THE WATER FLEAS (CLADOCERA) 



737 



243 (238) Claws with 2 basal spines; posterior mar^'in of valves excised near 

 infero-posteal angle 



244 



244 (245) Post-abdomen fairly long; angled at apex; valves reticulated and 

 with fine striae Honclla excisa (VischLT) iSs.\. 



1165 



Alonella excisa. Entire specimen and details of 

 markings of valve. 



Cicncral apixrarancc Pl/^u- 

 rorM5 like. Rostrum moder- 

 ate to lon^, never as pro- 

 lonsed as in A. ro strata nor 

 recur\e<l; longer in southern 

 forms. Infero-i>ostcal angle 

 marked, sf>metimes iinxiuce*! 

 into a fxjint; i)osterior mar- 

 gin al)ove it excisctl. si>mc- 

 times crenulatefl. Post ab- 

 domen long, narrow, not nju'- 

 rowing much toward apci; 

 apex angled; with al)out if- 

 10 small marginal denticles. 

 Color yellow to bnjwn. 

 Length. 9, to 0.5 mm.; ^, 

 0.28 mm. 



Not uncommon in all lo- 

 calities; in weedy pools and 

 lakes. 



245 (244) Post-abdomen short; 



rounded at apex; valves without fine striae. 

 Alonella exigua (Lilljeborg; 1853. 



Much like preceding sr>ecies but smaller. About 6-8 small 

 marginal denticles. Color yellow, not ver>- transparent. 

 Length, 9.0-3Smm.; ^, 0.28mm. 



Maine, Wisconsin, Michigan; rare. 



Fig. 1 166. Alonella exigua. 



0.1 MM. 



■*4 



246 (121) Eye and ocellus very large; antennules project far beyond rostrum. 



Dadaya Sars 1001. 

 Sole species Dadaya nidcrops {D^i.\:iy) iSq8, 



Form rounded-oval; not a)mpresseti. Head 

 small, much dcpres,se<l; tumid alxjve eye; ros- 

 trum short and broad, .\ntennules long, mtxl- 

 erately stout, projecting far U-yond rostnim. 

 Post-abdomen of nKnlerate si/^, comprrw>l. 

 somewhat broadeni>d l>ehind anu.s slightly 

 narrowing toward ajx-x; angle roundcti; al>out 

 14-18 marginal denticles. Claws small, one 

 small basal spine. Kye very large, with few 

 lenses; ocellus nearly as large, crowtiixl d»»wn 

 into rostrum. X unknown. Color dark 

 brown. Length. 9 . '■i*- 0-< f""^- 



A single siK-cimen of this s|»edes was found 

 in a collection from a wectly ikx)I at Smilb- 

 ville, Texas. 



Fig. 1167. Dadaya m^ropi. 



