KEY TO THE ENTOMOSTRACA OF COLORADO 



279 



45 (42) Claw of post-abdomen without pecten. Anal spines increasing much 

 in length toward end of series 46 



Fig. 25. — Daphnia puki 



Digestive tract 

 Abdominal processes 



, crested female: b, male. 



Brood- chamber 



Heart 



Abdominal clows 



Post' abdomen 



Fig. 26. — Daphnia pulex. Female bearing 



eggs. 



46 



(47) Head not helmeted. Form of body very much like that of pulex and 

 a very similar series of varietal forms exists. 

 Length up to 2 . o mm. 



Daphnia longispina O.F.M. 



From western edge of plains to moderately high mountain 

 lakes; most abundant in mountab lakes of intermediate eleva- 

 tion; 5,2oo-ii,35oft. [Widespread, 

 essentially cosmopolitan.l 



\dx. longispina form FriedeWRait' 

 wig. A small form with spine very 

 short or wanting. Silver Lake; zo,300 

 ft. First time recorded in America. 

 [Reported from near Berlin.] 

 Fig. iS.—Daphnia longi- 

 spina var. longispina form 

 Friedeli. 



Fig. 27. — Daph: 

 Post-abdomen. 



longispina. 



