THE WATER FLEAS (CLADOCERA) 711 



96 (99) Hepatic ceca present; post-abdomen bilobed; antennary setae 



9 ^lf- 97 



97 (98) Post-abdomen very large, with few spines. . Grimaldina Richard 1892. 



Sole species . Grimaldina brazzai Richard 1892. 



FIG. 1 1 06. Grimaldina brazzai. 



Body compressed, somewhat quad- 

 rangular, with all margins of valves 

 slightly convex. Post-abdomen enor- 

 mous, much compressed, roughly semi- 

 elliptical in form; the pre-anal portion 

 divided by a notch into two parts, of 

 which the anterior is the smaller; a 

 long spine in the notch which marks 

 junction of anal and pre-anal parts; on 

 anal part two lateral rows of small, 

 slender spines, about 7 in anterior, 

 and 5 in posterior row. Claws small, 

 denticulate, with i small basal spine. 

 Ephippium rounded-q uadrangular; 

 egg-chambers reniform with concave 

 sides toward each other. $ (South 

 America) small, like immature 9 ; an- 

 tennuleswith 2 basal sense-hairs; small 

 hook on first foot. Color reddish- 

 brown. Length, to 0.9 mm.; $, 

 0.5 mm. Louisiana; weedy pools of 

 clear water. 



98 (97) Post-abdomen moderate; numerous small spines on pre-anal part, 

 clusters of hairs on anal part. . . Wlassicsia Daday 1903. 



Sole American species. 



Wlassicsia kinistinensis Birge 1910. 



with large 

 , 0.8 mm.; 



Form oval, not com- 

 pressed. Valves crested; 

 with spines on ventral mar- 

 gin; marked by very deli- 

 cate transverse striae which 

 anastomose, forming fine 

 vertical meshes. Olfactory 

 setae subequal. Two 

 rounded projections at base 

 of labrum on ventral sur- 

 face of head. Labrum with 

 strong conical projection 

 pointing backward and a 

 second projection just in 

 front of small terminal 

 lobe. Post-abdomen with 

 fine spines and hairs. Ab- 

 dominal setae very long, not 

 set on projection. Claws 

 with very small basal 

 spines. Five pairs of feet; 

 branchial sacs on all legs. 



antennule; small keel on labrum; hook on first foot. Color yellow. Length, 



$ , 0.4 mm. Marsh at Kinistino, Manitoba. 



O.I MM. i i 



FIG, 1107. Wlassicsia kinistinensis. 



99(96) No hepatic ceca; post -abdomen various 100 



