THE WATER FLEAS (CLADOCI-RA) jic, 



130(131) Dorsal margin much arched Irn'/>rra5 /wrp.;, Baird 1H35 



Eye anfl ocellus m-ar niarKin ko»- 

 trum acute. Kleven lo twelve fcruufn o( 

 fine spinules on {tost-alMlomen. l^m^h. 

 9. to o.S mm.; ^ . to 00 mm 



Common ever>where. amoni; »c*t|», 

 ill relatively oinrn water; not in muddy 



IKJOIS. 



u;. 1 121. Acrop<rui hjrpct. 



0.1 MM. 



131 (130) Dorsal and ventral margins nearly straight. 



Acropcriis angiistiitus Sars 1863. 



Crest larger than in A . harpar; eye and 

 ocellus removed from margin and rostrum 

 obtuse. Length, 9. to o.g mm; ^. 0.6 

 mm. 



Common in similar situations to prctc*!- 

 ing species. Transition forms l)etwem these 

 species may be found and ver>" prolxibly 

 they should be united. 



Fig. 1 1 22. Acroprrui jnKuiliiJui 



0.1 MM. I « 



r32 (124, 129) No crest 133 



^33 (134) Valves not tumid; post-abdomen broad. 



Alonopsis Sars 1S62 



/T'i 



tii^ 



General form resembling Acroprrus but less com- 

 pressed and without crest. Keel of InSnim m^w'^mtr 

 or small, almost triangular. Vahi - I 



but striae often inconspicuous. 1 

 broad; with well-develoix^i mar,: \ 



pairs of feet, the last very small. S **'ii' "*"*' 

 characters. Color yellow. 



Fig 1123. a, Alonopsis flonfala: h. AUfmoptii 



(MU'T n.v.littic 



0.1 MM. 



J 0.1 MM. 



133^^(133^) 15-17 marginal denticles [hmo psis chn^ata Surs i^i. 



Minute tooth at infero-posteal angle of valves. Post-abdomen with lateral f.^. i. I- Im.Mh. 

 9 , ca. 0.8 mm. 

 1336(133^0 About II marginal denticles. . Alonopsis aurcohi IhKAiiiki.i:. 



No lateral fascicles or infero-posteal tooth. Ix-ngth, 9 ^■'^- '/^ TI^.^MinT*""" ^^ 

 species in margins of lakes and ponds among weeds. Rare; rei)ortcd only from Maine 



