stokes.] -^^O [Sept. 16, 



Bothrostoma undulans, sp. nov. Fig. 9. 



Body ovate, about two and one-half times as long as broad, colorless, 

 soft and changeable in shape, the anterior extremity obtusely pointed, the 

 posterior border truncate ; cuticular surface longitudinally striate ; peri- 

 stome-field extending obliquely inwards beyond the body-centre ; undu- 

 lating membrane large, often resembling a long anteriorly curved seta, 

 extending from the oral aperture to within one-third of the body-length of 

 the antei'ior extremity ; oral aperture at the posterior termination of the 

 peristome, ovate ; pharynx short, ciliate, infundibuliform ; posterior setose 

 cilia long and conspicuous ; nucleus ovate, situated in the anterior body- 

 half; contractile vesicle large, single, spherical, placed near the posterior 

 extremity. Length of body, ^\^ inch. Hah. — Standing pond water. 



Hymenostoma magna, sp. nov. Fig. 10. 



Body ovate, depressed, about twice as long as broad, the dorsal surface 

 convex, the ventral flattened and chiefly occupied by the wide, adoral 

 depression or groove which extends from the frontal border almost to the 

 posterior extremity, the latter slightly produced and truncate, a broad 

 tuft of larger cilia fringing the truncation ; anterior border narrow, 

 obliquely rounded ; left-hand margin of the peristome bearing a series of 

 long, fine cilia, directed across the adoral depression, the left-hand border 

 furnished with an undulating membrane, widest anteriorly and projecting 

 beyond the frontal body-margin as a sinistrally directed, concave acumi- 

 nation ; oral aperture near the posterior extremity of the peristome ; nu- 

 cleus ovate, slightly curved, located posteriorly on the right-hand side of 

 the body ; contractile vesicle double, one near the posterior extremity, 

 the other near the right-hand side of the body-centre, and formed, after 

 systole, by the coalescence of several small vacuoles ; cuticular surface 

 fine striate longitudinally. Length of body, 2I5 inch. Hab. — Standing 

 pond water. Movement a rapid often backward revolution on the longi- 

 tudinal axis. 



This, the second known member of the genus, is readily distinguishable 

 from H. hyinenopliora by the larger body, it being about twice as large as 

 the last mentioned species, hj the posterior truncation with its ciliary 

 fringe, and by the form of the peristomal membrane, with its anterior 

 projecting acumination. As in H. hymenophora the food masses collect in 

 the left-hand side of the body. 



Conjugation has been observed, union taking place between the ventral 

 surfaces of the right-hand body margins. 



Vorticella 2nmlla, sp. nov. Fig. IL 



Body conical- campanulate, less than twice as long as broad, widest an- 

 teriorly, tapering thence to the pedicle ; constricted immediately beneath 

 the peristome ; cuticular surface transversely striate ; peristome equaling 



