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Mr. G. Smith. 



microscope it was found that the reddish orange individuals owed their colour 

 to the abundance of coloured fat globules present round the gut and ovary 

 and at the bases of the limbs, while the pale green individuals were either 

 entirely devoid of any fat or else possessed a few globules in the neighbour- 

 hood of the ovary. It was shown in a previous paper (6) that by placing 

 living specimens of Cladocera, such as Moina or Dapbnia, into a vessel of 

 water in which a small quantity of neutral red is dissolved, it was possible 

 to distinguish after a few hours certain bodies which took up the stain with 

 great avidity. These bodies which stain intensely intra vitam with neutral 

 red are distributed in three chief situations — (1) as very small granules in 

 the polygonal cells of the chitogenous ectoderm (fig. 1) (in the case of 

 ephippial females the chitogenous cells of the ephippium, which is formed 

 of very thick chitin, contain much larger masses of glycogen, see fig. 2) ; 



Fig. 1. Fig. 2. 



Fig. 1. — Chitinous areas on carapace, representing chitinogenous ectoderm cells, with 



small granules of glycogen stained with neutral red intra vitam. 

 Fig. 2. — Chitinous areas on carapace in region of formation of ephippium, showing large 

 lumps of glycogen, stained with neutral red. 



Fig. 4. 



Fig. 3.— A group of cells from the gut, showing small glycogen granules occupying each 



cell, stained with neutral red. 

 Fig. 4.— Four large subcutaneous glycogen cells from base of limb, showing irregular 

 masses of glycogen in periphery of cell, stained with neutral red. 



