MR. R. GURNEY ON THE LIFE HISTORY OF THE CLADOCERA. 47 
ephippium-formation is most complete, the ephippium is 
a saddle-shaped area of thickened chitin which may or may 
not become darker than the rest of the shell, but which is 
Fig. 2. Daphnia atkinsoni, Baird. 
Ephippial female, x 37. 
Uways marked off by its more pronounced and generally 
mer reticulation. See fig. 2. In some cases, e.g., 
