Bartsch — New Marine Mollusks from America. 37 



upon the seventh, and twenty-four upon the last turn. Intercostal spaces 

 about two thirds as wide as the ribs. In addition to the axial ribs there 

 are three strong spiral cords, of which the first is about as far anterior to 

 the summit of the whorls as it is distant from its median neighbor. The 

 first of these spiral cords is a little less strongly developed on the earlier 

 whorls than on the succeeding turns, where it almost equals the other two. 

 Tlie junction of the axial ril)s and the spiral cords forms strong tubercles, 

 of which those on the cord at the summit are well rounded, while those on 

 the median cord are truncated posteriorly and slope gently anteriorly. The 

 same is true of the supra-sutural cord. On the last whorl, however, the 

 tubercles are more elongated and the truncation at the anterior margin is 

 less pronounced, the long axis of the tubercles coinciding with the axis of the 

 shell. The spaces enclosed between the axial ribs and spiral cords are well 

 rounded pits. The summit of the whorls falls a little anterior to the peri- 

 pheral cord, and lets this appear as a narrow, smooth, sinuous thread in the 

 somewhat constricted suture. Periphery of the last whorl marked by a 

 strong cord, which constitutes the termination of the axial ribs. Base short 

 and rounded, but concave at the junction with the columella. The junc- 

 tion of the columella and the base is marked by a slender spiral cord. Aper- 

 ture broadly oval, decidedly channeled anteriorly; posterior angle obtuse; 

 outer lip thin, rendered sinuous by the external sculpture, which is also seen 

 within the aperture by transmitted light; inner lip reflected over and ap- 

 pressed to the columella. 



The type and two specimens of this species, Cat. No. 268,746, U. S. N. M., 

 were collected by Mr. George Willett at Forrester Island, Alaska. The type 

 has nine postnuclear whorls and measures: length, 7.5 mm.; diameter, 2.5 

 mm. Four additional specimens from the same station are in Mr. Willett's 

 collection. Another specimen. Cat. No. 340,936, U. S. N. M., was collected 

 by Mrs. Oldroyd at San Juan Islands. 



This species suggests Cerithiopsis (Cerifhiopsina) signa, but has much 

 larger nuclear whorls and is in every way more robust than that species. 



Alvania sanjuanensis, new species. 



Shell moderately large, chestnut brown excepting the tip which is a little 

 paler and the extreme base which is also lighter. Nuclear whorls one and 

 a half, well rounded (the sculpture of the nuclear whorls erroded in all the 

 shells seen except in a very small fraction of the last turn in the type, which 

 presents a finely, somewhat wavy, spirally lirate surface. I am not quite 

 certain whether axial threads are present or not). Nuclear whorls strongly 

 shouldered at the summit, strongly rounded, marked on the first turn by 

 three strong spiral cords, which occupy the anterior half of the turn ; on the 

 second turn a fourth cord occurs a little anterior to the median line between 

 the summit and the first strong cord, while on the next turn a fifth slender 

 thread makes its appearance between the summit and this cord. This last 

 cord at the summit never attains a strength as great as the third anterior 

 to it, while the second one is fully as strong on the penultimate turn. In 

 addition to these spiral cords the shell is marked by rather weak axial ribs, 



