THE WHEEL ANIMALCULES (ROTATORIA) 591 



23 (22) Cuticula without many transverse folds. . Notommata Ehrenberg. 

 Many species. 



Representative species (Fig. 878). . . Notommata aurita Ehrenberg. 



(Fig. 88 1) N. torulosia Dujardin. 



(Fig. 857, A and B, page 556). 



N. truncata Jennings. 



24 (21) Very large, thick-bodied forms Copeus Gosse. 



Corona extending far on ventral surface. Few species. 



Representative species (Fig. 857, C, page 556, and Fig. 864, page 565). 



Copeus pachyurus Gosse. 



25 (20) With three eyes Eosphora Ehrenberg. 



One large eye on brain; others small, in front. Few species. 



Representative species (Fig. 879). . . Eosph ora digitata Ehrenberg. 



26 (6) Two or four long bristle-like antennae on corona. Foot present or 



absent Family SYNCHAETIDAE . . 27 



Open- water rotifers; bodies short; foot short or absent; corona as broad as the broadest 

 part of the body, consisting mainly of a row of large cilia about the circumference. 



27 (28) Auricles present Synchaeta Ehrenberg. 



Body usually conical, largest at the head; foot short, rarely absent. About a dozen species. 



Representative species (Fig. 883). . . Synchaeta stylata Wierzejski. 



(Fig. 880) S. tremula Ehrenberg. 



(Fig. 884) . . 5. baltica Ehrenberg. 



28 (27) Auricles absent. No foot 29 



29 (30) With lateral oar-like swimming appendages. . Polyarthra Ehrenberg. 

 One species only (Fig. 882). . . . Polyarthra platyptera Ehrenberg. 



30 (29) Appendages lacking Anarthra Hood. 



One species only (Fig. 885) Anarthra aptera Hood. 



31 (5, 64) Lorica always present. Corona small, not so broad, as a rule, as 



the broadest part of the lorica. Suborder Loricatina . . 32 



Foot present, short, not ringed; ending in two toes, or rarely one. 



32 (47) Lorica divided into plates by longitudinal furrows 33 



