70 LABORATORY STUDIES IN ZOOIAHIY 



E. With both ciha and cirri. 

 F. Body not very flexible. 



G. Three caudal or posterior cirri Stylonychia 



GG. No caudal cirri Histrio 



FF. Body quite flexible; caudal cirri undeveloped. . . .Oxylricha 

 EE. With cirri only. 



F. With four caudal cirri Euplules 



FF. With seven to nine caudal cirri Uronychia 



CC Sessile, enlarged oral cilia winding to right, usually forming an 

 almost complete circle. 

 D. Solitary, attached by a retractile stalk; body bell shaped; circle 

 of strong ciha about elevated disc of free (broad) end. Vorhcella 

 DD. Individuals forming arboroid colony; bodies bell shaped. 

 E. Stalks retractile. 



F. Individuals contracting independently Carchesium 



FF. Individuals all contracting together Zouthamium 



EE. Stalks not retractile Epixtylis 



BB. Mouth not surrounded by a spiral zone of large cilia. 



C. With a sculptured shell about a barrel-shaped l)ody Colcps 



CC. Without such a shell. 



D. Cilia not uniform over body. 



E. Prominent cilia confined to one or two bands. 



F. With two circles or crowns of long cilia, one near the 

 anterior end, the other in the region of the equator of the 

 ovoid body; nipple-like elevation bearing mouth and 

 arising from the center of a flattened anterior end 



Didinium 

 FF. Two zones of strong cilia about body; cell somewhat 

 cylindrical, with a constriction slightly behind the mid- 

 dle; a prominent tuft of fused cilia at the posterior end 



Urocejitrum 

 EE. Cilia only on ventral surface; cirri not present. 



F. With a long neck; body oval, ending in a short tail. Lionotus 

 FF. With the anterior end hooklike; body inflexible, ventral sur- 

 face flattened and showing ciliated ribs; mouth on the left 

 anterior edge, at the bottom of a slitlike peris tone Loxodes 



DD. Cilia uniform over body. 



E. Mouth terminal or nearly so; no proboscis. 



F. With no evident gullet; body elongate, anterior end nar- 

 rowed and flattened into a neck which is obliquely trun- 

 cate Spathidiuni 



FF. With more or less evident gullet. 



G. Form flask shaped; with a short or long, highly con- 

 tractile neck, and a rounded posterior end. .Lacrymaria 

 GG. Form spherical to ovate; without a neck; cytopharynx 



long Prorodon 



EE. Mouth somewhat posterior to anterior end; sometimes with a 

 proboscis. 

 F. With proboscis in front of mouth. 



