Brewers Condensed Solubles (BCS), a by-product of the brewing industry, was evaluated as a nutrient source for rearing juvenile oysters (Crassostrea virginica) and clams (Mercenaria mercenaria). The BCS was used to culture bacteria which were fed to colorless flagellates which were in turn fed to the oysters and clams. The overall growth efficiency of oysters on BCS was 473 mg of oyster (whole weight) per g of BCS (dry weight). Fourteen isolates representing nine genera of bacteria were isolated from BCS enrichment cultures. Specific growth rates of the isolates at &24\sp\circ{lcub}\rm C{rcub}& on a BCS medium ranged from 0.48 &{lcub}\rm h\sp{lcub}-1{rcub}{rcub}& to 0.11 &{lcub}\rm h\sp{lcub}-1{rcub}{rcub}.& The conversion of BCS to bacterial biomass was examined for four isolates with supplements of 0, 38, 76, and 152 mg/l of ammonium sulfate. The largest bacterial biomass (127 mg/g BCS) was obtained with Pseudomonas marina. The largest bacterial biomass when averaged over all bacterial isolates was obtained with 38 mg/l of ammonium sulfate. Yields of P. marina on BCS ranged from 27.4% for no ammonium sulfate addition to 38.5% with 38 mg/l of ammonium sulfate. The effects of dissolved nutrients, salinity, temperature, shaking, bacterial concentration, and bacterial species on the growth rates of five species of colorless flagellates were examined. None of the colorless flagellates could be raised on the dissolved nutrients in BCS, all required a bacterial diet. Shaking, salinity, and the bacterial isolate used as food had little effect on the flagellate growth rates. Temperature and bacterial concentration had pronounced effects. The greatest growth rates were recorded at temperatures between 21 and &26\sp\circ{lcub}\rm C{rcub}.& Growth rates increased with increasing bacterial concentration in a manner suggestive of Michaelis-Menten kinetics. Maximum specific growth rates ranged from 0.11 &{lcub}\rm h\sp{lcub}-1{rcub}{rcub}& to 0.16 &{lcub}\rm h\sp{lcub}-1{rcub}{rcub}.& Yields of colorless flagellates growing on bacteria ranged from 0.30 to 0.42. The growth of oysters and clams fed colorless flagellates. BCS enrichment cultures, and bacteria was compared to the growth of starved controls and animals fed Tetraselmis suecica. Paraphysomonas vestita was the only species of colorless flagellate to consistently result in growth greater than the starved control. The BCS enrichment culture varied greatly in its nutritional value. The average oyster growth on P. vestita was 55% of the growth obtained with T. suecica. Oysters fed combinations of T. suecica and P. vestita did not grow as rapidly as on a pure diet of T. suecica. No growth occurred when oysters and clams were fed a purely bacterial diet.

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The convergent gliding adaptations in four mammalian families (Sciuridae, Anomaluridae, Cynocephalidae, and Phalangeridae) are compared. These adaptations are contrasted with the non-gliding arboreal genera Sciurus, Pseudocheirus, and Hemibelideus. Both functional and evolutionary aspects of the problem are presented. The gliding membranes with their associated musculature and cartilages and the musculature and bones of the pectoral appendages were dissected in the following fluid-preserved genera: Glaucomys, Pteryomys, Iomys, Petinomys, Petaurista, Anomalurus, Cynocephalus, Schoinobates, Petaurus, and Acrobates. Descriptions and figures of these anatomical structures are presented. Measurements of the forelimb and its parts were taken and are presented primarily as ratios. Despite the tendency in recent years to split the Petauristinae into a number of groups on the basis of evidence from teeth, bacula, ear region, and immunology, evidence from the musculature of the patagia and pectoral limb, the osteology of the pectoral limb and the presence in all genera of a styliform cartilage with nearly the same structure suggests that this group may be monophyletic. The petauristines share 72(67%) osteological characters out of 109 studied that are different from Sciurus. All gliders share only 23% of the same characters. Within the petauristines studied, various stages of primitive (Glaucomys) versus derived (Petaurista) characters are elucidated. Osteological characters which may prove useful in determining whether or not a fossil sciurid is a glider are listed. The anatomy of the gliding phalangers and that of Pseudocheirus shows that all of the gliders could have evolved from a Pseudocheirus-type ancestor. The anatomy of Hemibelideus suggests that it should be considered as a separate genus rather than as a subgenus of Pseudocheirus. Schoinobates is convergent with the rodent genus Anomalurus in the presence of a styliform cartilage which articulates with the olecranon process. Osteological characters which may prove useful in determining whether or not a fossil phalanger is a glider are listed. Special functional adaptations found in the pectoral limb of the gliding genera are: increased size of the M. supraspinatus providing increased force of outward rotation of the humerus at the shoulder joint, increased length of insertion of the pectoralis major providing a brace for the forelimb against the force of air hitting the ventral surface of the patagia, the metacromion of the scapula and the greater tubercle of the humerus act as a locking mechanism in the shoulder joint, and the coracoid process of the scapula and the muscles of the rotator cuff brace the shoulder joint. The patagia of the gliders are edged with rope-like muscles which help maintain the shape of the membranes by isometric contraction. While not gliding, relaxation of these muscles and contraction of the humerodorsales I and III and of the flexor carpi ulnaris (Petauristinae) helps to pull the membranes and styliform cartilage toward the body. No mechanism for pulling the styliform cartilage of Anomalurus toward the body could be elucidated. During the glide, the humeroventralis, humerodorsales, and the transverse muscles are probably used to control the amount of upward billowing in the membrane caused by the force of the air and allow the animal to change its angle of attack during the glide. The bones and muscles of the pectoral limb are more robust in the non-gliders indicating they climb up and down trees more frequently than do the gliders. The osteological and myological characters of Hemibelideus indicate that the members of this genus are probably capable of limited gliding.

Ontogenetic niche shifts usually occur concurrently with a change in developmental stage and likely evolved as a strategy to reduce mortality and optimize growth at each developmental stage. The optimal shift point may be flexible, however, and may be influenced by environmental cues. In this dissertation I address the following three objectives: (1) Compare habitat preferences and dispersal duration and timing of early life stages of shortnose sturgeon from a northern (Connecticut River, MA, USA) and a southern (Savannah River, SC, USA) river, (2) Determine the effect of three temperature regimes on the timing and pattern of downstream dispersal of shortnose sturgeon larvae, and (3) Link changes in morphological development with ontogeny of behavior in shortnose sturgeon. During the period of yolk-sac absorption, fish from the Connecticut and Savannah Rivers which were reared at the same temperature selected cover and dark habitat, sheltering under rocks and preferring darkness and black substrate. Once fish began feeding exogenously, they switched rapidly to a preference for open, bright habitat, emerging from rocks and selecting illuminated areas and white substrate. Connecticut River fish moved downstream for 6 days (days 7–12 after hatching) beginning immediately after feeding began. However, Savannah River fish had a longer dispersal with multiple, prolonged peaks and fish continued a low level of downstream movement for the whole larval period and as early juveniles (at least until day 62). The differences in dispersal between Connecticut and Savannah River fish, however, were expressed under the same laboratory conditions, including temperature. Thus, genetic differences between the populations do exist and conservation strategies should consider this. In tests with Connecticut River fish to determine temperature effects on dispersal pattern, rearing fish at 10°C delayed the onset of dispersal, but increasing the temperature (15 and 20°C) produced a dispersal with multiple peaks, rather than simply shifting the peak to a younger fish age. Fish were morphologically similar when they began dispersing, regardless of river or temperature. Colder temperature caused development to slow and fish to delay beginning dispersal. These results show dispersal of shortnose sturgeon early life stages is influenced by river temperature.