The Life-Cycle of Cladocera. 



425 



(2) as small granules in the cells of the gut (fig. 3) ; and (3) as much 

 larger, irregular-shaped masses in the connective tissue at the sides of the 

 gut and at the bases of the limbs (figs. 4 and 5). There can be no doubt 

 that these bodies are reserve material of the nature of glycogen, because the 

 areas in which they occur are the same as those in which glycogen is known 

 to occur in the higher Crustacea, and they exhibit the same appearance and 

 staining reactions as the glycogen deposits in higher Crustacea. The fact 

 that the so-called glycogen deposits of Crustacea stain so intensely intra 

 vitam, and also after fixation with neutral red, suggests that they are not 

 pure glycogen, or, at any rate, not identical with the glycogen found in the 

 liver of warm-blooded animals, because neutral red does not show any 

 particular affinity for these latter deposits. That they are largely composed 

 of glycogen is shown, however, by their giving the iodine reaction both 

 microchemically and, in the case of the higher Crustacea, after extraction 

 with hot water in a test-tube reaction. 



Fig. 5. — Parthenogenetic female, isolated at 27° C, showing reserve material present 

 almost entirely as subcutaneous glycogen, with a few fat globules in neighbour- 

 hood of ovary. 



It seems that the glycogen deposits in Crustacea consist of glycogen plus 

 some nitrogenous material, probably a proteid derivative, which is responsible 

 for the special affinity for neutral red. Leaving the exact chemical nature of 

 these amylaceous deposits aside, it is to be observed that the pale green 

 translucent individuals of D. pttlex which have been kept isolated at 

 27° C. exhibit practically all their reserve substance in the form of this 



