MUSEUM OF COMPAKATIVE ZOOLOGY. 83 



Triforis hircus n. s. 



Shell elongated, acutely tapered, with fourteen or more rather inflated 

 whorls of translucent whitish color ; transverse sculpture of some twenty-one 

 slightly oblique rounded ribleta with somewhat narrower interspaces, which 

 are prominent on the periphery of the whorls, and evanescent toward the 

 sutures ; these riblets are nearly parallel with the axis in the younger shells, 

 and become more oblique in the adults ; each bears two nodules caused by the 

 intersection of the spiral sculpture ; beside these there are faint lines of growth, 

 most distinct on the polished and flattened base; spiral sculpture consisting 

 of a thread behind the suture, undulated by the ends of the transverse riMets 

 in the young, simple and regular in the more mature whorls, and forming on 

 the last whorl the margin of the base, and two flattened threads, separated by a 

 wider groove, which rise to nodules where they intersect the transverse sculp- 

 ture ; the distance from the suture forward to the posterior spiral thread is 

 greater than from the anterior thread forward to the next suture, and this 

 wider space has a somewhat excavated appearance, the posterior edge of the 

 whorl being appressed to the suture, and slightly thickened where it meets the 

 post-sutural spiral rib ; base flattened, yellowish, polished, with a single faint 

 thread near the periphery ; aperture squarish, not completely developed in the 

 specimens accessible ; canal very short ; pillar twisted, short, stout, of a darker 

 yellow than the rest ; apex decollated, probably rather pointed. Lon. of shell 

 12.5. Max. lat. 3.0. Lon. of last whorl, 3.0 ; of aperture, 1.9. Lat. of aperture, 

 1.75; lat. of first remaining whorl, 0.87 mm. 



Yucatan Strait, 640 fms. 



This is closest to T. bigemma, from which it differs in the less pronounced 

 sculpture, the absence of the first ante-sutural nodulated spiral rib, and the 

 more acute taper of the shell. A large series might show them to be vari- 

 eties of one species, but in the absence of connecting links they can hardly be 

 properly united. 



Triforis cylindrellus n. s. 



Shell small, slender, sinistral, whitish, of twelve or fourteen whorls, tapered in 

 the adult both ways, the spire rather acutely (the nucleus is missing), and the 

 last whorl being a little more slender than the two immediately preceding it ; 

 transverse sculpture of twenty or more close, faint plications, extending from 

 suture to suture, a little less Btrong anteriorly, and in the Lasl whorl evanes- 

 cent in advance of the periphery ; the spiral sculpture consisting of L-ehaped 

 grooves, one side of which is nearly vertical to the axis of the shell and the 

 other slopes spireward ; of these there are three, nearly equidistant, the ante- 

 rior one, being separated from the suture in front of it by a smooth space, 

 to that space the effect of a post-sutural rib; base prominent, inflated, with 

 one faint groove near the periphery, the whole ahell showing more or less evi- 

 dent lines of growth, and occasionally faint revolving stria- ; whorls inflated, 

 distinct; suture appressed, conspicuous; column twisted, moderately long, 



