V0 1889."'] PROCEEDINGS OF THE NATIONAL MUSEUM. 305 



less eroded iu all the specimens, though living when taken ; whorls 

 slightly rounded, not inflated; sculpture chiefly of fine, subequal, flat- 

 tened, narrow, slightly flexuous transverse plaits, which on the earlier 

 whorls reach forward to the suture, but on the later ones become obso- 

 lete near the periphery, and tend to disappear altogether near the aper- 

 ture on the last whorl of the adult shell; these plaits are separated by 

 narrower, rather deep grooves, and end at the suture behind rather 

 blui-tly, though they can hardly be said to coronate it; there are thirty- 

 five or forty of the plaits on the penultimate whorl; suture very dis- 

 tinct, slightly channeled, but not deep; there is no anal fasciole; the 

 aperture is shaped like a melon seed, the outer lip evenly arched, pro- 

 jecting somewhat in front of the periphery, not thickened or reflected, 

 and with no constriction for a canal; body and pillar without callus; 

 the columella straight, very slender, not recurved; siphonal notch ex- 

 tremely shallow, hardly differentiated from the aperture; interior of 

 the aperture polished, smooth, dark brown, the pillar livid white or 

 flesh color; siphonal fasciole, none; lines of growth not prominent, 

 the surface showing obscure faint spiral stria? or scratches, but no spiral 

 sculpture. Maximum longitude of shell, 48; maximum latitude, 19 mm . 



Hab. — Station 2793, oft" the coast of Ecuador, in 741 fathoms, mud, 

 and Station 2807, near the Galapagos Islands, iu the Pacific, in 812 

 fathoms, coral mud ; temperatures in both cases 3S°.4 F. 



The first mentioned specimen was collected with Leucosyrinx persim- 

 His and Pleurotomella cingulata. 



There is between the internal aragonitic layer and the epidermis a 

 rather thick layer of a cretaceous nature easily eroded, and the. action 

 of solvents upon this even in living specimens is extremely marked. 

 The operculum is thin, yellowish brown, with strong growth lines and 

 a large surface of attachment. It reaches a length of 10 mm and a 

 breadth of G mm . It is shaped like that of Fusus, but more curved, and 

 varies somewhat iu form in different specimens. The nucleus is apical. 



The soft parts are mostly yellowish white. There is a purpuriferous 

 gland alongside the distal part of the intestine which ejects a dark 

 rose-colored dye. The head is wide, the tentacles broad, flattened, and 

 counate at the median sinus. The gills, ospbradium, and siphon are as 

 usual. The foot is wide, rouuded-acute behind, double-edged and 

 slightly auriculate in front. The proboscis is small and short, with large 

 salivary glands whose axis carries a greenish streak. There is no poi- 

 son gland or dental sac. The auimal appears to be edentulous. The 

 verge is large, stout, a little flattened, with its tip obliquely truncate, 

 leaving a granulous oval area at the upper extreme of which is a small 

 conical papilla. The anal orifice is not prominent. The surface exudes 

 an abundant sticky mucus. 



This very beautiful and remarkable shell is Pleurotomoid in its char- 

 acters, though it wants the anal notch and fasciole. Although the oper- 

 culum is arcuate it is not coiled upon itself. The figure, though accu- 

 Proc. N. M. 89 20 



