NO. 1574. WEST AMERICAN PYRAArlDELLID.E—DALL AND BARTSCH. 517 



the keels. Postnuclear whorls well rounded, slopinglj shouldered 

 at the summit and .>#parated by constricted sutures, ornamented by 

 almost equal and equally spaced spiral keels and axial ribs between 

 the sutures on the spire. There are 4 spiral keels on the first, sec- 

 ond, and third whorls, on the fourth, and 7 upon the penultimate 

 whorl. The first of these keels is on the shoulder of the whorl near 

 the summit and is somewhat less developed than the rest. The axial 

 ribs are best developed on the early Avhorls, where the}" extend 

 equally strong- from the sunmiit to the periphery; on the antepemd- 

 timate and penultimate turns they ))ecome somewhat enfeebled from 

 the middle of the whorl between the sutures to the periphery. 

 There are about ir» of these ribs on the first, 18 on the third, 20 

 upon the fourth, and 22 upon the penultimate turn. The intersec- 

 tions of the ribs and spiral keels form low elongated tubercles, the 

 long axis of which coincides with the spiral sculptiu'c. The meshes 

 inclosed by the keels and ribs are deeply impressed squarish pits. 

 Periphery and base of the last whorl well rounded, the latter some- 

 what inflated and marked by t) spiral cords which aie successively 

 closer spaced and a little less stiongly developed from the peripher\" 

 to the umbilical area. The chaimels between the cords are crossed 

 by many very slender raised vertical threads. Aperture oval, slightly 

 effuse anteriorly; outer lip thin; columella leen forced on its poste- 

 rior two-thirds by the attenuated base, free and somewhat revolute 

 anteriorily; parietal wall glazed by a thui callus. 



The type has (> postnuclear whorls and measures: Length 3.3 mm., 

 diameter 1.2 mm. It and 9 additional specimens are Cat. No. 10Tr)9(i, 

 U.S.N.M., and were collected by Dr. C. F. Newcombe at Cumshewa 

 Inlet, Queen Charlotte Island, Biitish Columbia, in 10 fathoms. Two 

 other lots of one specimen each come fiom Monterey, Cat. No. 73998, 

 U.S.N.M., in the Stearns collection, and Cat. No. 1902S3, T.S.N.M., 

 collected by Mr. F. L. P.utton. 



Subgenus IVIDIA Dall and Bartsch. 



hyidia D.^ii-and Bakt,s(h, I'ror Biol. Soc, Washintrtun, 1904, XVII, p. 11. 



Shell sculptured with hinudlose axial ribs and spiral keels, their 

 intersections not nodulose. 



Type. — Parilumht (trnxiid C'arpentcr. 



ODOSTOMIA (IVIDIA) NAVISA, new species. 

 Platf XI. VI, Hjis. L', L'<f. 



Shell of medium size, strongly sculptured, subdiaphanous to milk- 

 white. Nuclear whorls at least 2, obliquely a little more than half 

 immersed, Postnuclear whorls strongly shouldered, subtabulated, 

 with a strong broad spiral keel limiting the anterior edge of the shoul- 



