1885.] ** rstokes. 



prolonged anteriorly as a short, projecting crescentic lip ; peristome-field 

 extending for about one-third the entire length of the body, the right-hand 

 bolder ciliate and apparently having a narrow band-like undulating mem- 

 brane ; ventral seta? in two median lines continued to the termination of 

 the caudal prolongation, those of the right-hand series largest and most 

 numerous ; marginal seta? large, projecting beyond the body-margin ante- 

 riorly on the right-hand side, and about the caudal extremity where they 

 are longest and most abundantly developed, those of the right-hand body 

 margin largest and conspicuously flattened ; frontal styles three ; contrac- 

 tile vesicle single, spherical, near the center of the left-hand border ; 

 nucleus double, ovate ; dorsal aspect bearing a median and an uninter- 

 rupted marginal series of immotile hispid setae ; anal aperture opening on 

 the dorsal surface near the beginning of the caudal prolongation. Length 

 of body, 1-180 to 1-150 inch. Habitat. — Fresh water. 



Another member of the preceding genus, whose habitat is the Sphagnum 

 swamp, is so distinctive in form that the diagnosis and figure (Fig. 10) are 

 alone needed for its recognition. It is one of the most active of all the 

 usually frisky members of the genus, darting out of the field, frequently 

 swimming backward at the moment, so as to make its study rather diffi- 

 cult. It is very flexible and elastic, and at the same time one of the 

 brightest, most graceful and beautiful of the handsome group. The 

 extended body is delineated, in Fig. 10, as well as the absence of color, 

 life and motion permit. 



Uroleptuslongicaudatus, sp. nov. Body narrowly sub-fusiform, elongate, 

 about eight times as long as broad, extensile, widest centrally, tapering 

 posteriorly to a long, narrow, attenuate tail-like prolongation forming one- 

 third the length of the entire body ; anteriorly constricted into a neck- 

 like portion, the frontal region expanded and rounded ; lip narrowly cres- 

 centic ; frontal styles three ; marginal setae large, flattened, projecting, long 

 est and most abundantly developed about the caudal prolongation and 

 posterior extremity ; ventral setae in two closely approximated median 

 rows, one only continued through the caudal prolongation ; peristome- 

 field confined to the anterior fifth of the lower surface, the right-hand 

 border bearing a narrow membrane ; contractile vesicle single, spherical, 

 near the left-hand border of the neck-like constriction ; nucleus double, 

 ovate ; anal aperture dorsal, near the beginning of the tail-like prolonga- 

 tion ; hispid dorsal setae forming several longitudinal rows. Length of 

 extended body, 1-120 inch. Habitat. — Marsh water, with Sphagnum. 



Among the Hypotrichous Infusoria canal-like contractile vesicles are 

 comparatively rare, but a spherical pulsating vacuole with canal-like diver- 

 ticula, somewhat resembling that of Stentor, has been observed only in the 

 animalcule here referred to under the name of Eschaneustyla brachytona. 

 In Spirostomum the canal-like contractile vesicle possesses an enlargement 

 at its posterior termination ; in Stentor the single spherical vacuole gives off 

 one branch which encircles the peristome-field, and another that extends 

 along one lateral border, thus presenting a likeness to what obtains in this 



