THE WATER FLEAS (CLADOCKR 



\) 



»7 



Only one American species. 



Euryccrcus lanidlatus (U. V. Muilcr; 1-81 



Body stout, heavy. i'oM alxlomm vit>- Urir«. 

 flattened, general form (|ua<lraiiK'ular; aruis t«-nnin*l. 

 in depression; (l<)rs.il niarK'in. with \.r\ : .:;i.r<>u» 

 — over 100 — saw like ti-fth. C'lav. • m* 



projection, with 2 basal spines and <: Sit 



pairs of feet. Inte.stine with hejxaii. . • . .1 .... 1 ii^j- 

 volution. $ Uke yoiuiK 9 ; h.x.k on tir>t fcit; v%% 

 deferens opens at base of tlaw on ventral (anterior) 

 side. Color yeliowish-hrown. oia(iue. Ix-nKth, 9. 

 to 3.0 mm. or more; ^ . to 1.4 mm. '1'he Luxcst 

 member of the family. Found ever>-where; in ijcr- 

 manent pools or margins of lakes among weeds. 



Fig. 1 1 18. Eurycercus lameUdJiu. Poa-.M^iumrn. 



119 (118) Anus on dorsal side of post-abdomen, whose post-anal portion l)cars 

 denticles. No hepatic ceca. Two siminiiT eggs; one 

 ephippial egg. $ with strong hook on first fixjt. 



Subfamily Chydorin.\e . . 120 



120(247) Eye present i.'« 



121 (246) Eye and ocellus of ordinary size; antennulcs do not [)rojccl Ix^yond 



rostrum, though olfactory setae may 122 



122 (171) Posterior margin of valves not greatly less than ma.ximum height, i:^ 



No species of Pleuroxus belong in this section, though s«)me individuals of lys and iw m.»y 

 seem to do so. 



123 (135) Body compressed; claws with secondary tooth in middle. 



124(129,132) Crested; post-abdomen narrow,' with marginal and Liicral 



denticles '^S 



1 Terms denoting relative size are to be unclcrstcHHJ with reference to llic s*-clit)n in 

 which they occur. 



