188 ^^0 URGES OF ENERGY IX ANAEROBIOSfS 



Artlii'opods. Stott (1932) found that the blood 

 sugar of crabs increased considerably when they were 

 deprived of oxygen. Since it is unlikely that large stores 

 of simple sugars exist anywhere in the body of these ani- 

 mals, the sugar observed was probably derived from a 

 polysaccharide reserve. Boyland (1928) demonstrated 

 that the abdominal muscles of decapods convert glyco- 

 gen into lactic acid during fatigue, in the state of rigor 

 and when they are placed in buffer solutions. 



It seems, on the whole, that decapod crustaceans never 

 accumulate large quantities of glycogen and there are 

 some indications that in many instances the substance 

 serves merely as a source of the carbohydrate component 

 required for chitin formation (Bernard, 1879; Vitzou, 

 1882; von Schonborn, 1912; Verne, 1924; Dorman, 1928; 

 Baumberger and Dill, 1928; Chaigne, 1934; Eegan, 1944), 

 rather than as an energy reserve. This does not, however, 

 exclude the possibility that it may take on the latter role 

 when the oxygen becomes scarce or is lacking entirely. 



The crustaceans that exhibit the most marked resist- 

 ance in anaerobic conditions {Cyclops species, Cirripedia) 

 have, as far as the present writer is aware, not yet been 

 studied for their glycogen content. 



Glycogen storage is common amongst insects though 

 large amounts of it are found only in rare cases. One 

 of these rare cases is that of the larvae of the honey 

 bee. Data (some of them quantitative) for a variety of 

 insects are presented by Bataillon and Couvreur (1892), 

 Straus (1911), Kaneko (1924), Dinulescu (1932), de 

 Boissezon (1932), Ditman and Weiland (1938), Paillot 

 (1938), Yeager and Munson (1941), Babers (1941), Wig- 

 glesworth (1942) and others. 



It has been shown conclusively in a number of instances 

 that glycogen is utilized by insects for anaerobic proc- 

 esses. The parasitic larvae of Gasterophilus intestinalis 

 consume 1.33 g. glycogen per 100 g. body weight per 24 



