IOWA ACADEMY OF SCIENCES. 



173 



West Okoboji, fifteen to twenty 

 feet below surface 



East Okoboji, surface 



Spirit Lake, ten to fifteen feet 

 below surface 



Raccoon River, Adel, lowa. 



f Dapbnella bracbyura. 

 Daphnia kal., variety retrocurva, 

 Simocepbalus serrnlatus. 

 Ceriodapbnia consors. 

 Eurycercus lamellatus. 

 Danbevedia setiger. 

 Cbydorus spbaericus. 

 Cbydorus globosus. 

 Camptocercus rectirostris. 



Sida crystallina. 

 Ceriodaphnia reticulata. 

 Ceriodaphnia consors. 

 Dapbnia kal., variety retrocurva. 

 Daphnia hyaliaa 

 Macrothrix laticornis. 

 Eurycercus lamellatus. 

 Cbydorus spbaericus. 

 Leydigia quadrangalaris. 



\ Dapbnella bracbyura. 



• Dapbnia kal. , variety retrocurva^ 



1 Cbydorus spbaericus. 



r Ceriodapbnia reticulata. 

 J Scapboleberis mucronata. 



Raccoon River at Sac City. 



Iliocryptus sordidus. 

 Pleuroxus denticulata. 



Scapboleberis mucronata. 

 Simocepbalus serrulatus. 

 Cbydorus spbaericus. 

 Pleuroxus denticulatus. 

 t Alona sp? 



THE ANATOMY OF SPH^RIUM SULCATUM LAM. 



BY OILMAN A DREW. 



For a number of years the embryology of the Cyrenidas has 

 been attracting considerable attention, but little has been 

 added to our knowledge of the general anatomy since Dr. 

 Franz Leydig's publication in 1855 (No. 5), who recorded such 

 anatomy as could be made out from young and rather trans 

 parent specimens.* 



It is my present intention to continue the work here begun 

 on Sphasrium to a comparative anatomy of the Cyrenidse, but in 



*I find a reference to a paper by Temple Prime, entitled: Notes on the Anatomy of 

 the Oorbiculida; and Translation from the Danish of an article on the Anatomy of 

 Oyclas by Jacobson. Bui. Museum Comp. Zool., Cambridge, Vol. V. This volume 

 unfortunately is not to be found in the reference libraries of Baltimore. 



