704 



FRESH-WATER BIOLOGY 



68 (69) Post-anal spines fewer than 8. 



Animal small, about 0.5 mm. long. 

 Moina micrura Kurz 1874. 



Small, transparent; head relatively very 

 large; deep cervical sinus; supra-ocular de- 

 pression small or absent. Terminal portion 

 of post-abdomen small with 4-6 spines and a 

 much longer bident. Claws pectinate. Male 

 imknown. Length, 9 j 0.5-0.6 mm. 



Illinois, Arkansas, Louisiana. 



Fig. logo. Moitia micrura. 



69 (6S) Post-anal spines 8 or more. Animallarger, about I. o mm. or more. . 70 



7° (75) Supra-ocular depression present; claws pectinate; no flageUum on 

 first foot of male. . . ... ... 71 



71 (72) Two ephippial eggs; antennules of male with sense seta in middle. 



Moina brachiata (Jurine) 1820. 



Body stout, heavy; greenish, not transparent. Head ordinarily much depressed, so that 

 vertex often Ues almost on level of ventral margin of valves. Deep supra-ocular depression. 

 Valves faintly reticulated. Post-anal spines 7-11 besides bident; claws pectinate. Anten- 

 nules of $ with 4 hooks; iirst foot without flagellum. Length, 9 , to 1.5 mm.; $ unknown in 

 United States. 



Wisconsin, Nebraska, Missouri; no doubt widely distributed. In pools. 



0.2 MM. I, 



Fig. 1091. Moina brachiata 



72 (71) One ephippial egg , 73 



