342 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.41. 



last whorl falls anterior to the peripheral cord on the penultimate 

 whorl, displaying the peripheral cord completely in the suture. The 

 spaces inclosed between the spiral cords and the axial ribs are elon- 

 gated, oval pits about as wide as the spiral cords. Suture strongly 

 and deeply channeled. Periphery of the last whorl marked by a 

 spiral cord, which is separated from the first supraperipheral cord by 

 a channel as wide as that separating the supraperipheral cord from 

 its posterior neighbor. The axial ribs terminate at the posterior edge 

 of the peripheral cord. Base moderately long, slightly produced 

 anteriorly, almost flattened, marked by 8 equal and equaUy spaced, 

 spiral cords, which are a little broader than the channels that separate 

 them. Aperture oval; posterior angle obtuse; outer lip thick within, 

 thin at edge; inner lip strong, curved, reflected over and appressed 

 to the base; parietal wall covered with a thick caUus, which renders 

 the peritreme complete. 



The type and another specimen (Cat. No. 213685, U.S.N.M.) are 

 fossils and come from sand rock, San Pedro, California. The type 

 has 3 1^ post-nuclear whorls and measures: Length, 2.2 mm., diameter 

 1.2 mm. 



ALVANIA FILOSA Carpenter. 



Plate 30, fig. 7. 



Alvania jilosa Carpenter, Ann. Mag. Nat. Hist., ser. 3, vol. 15, 1865, p. 28. 



Shell elongate-conic, thin, translucent, yellowish white. Nuclear 

 whorls one and one-half, well rounded, smooth. Post-nuclear whorls 

 well rounded, roundly shouldered at the summit, marked by slender, 

 feebly developed, sinuous, axial riblets. In addition to these riblets, 

 the whorls are marked by equal and equally spaced, spiral cords which 

 are equal to the riblets in strength. Of these cords, 10 occur be- 

 tween the sutures on the antepenultimate, and 12 on the penultimate 

 turn. The spaces inclosed between the sj^iral cords and the axial 

 ribs are shaUow, impressed, squarish pits. Suture strongly con- 

 stricted. Periphery and the rather short base of the last whorl well 

 rounded; the latter very narrowly umbilicated, marked by eight equal 

 and equally spaced, spiral cords, which are a little wider than tlie 

 spaces that separate them. The sulci between the spiral cords on the 

 base are crossed by the feeble extensions of the axial riblets. Aper- 

 ture broadly oval; posterior angle obtuse; outer lip thm, showing 

 the external sculpture withm; inner lip moderately stout, curved and 

 reflected, the posterior half appressed to the base; parietal wall cov- 

 ered with a thick callus, rendering the peritreme complete. 



Doctor Carpenter's type (Cat. No. 36632, U.S.N.M.) was collected 

 by J. G. Swan at Neah Bay, Washington. It has 4 post-nuclear 

 whorls and measures: Length 3.5 mm., diameter 1.7 mm. This shell 

 suffered an injury shortly after passing the nepionic stage and it is 

 quite possible that the multifilations which characterize this form 



