176 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



vol,. XXXII. 



SCISSILABRA DALLI, new species. 



Shell small, depressed, lenticular, with acutely angulated periphery, 

 having' 3i transparent, A'itreous whorls which are separated by well- 

 marked sutures. The nepionic portion consists of the first If turns 

 and is scarcely differentiated from the rest of the shell. The upper 

 surface is evenly and gently rounded from the summit to the periphery, 

 which is strongl}^ and sharply carinated. Under side openly imibili- 

 cated, much less convex than the upper. The umbilical edge is 

 marked by an acute carina from which the cohunellar wall in the last 

 whorl extends almost vertically to where it joins the preceding turn. 

 This carina and vertical umbilical wall are characteristic of the last 

 turn only; in all the others which are visible in the umbilicus it appears 



Fig. 11.— SCISSILABRA DALLI. tt, TOP VIEW; 6, SIDE VIEW; C, BASAL VIEW. 



evenly rounded. Aperture very large, decidedl}^ oblique; outer lip 

 very broadly and strongly notched, the blunt angle of the notch 

 coinciding with the periphery of the shell; the portion of the lip pos- 

 terior to the sinus and its basal part somewhat sinuous; columella 

 vertical and slightly concave; parietal wall covered by a thick callus 

 which renders the peritreme almost continuous. 



The type. Cat. No. 192712 U.S.N.M., was collected in the beach 

 drift, San Diego, California. It measures: Greater diameter, 2 mm.; 

 lesser diameter, 1.5 mm.; altitude about 0.75 mm. 



Another specimen, Cat. No. 127562, U.S.N.M., comes from San 

 Pedro, California. A third specimen, Cat. No. 192713, U.S.N.M., 

 was dredged in 12 fathoms, blue mud bottom, at Monterey Bay by 

 Mr. S. S. Berry, and an additional specimen from the same locality is 

 in Mr. Berry's collection. 



