290 bulletin: museum of compakative zoology. 



tbree-xvliorled, -white, polished, -n-itli a peripheral carina on tlie third •whorl 

 which terminates abruptly ; subsequent whorls four and a half, strongly sculp- 

 tured ; suture distinct, simple; whorls with 12-14 strong axial, slightly pro- 

 tractive ribs, faint on the anal fasciole, strong at the shoulder, and gradually 

 attenuated over the base ; these are crossed by (ou the last whorl about fourteen) 

 strong, subequal, equidistant channelled sulci, absent on tlie fasciole, obsolete in 

 the depressions between the ribs, but cutting the summits of the ribs into squarish 

 nodules ; the fasciole is smooth and polished, but shows about four alternate 

 opaque and translucent spiral bands of white, which at first look like threads ; 

 aperture narrow, anal sulcus strong, not deep, surrounded with a heavy callus ; 

 outer lip callous, forming a heavy varix, with six or seven internal Urae strongest 

 and dentiform at the margin ; body with a heavy and prominent anal callus sepa- 

 rated by a gap from eight or nine dentiform lirae on the straight pillar ; canal 

 short, wide, at the anterior margin flaring. Lon. of shell, 10.4 ; of last whorl, 

 7-0; of aperture, 6.0; max. diam. 5.0 mm. 



U. S. S. " Albatross," station 3391, Gulf of Panama, in 153 fathoms, mud, 

 bottom temperature 55°.8 F. U. S. N. Mus. 123,115. 



I do not feel certain that the existing nuclear shell is not an internal cast of 

 a very thin, perhaps differently sculptured, larval shell, of which in one specimen 

 I fancy traces are visible near the suture. 



Qlyphostoma thalassoma Dall, n. sp. 



Shell slender, acute, eight- whorled, beside a nucleus of about a whorl and a half; 

 the spire longer than the aperture, whorls gently rounded, suture appressed, not 

 deep ; nsial sculpture of (on the penultimate whorl twenty-one) feeble, narrow, 

 protractive ribs, concavely arcuate where they pass over the anal fasciole, and at 

 the other end becoming obsolete on the base of the whorl, their interspaces 

 narrower or subequal to the ribs; these are crossed by (between the sutures five 

 or six, on the last whorl about eighteen) rounded, equal, strong spiral threads, with 

 narrower interspaces, and hardly enlarged where they intersect the ribs ; the anal 

 fasciole is rather obscure and sculptured with incremental lines, and on the ante- 

 rior edge about three very fine spiral threads; on the canal beyond the major 

 threads are about fifteen minor spirals closely crowded ; outer lip with a strong 

 varix and conspicuous rounded anal sulcus, behind which on the body is an arcu- 

 ate mass of callus; edge of the outer lip thin, strongly lirate within, the anterior 

 margin denticulate; inner lip thinly callous, with a marginal row of small pustules 

 opposite the lirae; canal conslrictcd, deeply sulcate, somewhat recurved; shell 

 discolored, probably originally whitish. Length of shell, 19.5; of last whorl, 12.0; 

 of aperture, 9.0; max. diam. 6.5 mm. 



U. S. S. " Albatross," station 3017, off Cape Lobos, Gulf of California, in 58 

 fathoms, mud, bottom tcniperat\ire 61°. 8 F. U. S. N. Mus. 110,612. 



It is pnsisible that, with greater age, tlie armature of the inner lip might be 

 more couspicuoua, as the shell may not be completely mature. 



