64 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



shape. Secondary nucleus near the primary nucleus. 

 One contractile vacuole. The animals frequently live in 

 companies but are never colonial. 



Figs. 274-277, 283-286, 291-294, 296 and 298 repre- 

 sent a number of separate t}'^pes of Vorticella found in 

 our waters. It is difficult to arrange them satisfactorily 

 into species, and no attempt will be made in the present 

 . paper to attach specific names to the forms described. 

 Rhabdostyla S. K. 



Solitary, upon a short, not contractile stalk. In other 

 respects like Epistylis. 

 R. hrcvipes CI. & L., Fig. 278. 

 R. sp. (?), Fig. 295. 

 Pyxidium S. K. 



Solitary, with a short stalk ; in other respects agreeing 

 with Opercularia. 

 P. ramosa Stokes, Fig. 290. 

 Epistylis Ehrbg. 



Colonial, the single individuals of the colony standing 

 about the same height. With a stiff branched stalk con- 

 taining a canal, but no muscles ; hence, not contractile. 

 Animals narrow to broad bell form, mostly with a ringed 

 cuticle. 

 E. Uavicans Ehrbg., Figs. 287, 288, 289. The last figure 

 shows that the spiral band makes four circles around the 

 disk. 

 Carchesium Ehrbg. 



Forming richly branched colonies in which the stalk 

 muscles of the single individual are not attached, but end 

 abruptly at the base of the individual stalks, enabling the 

 individuals to contract independently. Animals all alike 

 in size and structure. Ciliated spiral forming about one 

 and a half circles. Nucleus horse-shoe shape, with a 

 small secondary nucleus near by. One contractile vac- 

 uole. 

 C. polypimim Linn., Fig. 299. 

 Zoothamnium Ehrbg. 



Much like Carchesium, but with a common muscle in 

 the stalk, causing all individuals of the colony to contract 

 together. 



