KEY TO THE ENTOMOSTRACA OF COLORADO 



281 



56 (55) Abdominal claw smooth. Shell markings with double contours. 

 Head inflated in front of antennules. Length, o. 7 mm. 



Ceriodaphnia pulchella Sars 



Twin Lakes; 9,200 ft. To be expected lower. [Distribution about same as reticulata.] 



Fig. 33. — Ceriodaphnia reticulata. 



Fig. 34. — Ceriodaph- 

 nia pulchella. (After 

 Lilljeborg.) 



Fig. 35. — Moina brachiata. 



57 



59 



(54) Head of ordinary size and not depressed. Antennules long and freely- 

 movable Genus Moina 58 



58 (sq) Ephippium with two eggs. Abdomen with one bident and 7-1 1 simple 

 spines. Length, i . 5 mm Moina brachiata (Jurine) 



La Junta; 4,100 ft. In muddy ponds. (Wisconsin, Nebraska, Colorado, Missouri. Europe, except 

 extreme north, to Egypt.] 



(58) Ephippium with one egg and reticulated all over. In other respects 

 very much like preceding species and M. rectirostris. Length, i.omm. 



Moina affinis Birge 



Greeley; 4,600 ft. I" Wisconsin to Louisiana"; Birge.] 



(39) No diverticula at forward end of gut. Antennules large. . . 6i 

 (62) Antennules many-jointed, tapering, and curved backward, with 

 sensory hairs near the middle. Short spine at lower posterior margin of 



each valve Family Bosminidae 



A small family of two genera. 

 Only one species reported from Colorado. Sensory 

 hairs of antennules a little short of the middle. Ab- 

 dominal claw with a basal series of teeth beyond 

 which, to end of claw, is a series of very fine teeth 

 (these latter wanting in other species of the genus). 

 Form of shell exceedingly variable. Length, o . s mm. 

 Bosmina longirostris (O.F.M.) 



La Junta, Boulder; 4,ioo-s,40oft. May be expected in mountains. 

 [Common in America and in Europe from north to south.] 



62 (61) Antennules i-jointed and not tapering. Sense hairs terminal. No 



Fig. 36. — Bosmina longirostris. 



spine at lower posterior margin. 



Family Macrothricidae 63 



