352 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 41. 



ALVANIA ACUTILIRATA Carpenter. 

 Plate 31, fig. 3. 

 Rissoa acutilirata Carpenter, Proc. Gala. Acad. Sci., vol. 3, 1866, p. 217. 



Shell small, ovate, yellowish white, with the base of the columella 

 and the posterior angle of the aperture purplish chestnut brown. 

 Nuclear whorls two and one-half, small, strongly rounded, smooth. 

 Post-nuclear whorls very feebly shouldered at the summit, marked 

 by regular, slender, slightly protractive, axial ribs, which are about 

 half as wide as the spaces that separate them. Of these ribs 24 

 occur upon the first, 22 upon the second, and 20 upon the penulti- 

 mate turn. In addition to the axial ribs, the whorls are marked by 

 slender spiral cords which are a little more than half as strong as 

 the axial ribs, and about half as wide as the spaces that separate 

 them. Of these cords, 6 occur between the sutures on the first, and 

 7 on the second and the penultimate turn. The spaces mclosed 

 between the axial ribs and the spiral cords are elongated pits, having 

 their long axes parallel to the spiral sculpture. Suture well impressed. 

 Periphery of the last whorl marked by a well-rounded, spiral cord, 

 at the posterior edge of which the axial ribs terminate. Base well 

 rounded, feebly produced anteriorly, marked by 8 spiral cords, which 

 grow successively weaker and more closely spaced from the periphery 

 to the umbilical region. Aperture broadly oval; posterior angle 

 acute; outer lip rather thin at the edge, thinner within, showing the 

 external sculpture within; inner lip moderately stout, strongly curved 

 and reflected over and appressed to the base; parietal wall covered 

 with a thick callus, rendering the peritreme complete. 



The specimen described and figured (Cat. No. 153072, U.S.N.M.) 

 comes from San Diego Ba}/", California. It has 3 post-nuclear whorls 

 and measures: Length 2.3 mm., diameter 1.2 mm. 



Specimens examined. 



Catalogue No. 



195335 



213693 



152195 



129005 



153072 (figured) 

 213694 



198958 



Locality. 



Monterey, California 



Saa Pedro, California 



Do 



San Diego, California 



San Diego Bay, California (drift) 



United States Bureau of Fisheries station 2932, Los Coronados Island 



California (20 fathoms, 58°, gray sand and broken shell bottom). 

 Todos Santos Bay, Lower California , 



Number 

 of speci- 

 mens. 



ALVANIA COSMIA, new species. 

 Plate 31, fig. 4. 



Shell small, elongate-ovate, white, semitranslucent. Nuclear 

 whorls one and one-half, marked by four, moderately strong, spiral 

 lirations which are separated by strongly impressed lines. Post- 



