NEW WEST COAST MOLLUSKS—BARTSCH. 



179 



spotted. In montereyensis the variegated forms predominate; that is, 

 the shells are whitish mottled with rust brown. The t^^pe, Cat. 

 No. 32221, U.S.N.M., has 10 whorls, and measures: Length 13.8 nun.; 

 diameter 5 mm. 



BITTIUM ESURIENS MULTIFILOSUM, new subspecies. 



Shell similar to B. esurUms, l)ut hti-ving 7 spiral keels l)etween the 

 sutures on the whorls of the spire instead of 4. 



The type, Cat. No. 127051, U.S.N.M., was collected by Mrs. Old- 

 royd at Whites Point, San Pedro, California. It has 10 whorls, and 

 measures: Length 9.2 mm.; diameter 3 mm. 



Specimens examined. 



BITTIUM TUMIDUM, new species. 



Shell of medium size, light yellowish-})rown, shining. Nuclear 

 whorls decollated. Post-nuclear whorls somewhat inflated, well 

 rounded, separated by constricted sutures and ornamented with strong 

 tuberculate axial ribs, of which there are 18 upon the second of the 

 remaining whorls and 22 upon the penultimate turn. In addition to 

 the axial ribs there are four unequally broad, low, spiral ridges 

 between the sutures, which are much wider than the spaces which 

 separate them, the latter appearing as strongly incised lines. The 

 intersection of these ridges and the ribs form the tubercles. The 

 whorls slope gently from the second spiral ridge toward the summit, 

 and the first row of tubercles which is only feebly developed is located 

 on the sloping shoulder. The second set of tubercles are rounded 

 while the third and fourth rows are decidedly elongated. Periphery 

 of the last turn marked by a strong smooth spiral keel, which is sepa- 

 rated from the supraperipheral keel by a mere constriction. Base 

 rather .short without keel, marked only by lines of growth. Aperture 

 suboval, decidedly channeled anteriorly; outer lip rendered sinuous 

 by the external sculpture; columella short, very broad, and slightly 

 expanded at the insertion, a little lighter in color than the rest of the 

 shell; provided with a strong callus on its inner edge which is reflected 

 over the parietal wall. 



The type, Cat. No. 74001, U.S.N.M., was collected by Canfield at 

 Monterey, California. It has 8 postnuclear whorls and measures: 



