THE WATER FLEAS (CLADOCFRA) 



701 



54 (55) Head and valves strongly reticulated and covered with jk. 

 short spinules Ccriodaphnia ncuuthin.i R,, 



General shape rotund with well-developed spine. Head much dc-prrssc*!, n.' .„ 



front of antennules or at vertex. Antennules short and thick with sc'iisc--hair'nr {. 



abdomen narrow, much like quadrannula, with 7-0 anal spines. Claws dcnticulau . ..,,, ict 



in the proximal two-fifths of the claw obviou.sly longer than ihc remainder. CoJor whjtith- 

 transparent to very dark. Length, 9. to i.o mm., $ unknown. 



Manitoba, in weedy slough. 



.p-¥ 



Fig. 1080. Ceriodaphnia acanthina. FiG. 1081. Details of vilve. much enlwiceil. 



(54) Valves not spinulated 56 



(57, 62) Post-abdomen abruptly cut into near apex, serrate alwvc, 

 spines below Ceriodaphnia mcgalops *><.v^ i>f>! 



Head angulated before antennules; valves striatwl. Anten- 

 nules with sense-hair near apex. Post-alxlomcn J)n»a<i. with 

 an angle near apex, cut into below angle, limly x-rralr al«)ve 

 and with 7-9 slender anal spines be-low. (Maws not pectinate. 

 Length. 9. io-i-5 mm.; $ , 0.6-0.8 mm. 



Widely distributed but not common. 



Fig. 1082. Ceriodaphnia ttugalcps. 



57 (56, 62) 



58 (59) 



Post-abdomen not cut into; of ordinary form. 



;8 



Fornices projecting into spinous processes. F^yc small. 



Ceriodaphnia lamslris Birgc 1803 



Head angulati^l in front <»f an- 

 tennule; vertex with t'inc spinulc*. 

 lornices very briKid. tri;ini:uUr; 

 with spines at tip. Valxt-^ with 

 stout, short pi»sterit»r sj>inc. Munr- 

 times divide*!, but ">i .IK «ith 

 ^-4 s|)inules. Pt»st ..' ' • 



Quadrjiigult}. ' U! 'f 



yellow. trans|xircnl. i.<n(.'tn. V. 

 o.S-o.(; mm. 



Wisconsin, Michigan; limnetic 

 in lakes. 



Fig. 1083. CmodapkmU iauilni 



