220 INVERTEBRATE PHYSIOLOGY 



of glucose to chitin. Moreover, since the latter process is of importance in 

 preparation for the molt, it is conceivable that the diabetogenic hormone 

 and the molt-inhibiting hormone are identical. This view is further sup- 

 ported by the observation of Schwabe, Scheer, and Scheer (1952) that 

 eyestalk removal is followed by an increase in the glycogen content of the 

 epidermis in stage C in Panulirus japonicns. 



The metabolism of lipids has been much less well studied in decapods 

 than the metabolism of carbohydrates. Smith (1915) observed decreases 

 in the lipids of blood and hepatopancreas immediately following a molt. 

 Paul and Sharpe (1919) found that the fat content of the digestive gland 

 increases as the molt approaches, while the content of phosphatides de- 

 creases. Renaud (1949) followed the content of total lipids and various 

 lipid fractions through the intermolt cycle of Cancer pagurus. Lipid con- 

 tent of the digestive gland falls after a molt until feeding begins in stage 

 Ci. It then rises continuously until feeding stops in stage Di, when it begins 

 to fall again. This suggests clearly that lipids constitute a primary store of 

 energy in the normal periods of inanition in the intermolt cycle. However, 

 Neiland and Scheer (1953) found no decrease in lipid content of whole 

 stage C specimens of Heinigrapsus nndns during 23 days of fasting. Re- 

 moval of the sinus gland provoked a marked decrease in lipid content of 

 fasted animals. This suggests a hormonal control of lipid metabolism ; but 

 further studies are needed. 



Renaud (1949) found that the fatty-acid content of the hepatopancreas 

 of Cancer pagurus follows the same pattern of variation in the intermolt 

 cycle as does the total lipid. Phosphatides, cholesterol, and unsaponifiable 

 lipid follow a similar pattern, but the amount of change is much less. As 

 a result, the ratio of phosphatides to total lipids is maximal at the begin- 

 ning of feeding ( Cx ) , minimal at the end of the feeding period ( D^ ) . Histo- 

 chemical studies with Panulirus argus (Travis, 1955) generally agree with 

 the quantitative studies, indicating an accumulation of lipid in the hepato- 

 pancreas during stage Ci and its utilization in stage D. In stage D, fatty 

 acids and cholesterol appear in the integumentary tissues as well, and 

 Travis (1955) suggests that they function in the formation of the integu- 

 ment. 



It is remarkable that, in view of the many studies of the hormonal con- 

 trol of color change, so little attention has been paid to metabolism of the 

 pigments, and particularly of carotenoids. Schwabe, Scheer, and Scheer 

 (1952) found a steady deposition of lipochromes, presumably carotenoids, 

 in the digestive gland throughout stage C in Panulirus japonicus, parallel- 

 ing the pattern observed in other species for other lipids. Eyestalk removal 

 had no effect on this deposition, or on the utilization in stages B or D in 

 males. In females, on the other hand, eyestalk removal resulted in a dis- 



