STATE GEOLOGIST. 61 



S. L Smith finds both in lake Superior, and seems to have no 

 doubt of their distinctness. One of the forms which 1 have seen 

 differs a little from either of the above, and had a different habitat. 

 Kurz has described the male, which has a very short flagellum upon 

 the antennule. A single source for D. galeata was found in a small 

 pool known as Clarke's lake. This is the more remarkable, as this 

 species, which is almost confined to larger bodies of water, is found 

 nowhere else in the vicinage of Minneapolis, while this minute 

 lake, though as deep, perhaps, as any of the largest in the county 

 (say 40 feet), contains a number of forms known otherwise only in 

 the Great Lakes. Kurz's remarks on the specimens collected by 

 him apply equally to these. Were the claws dentate, the animal 

 would pass as D. pellucida. The young have no horn on the head. 

 The spine of the shell is nearly as long as the whole animal in the 

 young. The male of our form is 1.2 mm, long, excluding the 

 spine which measures 47 mm. The flagellum is a very little 

 longer than the sensory setae, and there is a very minute lateral 

 flagellum. A peculiarity of this species is the scattered thorny 

 armature of the spine of the shell. There is but little change in 

 the form of head with age. The form of the last feet is peculiar. 

 The ephippium occupies comparatively a small part of the valves 

 and the spine becomes very short and quite smooth. The sexual 

 period occurs in September and October. 



The above statements regarding D. galeata require a modifica- 

 tion, for in another deep lake the writer has since secured the 

 typical crested D. galeata with even a higher crest than that figured 

 by P. E. Mueller. The head ends in a sharp angle. The single 

 female seen was in company with the rounded variety and numbers 

 of D. kalbergensis, which it resembles in many respects. Oar 

 fauna therefore is quite complete in these remarkable forms. 



( See Plate U. Fig. 6.) 

 Sp. 11. Daphnia clubia, Herrick. 

 (PlateL. Figs. 7, 8.) 



American Naturalist, 1883. 



The life history of this form is insufiiciently known, but there 

 seems no reason for doubting that it constitutes a new and easily 

 recognizable species. It is nearly related to D. hyalina, but the 

 head is strongly crested all round and the eye is withdrawn, in 

 young as well as old specimens, toward the middle of the head» 

 This peculiarity is shared in this degree by no other Daphnia 



