Stokes.l Ob4: [Nov. 5. 



but a very limited portion of the lorica cavity anteriorly, to which it is 

 apparently in no way attached. Among the numerous individuals exam- 

 ined, none have been seen with the zooid completely filling the cavity of 

 the sheath, and but one in which the body even approached the posterior 

 and lateral walls. 



Cyclonexis, gen. nov. (kukIos ; vij^j?). 



Animalcules laterally joined to form free swimming annular colonies, 

 the zooids illoricate ; flagella two, one long, the other short, both vibra- 

 tile ; endoplasm enclosing two laterally disposed color-bands; eye-like 

 pigment specks absent. Habitat — Fresh water. 



This differs from Uvtlla, which it most closely resembles, in the lateral 

 instead of a posterior union of the constituent animalcules, in the annular 

 rather than a spheroidal form of the colony, and in the very diverse 

 length of the two flagella. 



Cyclonexis annularis, sp, nov. (Figs. 8, 9). 



Colony composed of from ten to twenty zooids, the posterior extremi- 

 ties of the constituent animalcules in young and small clusters occasion- 

 ally in contact, in older and larger colonies remote, leaving a central 

 more or less circular space ; bodies obovate, compressed, about twice as 

 long as broad, obtusely pointed anteriorly, rounded and narrowed posteri- 

 orly ; long flagellum equaling or exceeding the body in length, the short 

 appendage about one-half as long, usually convoluted spirally; contrac- 

 tile vesicle double, small, spherical, located in the anterior body-half, near 

 one lateral border; color-bands yellowish. Length of body T sVff to ssVtt 

 inch ; diameter of the annular colony ? ^ inch or less. Movements rota- 

 tory. Habitat — Marsh-water, with Sphagnum. 



Pyxidium urceolatum, sp. nov. (Fig. 10). 



Body vasiform, less than twice as long as broad, widest centrally, con- 

 stricted anteriorly, the posterior extremity narrowed to form a short color- 

 less prolongation somewhat broader than the pedicel ; cuticular surface 

 smooth ; peristome border truncate ; ciliary disk but slightly exserted, 

 ciliary circles two, long and fine ; vestibulum large, extending to near 

 the centre of the body ; contractile vesicle in close proximity to the pos- 

 terior part ot the vestibule and apparently emptying into it ; pedicel ex- 

 tremely short ; the contracted zooid ovate, posteriorly invaginate. Length 

 of body 253 inch. Habitat — Pond-water; on rootlets of Lemna. 



Bhabdostyla invaginata, sp. nov. (Fig. 11). 



Body vasiform, often slightly gibbous, about one and one-halt times as 

 long as broad, widest centrally, tapering posteriorly to the pedicel, and 

 anteriorly to the slight constriction beneath the peristome ; surface 

 transversely striate ; peristome border not revolute ; ciliary disk promi- 

 nent, conical, ciliary circles two ; pedicel short, about two fifths as long 



