 185 meq./L.; urine, Δi 0.18° C. This is the first report of dilute urine in any decapod other than crayfishes.2. Palaemon macrodactylus (Palaemonidae) is a strong regulator over the range 2-150% SW, and inhabits a wide range of salinities in the San Francisco Bay estuarine system. Blood and urine are isosmotic throughout the tested range of salinities. Hyper-regulation occurs below 60% SW, and hypo-regulation in higher salinities. Between 20% and 100% SW, Δi increases only from 1.19° to 1.65° C., as environmental salt concentration increases from Δ0 0.50° to 2.08° C.

64 citations


Journal ArticleDOI
TL;DR: The persistence of the pattern of nocturnal activity for several days under conditions of constant low light intensity confirmed that emergence and subsequent activity were under rhythmic control.
Abstract: 1. A close relationship exists between the day-night cycle and the times of activity of pink shrimp. The shrimp bury beneath the substrate during the day but emerge at the time of sunset and are active at night.2. Emergence from the substrate is markedly synchronized in all members of the population. This study elucidates the mechanisms whereby this synchrony is maintained.3. The persistence of the pattern of nocturnal activity for several days under conditions of constant low light intensity confirmed that emergence and subsequent activity were under rhythmic control.4. Resynchronization of the phase of the rhythm controlling emergence to a shift in the light-dark cycle indicated that the light-dark cycle itself, or some component of it, is responsible for maintaining the relationship between emergence and the day-night regime.5. The close association between emergence and the time of light-dark transition indicated the possibility that the latter was the important component of the Zeitgeber responsible ...

Journal ArticleDOI
TL;DR: The results indicate that Corella is a primary colonizer, preferring to settle on clean surfaces, and growth is rapid during the summer, but individuals grow at a slower rate and live longer during the winter; the life span then is seven or eight months.
Abstract: 1. A one-year field study of the ecology of the solitary ascidian Corella willmeriana Herdman was conducted between April, 1966, and April, 1967, at the Bremerton Yacht Club, Bremerton, Washington, where two polyvinyl chloride frames containing glass plates were examined at monthly intervals. 2. The results indicate that Corella is a primary colonizer, preferring to settle on clean surfaces. Growth is rapid during the summer, when sexual maturity, corresponding to a size of 12 mm., may be attained in three months and life span is approximately five months. Individuals grow at a slower rate and live longer during the winter; the life span then is seven or eight months. 3. Very young specimens of Corella are frequently overgrown during the winter by the colonial ascidian Diplosoma macdonaldi. The causes of death of adult Corella are not completely known, although a small percentage of them are eaten by the polyclad flatworm Eurylepta leoparda. A luxuriant spring growth of filamentous diatoms may cause death of adult Corella by smothering them.

Journal ArticleDOI
TL;DR: Three stages in the formation of the new setae can be used to subdivide intermolt stage D1 into three substages and the rate of reabsorption of the membranous layer is not correlated with the rates of seta formation.
Abstract: 1. New setae can be seen in the process of development in the uropods and telson of living specimens of Orconectes sanborni. The setae form by secretion of a tube within a tube. Three stages in the formation of the new setae can be used to subdivide intermolt stage D1 into three substages.2. The beginning of seta formation defines the beginning of stage D1. Before beginning this stage, the membranous layer of the cuticle begins to be reabsorbed the epidermis separates from the old cuticle, gastroliths begin to be formed, and the rate of regenerating limb growth increases sharply except in individuals which do not display such increase at all.3. The membranous layer had been completely reabsorbed in about half the specimens examined in each D1 substage. Therefore, the rate of reabsorption of the membranous layer is not correlated with the rate of seta formation.4. Ratios of gastrolith length to carapace length and of regenerating limb bud length to carapace length varied in different specimens, but the var...

Journal ArticleDOI
TL;DR: The results of experimental infections in Rutilus rutilus and Xenopus laevis are similar to those which follow testosterone implantation, and it is suggested that the parasite produces an anti-gonadotrophic substance.
Abstract: 1. Infections with the plerocercoid larvae of a pseudophyllidean cestode, Ligula intestinalis, are shown to be associated with histological changes in the pituitary gland and gonads of its host.2. The results of experimental infections in Rutilus rutilus and Xenopus laevis are similar to those which follow testosterone implantation. It is suggested that the parasite produces an anti-gonadotrophic substance.

Journal ArticleDOI
TL;DR: Migrating spotted salamanders entered and departed from breeding ponds at or near the same point for three consecutive years and failed to orient to their pond or in the direction they were moving when originally collected.
Abstract: 1. Migrating spotted salamanders entered and departed from breeding ponds at or near the same point. This pattern was repeated for three consecutive years.2. Animals migrating in a meadow to and from the breeding pond often traveled in a corridor 10 to 30 m. wide. Several variations from this plan were noted.3. Spotted salamanders displaced up to 500 m. may return to the home breeding pond.4. Migrating adults transferred from the border of one breeding pond to within 10 m. of another breeding pond did not move to the new pond as did controls.5. Migrating adults transported from the border of one pond to the center of another failed to orient to the old pond or in the direction they were moving when captured.6. Some adults adopted a new breeding pond when displaced.7. Animals moved to a laboratory and then released outdoors in an unfamiliar area failed to orient to their pond or in the direction they were moving when originally collected. Handling and laboratory conditions may have altered normal behavior....

Journal ArticleDOI
TL;DR: The pigment composition of Ostreobium closely resembled that of two members of the Siphonales, Halimeda and Codium, therefore, this alga may be appropriately grouped within the Sphonales.
Abstract: 1. The photosynthetic pigments of the green subsurface layer (Ostreobium) of The pigments found were chlorophylls a and b, α- and β-carotene, siphonein, traces the brain coral Favia were studied by two-dimensional paper chromatography. of siphonaxanthin and neoxanthin, and an unknown yellow-orange xanthophyll.2. The pigment composition of Ostreobium closely resembled that of two members of the Siphonales, Halimeda and Codium. Therefore, this alga may be appropriately grouped within the Siphonales.3. The three algae, Halimeda, Codium, and Ostreobium contained a high proportion of chlorophyll b, from two-thirds to three-quarters that of chlorophyll a.

Journal ArticleDOI
TL;DR: Urchins manifested partial seasonal acclimation of oxygen uptake as indicated by the fact that winter oxygen consumption curves were well above summer curves at the corresponding temperatures and mean summer oxygen uptake was higher at the summer ambient than the mean winter oxygen uptake at the winter ambient.
Abstract: 1. In the laboratory Eucidaris tribuloides showed a food preference for rock infested with the boring sponge Cliona lampa over turtle grass (Thalassia testudinum), several algae, and fish strips. 2. In the laboratory, urchins consumed wet rock infested with Cliona lampa at rates ranging from less than one to over three gm. per day depending on the size of the urchin. 3. Oxygen consumption of urchins was measured in the laboratory with a modified Scholander volumetric respirometer. 4. Oxygen uptake decreased significantly during the first day of starvation, but then remained relatively stable during several successive days of starvation. 5. There was not a significant correlation between gonad index or sex of the urchin and relative oxygen uptake. 6. Relative oxygen consumption decreased with increasing size of the urchin. Values for "b" indicated an oxygen uptake which was almost proportional to surface area at 20° and 30 ° C. 7. Oxygen uptake fluctuated during the first hour when urchins were placed in water several degrees colder than their ambient water. At the end of this hour, however, the rate of oxygen uptake had become relatively stable. Well-fed urchins manifested greater changes in their stabilized rates of oxygen uptake (Q10) at different temperatures than did starved urchins. 8. Urchins manifested partial seasonal acclimation of oxygen uptake as indicated by the fact that winter oxygen consumption curves were well above summer curves at the corresponding temperatures. The acclimation was probably not complete since mean summer oxygen uptake was higher at the summer ambient than the mean winter oxygen uptake at the winter ambient.

Journal ArticleDOI
TL;DR: The results show that, when measured at 20-23°, the 10° acclimated fish possess liver protein synthetic capacity about 75% greater than fish maintained at the higher temperature.
Abstract: Liver protein synthesis was measured with a rapid arterial injection procedure in control (20-23°) and cold-acclimated (10°) toadfish. The results were expressed as the cpm of radioactive amino acids incorporated into protein compared to cpm of free radioactivity in the liver homogenate, to correct for variability in injections and in uptake of amino acids by the liver. The results show that, when measured at 20-23°, the 10° acclimated fish possess liver protein synthetic capacity about 75% greater than fish maintained at the higher temperature. Two series of experiments, in which fish were maintained in running sea water aquaria or in static artificial sea water aquaria, gave comparable results. The livers were analyzed for DNA, RNA, protein and free amino acids. The levels of these constituents resembled those in mammalian liver with the exception of RNA, which was lower. Under the conditions of these experiments no significant changes were observed in the constituents measured as a result of two-week c...

Journal ArticleDOI
TL;DR: Individual variation in coelomic fluid AAN normally occurs intraspecifically and possible sources of variability are considered, and levels of Amino-acid concentration always increases posteriorly, and pH usually decreases in the same direction.
Abstract: 1. Coelomic fluid amino-acid nitrogen (AAN) shows great variability among the fourteen polychaete species examined, ranging from about 1 to 5 mg./l00 ml. in subtidal species to more than 150 mg./l00 ml. (about 100 mM/1.) in an intertidal species. The concentration of ammonia nitrogen (NH3 N) in coelomic fluid is roughly about 5% of the AAN.2. Individual variation in coelomic fluid AAN normally occurs intraspecifically and possible sources of variability are considered.3. Axial gradients exist in all species examined for this. Amino-acid concentration always increases posteriorly, and pH usually decreases in the same direction.4. Intracellular (body-wall) AAN is relatively less variable both within and between species, the range being from about 130 mM/kg. tissue water in Aphrodite to about 400 mM/kg. in two terebellids. Concentrations do not appear to correlate with habitat. Tissue NH3 N levels are slightly higher proportionately than in coelomic fluid, and are more variable.

Journal ArticleDOI
TL;DR: Two distinct reproductive behavior patterns are associated with the release of zoea on the 25th day of development, i.e., mating and obstetrical behavior in the spider crab, Libinia emarginata, and their possible initiation by pheromone(s).
Abstract: 1. Data concerning reproductive behavior and development in the spider crab, Libinia emarginata (L.) are recorded. Ovigerous females were collected from early June to early September. Females are apparently able to produce at least 3-4 consecutive broods of 25 days development each during a breeding season. 2. Two distinct reproductive behavior patterns are associated with the release of zoea on the 25th day of development, i.e., mating and obstetrical behavior. These male-female associations are stereotyped behaviors. The position of the bodies of the male and female differ in the two behavior patterns. 3. The predictability of onset of these behaviors and the specificity of the patterns suggest their possible initiation by pheromone(s).

Journal ArticleDOI
TL;DR: In several species osmotic dilution causes a rise in coelomic fluid amino-acid levels, suggesting direct transfer of amino acids from tissues to body fluid, and in one species, Thelepus crispus, there is a 50 to 75% fall, although this is not true in two closely related species.
Abstract: 1. Ten species of polychaetes were exposed to 75% and 50% sea water for 1 to 4 days, and measurements of amino-acid levels in the coelomic fluid and body wall were made. Individuals of all species, both intertidal and subtidal, survived the experimental period at both dilutions.2. Osmotic stress at lowered salinities results in a decrease in intracellular amino-acid levels. This is primarily due to tissue hydration, although in some species, especially Nephtys ciliata and Abarenicola pacifica, hydration is minimal or absent and "active" movement of amino acids contributes a larger share of the decrease.3. In several species osmotic dilution causes a rise in coelomic fluid amino-acid levels, suggesting direct transfer of amino acids from tissues to body fluid. In one species, Thelepus crispus, there is a 50 to 75% fall in coelomic fluid amino-acid level, although this is not true in two closely related species. The data indicate that polychaetes may use a variety of mechanisms to regulate their amino-acid ...

Journal ArticleDOI
TL;DR: The posterior third of the primitive streak was implanted into the 2 ½-day chick embryo and untreated implants were similar to those of the serum albumin series, but treatment with liver RNA resulted in a significant increase in the rate of growth and differentiation.
Abstract: The posterior third of the primitive streak was implanted into the 2 ½-day chick embryo. Both growth and differentiation of the untreated implants were similar to those of the serum albumin series. Treatment with liver RNA, however, resulted in a significant increase in the rate of growth and differentiation. When liver RNA was incubated with RNase, the products furthered the growth and feather bud formation, but reduced the differentiation of the endodermal derivatives, especially gut.

Journal ArticleDOI
TL;DR: Pleopod ventilative responses in low-oxygen sea water were investigated in two species of Callianassa, with animals relatively unrestrained during experiments, in tubes simulating actual burrow conditions.
Abstract: 1. Pleopod ventilative responses in low-oxygen sea water were investigated in two species of Callianassa, with animals relatively unrestrained during experiments, in tubes simulating actual burrow conditions.2. In C. affinis hyperventilation stroke frequencies up to 120/min. were recorded in low pO2, with maximum ventilation oftentimes occurring upon readmission and detection of oxygen-containing sea water.3. In low-oxygen sea water C. californiensis was clearly able to discriminate between samples of aerated and low-oxygen sea water, as indicated by significantly greater ventilation beginning within a few seconds after detecting the oxygen-containing sea water.

Journal ArticleDOI
TL;DR: Acetate uptake is inhibited by other short chain fatty acids but is unaffected by a variety of other compounds, and inhibitions were found to be partially competitive in the case of propionate, butyrate, valerate and octanoate and fully competitive inthe case of formate.
Abstract: 1. At low substrate concentrations (below approximately 2 mM) Hymenolepis diminuta absorbs acetate by a mediated process; at high substrate concentrations the main mode of entry is diffusion.2. Hydrogen ion concentration affects acetate uptake. At low pH the rate is increased and there is a larger diffusion component. Inhibition of acetate uptake by propionate is depressed at low pH.3. Acetate uptake is inhibited by other short chain fatty acids but is unaffected by a variety of other compounds. The kinetics of the inhibitions were examined and inhibitions were found to be partially competitive in the case of propionate, butyrate, valerate and octanoate and fully competitive in the case of formate. Butyrate uptake is also inhibited by these compounds.4. The data are discussed in terms of transport of fatty acids, lipid metabolism in cestodes and possible significance in the ecology of the organism.

Journal ArticleDOI
TL;DR: Fat body excision in females of both species (sexually mature animals) resulted in the atresia of all deutoplasmically active follicles and treatment involving the administration of estrogen in both species subsequent to ovariectomy inhibited any increase in fat body weight.
Abstract: 1. Percentages of the total body weight comprised by both fat bodies ranged in field samples of female Ameiva quadrilineata from 0.10 to 2.55 and in female A. festiva from 0.10 to 2.39. Percentages from field sample males ranged lower, from 0.07 to 0.89 in A. quadrilineata and from 0.05 to 1.09 in A. festiva.2. Ovariectomy in both species was followed by an increase in fat body weight compared with field controls and with sham-operated animals. Treatment involving the administration of estrogen in both species subsequent to ovariectomy inhibited any such increase in fat body weight.3. Orchidectomy in both species was followed by an increase in fat body weight. Specimens of Ameiva quadrilineata which were castrated and also treated with testosterone showed no such increase.4. Fat body excision in females of both species (sexually mature animals) resulted in the atresia of all deutoplasmically active follicles.5. An adaptive significance of fat bodies in A. festiva and A. quadrilineata is suggested in terms...

Journal ArticleDOI
TL;DR: The bisexual strain from the Great Salt Lake was obtained bacteria-free by serial washes of the wintering eggs in Merthiolate and the parthenogenetic strains from the Comacchio salines was axenized by serialWashes of gravid females and nauplii in antibiotics; the yeast infection was eliminated by high salinity.
Abstract: 1. Two tetraploid strains of Artemia salina were axenized. The bisexual strain from the Great Salt Lake was obtained bacteria-free by serial washes of the wintering eggs in Merthiolate. The parthenogenetic strain from the Comacchio salines was axenized by serial washes of gravid females and nauplii in antibiotics; the yeast infection was eliminated by high salinity.2. Methods for the maintenance of the bacteria-free stocks were defined. Various phytoflagellates were found suitable food organisms for both strains of Artemia when grown in appropriately enriched sea water.3. Two species of Dunaliella were adapted to grow in synthetic salt solutions ranging from 0.5 to 20.5% total salts. These conditions permitted the study of the effect of salinity on egg production of Artemia in diaxenic culture.4. Great Salt Lake Artemia grown at various salinities, in inorganic enrichments and fed ad libitum with salinity-adapted D. viridis and D. salina, failed to deposit eggs in solutions containing less than 3% salts. ...

Journal ArticleDOI
TL;DR: Observations were made on the morphology, especially that of the circulatory system, the feeding, and the behavior of the polychaetous annelid Magelona sp.
Abstract: 1. Observations were made on the morphology, especially that of the circulatory system, the feeding, and the behavior of the polychaetous annelid Magelona sp. from the vicinity of Woods Hole, Massachusetts.2. Features of particular interest related to the circulatory system include an anterior dorsal vessel which is divided into a series of chambers set apart by valves. The chambers undergo a precisely timed filling and emptying and pass blood forward to a heavily muscularized portion of the dorsal vessel whose contractions provide the primary pressure for movement of the blood. Segmentally arranged valves were noted in the posterior part of the dorsal vessel.3. Burrowing is accomplished by the insertion of the prostomium into the substratum and the subsequent extrusion of the proboscis. This extrusion is brought about primarily by the hydraulic pressure of blood which has been expelled from the anterior region of the body by the contraction of all anterior somatic muscles except the proboscidial retracto...

Journal ArticleDOI
TL;DR: Comparison of the larvae ofPolyonyx gibbesi with those of Polyonyx quadriungulatus, an eastern Pacific species, shows the zoeae and megalopae to be almost identical both in appendages and in form, numbers, and placement of setae.
Abstract: 1. The larval development of the porcellanid crab, Polyonyx gibbesi, a commensal with the polychaete worm Chaetopterus variopedatus, is described and illustrated. Two series of larvae were hatched and maintained in the laboratory, one fed with Artemia nauplii and the other starved. Members of each series were held at 10°, 15°, 20°, 25° and 30° C. At 25° C. the fed larvae hatched as prezoeae and molted through two additional zoeal stages to the megalopa. Duration of the pre-zoeal stage is about two hours, each of the zoeal stages usually lasts six to seven days and the megalopa lasts 12-14 days before molting to first crab. No crab stages were obtained above or below 25° C. and no megalopae were obtained below 20° C. Starved larvae died before attaining Stage II.2. Comparison of the larvae of Polyonyx gibbesi with those of Polyonyx quadriungulatus, an eastern Pacific species, shows the zoeae and megalopae to be almost identical both in appendages and in form, numbers, and placement of setae. Similarity of ...

Journal ArticleDOI
TL;DR: Spio setosa exhibits poecilogony, spawning once in the spring, resulting in benthic larvae; again in the fall, with pelagic larvae, and in response to lack of substratum, most Spio larvae metamorphosed, forming tubes of mucus.
Abstract: 1.Spio setosa exhibits poecilogony, spawning once in the spring, resulting in benthic larvae; again in the fall, with pelagic larvae.2. Pelagic larvae from 4- to 22-setigers were collected between mid-October and mid-February in Great Harbor, Woods Hole, Massachusetts. Larvae were reared in laboratory culture through metamorphosis and juvenile stages.3. The morphology of pelagic larvae paralleled generally that of benthic larvae with the following exceptions: pelagic larvae from 6- to 13-setigers were smaller than comparable benthic larvae; pelagic larvae had gastrotrochs on segments 3, 5, 7, 9, 12, 14, rarely on 15; a rigid pattern of black pigment spots was present on pelagic larvae; pelagic larvae were planktotrophic; metamorphosis occurred at 18- to 20-setigers.4. In response to lack of substratum, most Spio larvae metamorphosed, forming tubes of mucus. Some larvae did not metamorphose for periods up to two months, either increasing in size and number of segments, or just increasing in size.5. Larvae ...

Journal ArticleDOI
TL;DR: Study of the structure and mode of life of Malleus regula provides the basis for consideration of the "hammer" species, M. malleus and M. albus, and the typically rounded Isognomon ephippium leads to that of the elongated I. isognomon.
Abstract: 1. Study of the structure and mode of life of Malleus regula provides the basis for consideration of the "hammer" species, M. malleus and M. albus. 2. M. regula occurs byssally attached, vertically disposed on rocky substrates associated with mud and is widely distributed in the tropical Indo-Pacific. 3. The distal two-thirds of the elongated shell is exclusively prismatic. By means of special pallial retractors the mantle lobes can be withdrawn within the nacreous region. 4. The massive opisthodetic ligament has a short secondary extension of fusion layer. 5. A promyal chamber on the right side proximal to the adductor increases water flow into the exhalant chamber. 6. The long filibranch ctenidia provide a vertically extended food-collecting surface. 7. The foot is concerned with planting of the massive byssus which emerges through a notch in the right valve but on the under ( i.e., dorsal) surface. There is also a unique and very long accessory foot, ventrally grooved, everywhere ciliated and in constant writhing activity due to blood pressure and intrinsic muscle. Moving freely throughout the lower mantle cavity it can only be concerned with cleansing. 8. Pseudofaeces are ejected from the distal tip of the mantle cavity. 9. M. malleus, the black hammer shell, occurs vertically embedded in coarse sand or sandy gravel. Byssus threads are attached to fragments within the substrate. The great anterior and posterior elongations of the hinge line (also exclusively prismatic) are separated by the byssal notch (now affecting both valves). 10. Shells are usually excessively irregular due to the great exposure to damage and the almost unlimited powers of rapid repair by the three pallial extensions. 11. M. albus, the white hammer shell, is stouter and inhabits muddy sand. During growth it loses the byssus with reduction of the foot and byssal retractors and closure of the byssal notch. The accessory foot is not affected. The animal becomes anchored in the substrate exclusively by the anterior and posterior extensions of the shell. 12. Description of the typically rounded Isognomon ephippium leads to that of the elongated I. isognomon which occupies precisely the same habitat as M. regula. 13. It lacks the pallial retractors, promyal chamber and accessory foot of Malleus, the nacreous region is more extended distally and the ligament is multivincular (the formation of which is discussed), producing some posterior, but never any anterior, extension of the hinge line. 14. A remarkably dense mixed bed of M. regula and I. isognomon in Darvel Bay, Sabah (Borneo), is described. Different spawning periods, by preventing competition during settlement, may account for this complete intermixing of sympatric species, which, however, are generalized herbivores where numbers are not limited by food supply. 15. From a basic epifaunal habit (Pteria, Isognomon, M. regula), members of the Pteriacea have become adapted for infaunal life within sponges (Vulsella, Crenatula) or within soft substrates ( M. malleus, M. alba and the Pinnidae). 16. There is final discussion about elongation in monomyarians, i.e., in the genus Malleus and in I. isognomon.