. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ANAEROBIC METABOLISM OF SNAILS 271 The next to the last column of Table III shows that in Lymnaeidae and Physidae a major portion of the carbon dioxide excreted was probably of inorganic origin, having been liberated from bicarbonate during glycolysis leading to lactic acid. In Lymnaca natolcnsis even more lactic acid was found than corresponded to the carbon dioxide excreted. In all other species the amount of CC>2 due to lactic acid was only moderate. In view of the absence of information concerning the other end produc
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ANAEROBIC METABOLISM OF SNAILS 271 The next to the last column of Table III shows that in Lymnaeidae and Physidae a major portion of the carbon dioxide excreted was probably of inorganic origin, having been liberated from bicarbonate during glycolysis leading to lactic acid. In Lymnaca natolcnsis even more lactic acid was found than corresponded to the carbon dioxide excreted. In all other species the amount of CC>2 due to lactic acid was only moderate. In view of the absence of information concerning the other end products of the anaerobic carbohydrate metabolism, the question of whether or not the remaining COo was also of inorganic origin or whether it represented true respiratory COi> must remain unanswered at the present time. • AUSTRALORBIS GLABRATUS A—AABIOMPHALARIA BOISSYI. 20 25 30 35 40 45 DAYS OF STARVATION FIGURE 1. Influence of starvation on the anaerobic carbon dioxide production of aquatic pulmonate snails. Twelve well-fed specimens of Australorbis ri lab rat us and 6 specimens of Biomphalaria boissyi were used. They were exposed on specified days to 6 hours anaerobiosis. Between the anaerobiosis periods the snails were kept starving in aerated, dechlorinated tap- water. The determinations were continued until the last snail of each group died. The figure shows the individual and the mean values (small and large symbols respectively). During starvation (Fig. 1) the rate of anaerobic CO- production fell progres- sively but the decline was, on the whole, less pronounced than in the case of the previously studied aerobic metabolism (von Brand, Nolan, and Mann, 1948). In several species the specimens used for the CO2 determinations varied rather markedly in size. A study of this material (Fig. 2) shows that in intraspecific comparisons the CO2 production followed the surface law rather well (relative sur- face calculated as weight %), while the same obviously <,lid not hold
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