Daplinia hyalina Leydig. 



Fig. 



1. Outline of female from Lake Minnetonka drawn to the same scale 



as figure 5. 



2. Head of a common form of the above species. 



3. Extreme development of the crest. 



4. Embryo illustrating the early development of the helmet. 



Daphnia kalbergensis Schoedler. 



5. Typical form, from Lake Minnetonka. 



6. A form of the above taken from the same gathering. 



7. Post-abdomen of the above. 



8. Extreme development of head resembling Z). retrocurva Forbes, 



from same gathering as the above. 

 '9. Daphnia dentifera Forbes. Copy from "Aquat. Invert. 

 Wyoming." 



