ENTOMOSTRACA OF MINNESOTA. 171 



the secondary teeth of the claws of the post- abdomen seemed to be 

 absent, though in G. reticulata three to five are constantly present." 

 Professor Birge now identifies this species with G. reticulata. 



Ceriodaphnia punctata P. E. Mueller. 

 Plate XLI, Fig. 13. 



Head depressed, rounded at the end, not angulated, ornamented 

 with minute spines within the hexagonal areas. Fornices slightly 

 prominent, either smooth or spiny; antennules very long; shell rotund, 

 reticulated; post-abdomen of medium size, width nearly uniform, 

 truncate below at an obtuse angle; anal spines large, increasing 

 toward the end; claws smooth. Length 0.7 to 0.9 ram. 



Found as yet only in Scandinavia. 



* Ceriodaphnia laticaudata P. E. Mueller. 

 Plate XLI. Fig. 22. 



Ceriodaphnia quadrangula — Sars (fide Mueller). 

 Ceriodaphnia consors — Birge. 



Head small, depressed, rounded at the end, not angulated; fornices 

 prominent; shell roundish, or sub- quadrangular, moderately reticu- 

 lated, antennules rather large; post-abdomen broad, narrowed from 

 the middle to the end; the nine or ten small anal spines nearly equal; 

 claws large and smooth. In P. E. Mueller's time males unknown. 

 Length 1.0 mm. Specimens 0.6 mm. long from Minnesota agree in 

 most respects, but the reticulation is very marked and irregular and 

 the terminal claws are pectinate. This form constitutes a transition 

 to the next. 



A species related to G. laticaudata, but only half the size, was found 

 in Clarke's lake, a small but very deep pool, containing a fauna like 

 that of the Great Lakes. The appearance is like the small form 

 alluded to under that species, but the claws are smooth, the head is 

 slender and strongly angled behind the eyes, and the antennules are 

 of rather large size. The fornices are not very prominent. The shell 

 is large-reticulate and the abdomen is large and obliquely truncate, 

 the anal teeth being very large and strongly curved. The only indi- 

 viduals seen were ephippial females measuring 0.55 mm. This may be 



* Ceriodaphnia consors Birge. 



Plates XLII, Fig. 4; XLIV, Figs. 5, 6. 



This differs from G. laticamlata in one or two points, being about 

 one-half tke size and having fewer caudal teeth. Birge says the abdo- 



