STATE GEOLOGIST. 63 



Sp. 1. Daphnia longiremis, Sars. 



Hyaline, compressed, seen from the side, rounded, lower margin 

 strongly arched; spine long, straight, oblique. Head rounded, 

 lower margin nearly straight, ending in a beak directed downward, 

 acute anteriorly. Eye small. Antennae very long. Length 1 mm. 



The abdomen is said to be similar to that of D. longispina. From 

 the brief description given by Sars it would appear that this spe- 

 cies is characterized by a rounded and uncrested or slightly crested 

 head. Though imperfectly described, it is here mentioned to direct 

 attention toward any such species as may be found in America. 



Sp. 2. Daphnia cristata, Sars. 



Compressed, long. Head acute in front, strongly crested, lower 

 margin nearly straight. Dorsal line of body little curved, spine 

 long in the young, strongly curved. Head of male smaller, flagel- 

 lum of antennule twice as long as the setae; first foot well clawed. 

 Length of female 1.33 mm. 



Sp. 3. Daphnia cucullata, Sars. 

 D. JjRrolinensis, Schoedlek. 



Very like the above, but the margin of head is not straight be- 

 low, is, however, extremely variable and ends in a sharp angle. The 

 eye lies nearly midway between the heart and the end of the head 

 and near the lower margin. The two anterior processes of the 

 abdomen are united for most of their length. The flagellum of the 

 male antenna is about as long as the terminal setae. 



D. apicata^ Kurz, seems to be a large variety lacking the sharp 

 spine of the head. In the main it agrees quite well. Although the 

 post-abdomen is broader than figured by Mueller, the number of 

 teeth corresponds with Sars' description. 



Sp. 4:. Daphnia kalberg-ensis, Schoedler. 



(Plate U. Figs. 1—3). 



Form oval, spine long. Head high, compressed, enormously 

 elongated, beak obtuse. Eye small. Abdominal processes not 

 united. Caudal claws ornamented with small setae. Antennae of 

 male with a short flagellum. Length of head nearly equal to that of 

 body exclusive of spine. 



i). vitrea of Kurz seems not improbably a varietal form of the 

 above though the crest is lower, the size is less and the post-abdo- 



