The Life-Cycle of Cladocera. 



431 



obtain the appearance shown in fig. 11. Here the storage cells are seen to be 

 filled with large and numerous fat globules, the only considerable stores of 

 glycogen being found in the connective tissues outside the liver. Three such 

 connective tissue cells with glycogen are shown in fig. 11. Quantitative 

 estimations of the glycogen and fat in the liver and connective tissues under 

 these various circumstances confirm the result obtained by histology, namely 

 that during the moult there is abundance of glycogen (10 per cent.) and very 

 little fat (3 per cent.), immediately after the moult there is very little glycogen 



Fig. 11. — Section through ditto, about mid- way between two moults, when growth 



processes are in abeyance. The storage cells are crammed with fat globules. 

 Three connective-tissue glycogen cells are shown outside the liver. 



(0 - l per cent.) or fat (5 per cent.), and that between the moults there is abun- 

 dance of fat (15 per cent.) and a rather small amount of glycogen (1;5 per 

 cent. (The figures given here are only rough average approximations, but 

 they give a trustworthy idea of the relative proportions of fat and glycogen 

 in the liver under the various conditions.) 



We conclude, therefore, that just as in the Cladocera, so in one of the higher 

 Crustacea such as Carcinus, the period of active growth is accompanied by 

 glycogen- as opposed to fat-metabolism, while the fat-storage in the liver 



