336 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.41. 



Sutures not channeled. 

 Shell elongate-conic. 



Sphal cords between the sutures, 5 effusa, p. 358. 



Spiral cords between the sutures, 3 sequisculpta, p. 358. 



Shell not elongate-conic. 

 Shell broadly ovate. 



Basal cords, 2 almo, p. 359. 



Basal cords, 4 oldroydse, p. 360. 



Shell subglobose tumida, p. 361. 



ALVANIA CASTANELLA Dall. • 



Plate 29, fig. 1. 

 Alvania cast inella Dall, Proc. U. S. Nat. Mus., vol. 9, 1886, p. 307, pi. 3, fig. 5. 



Shell elongate-ovate, thin, yello Tish-white. Nuclear whorls about 

 one and three-quarters, well rounded, smooth. Post-nuclear whorls 

 strongly, slopingly shouldered at the summit, well rounded, marked 

 between the sutures by six spiral keels, the first of wliich adjoins the 

 strongly channeled suture, while the second marks the angle of the 

 shoulder; the remaining four growing gradually and successively 

 weaker and a little closer spaced. In addition to the spiral sculpture, 

 the whorls are marked by numerous very fine, incremental lines. 

 Suture quite strongly constricted. Periphery of the last whorl well 

 rounded. Base moderately long, well rounded, very narrowly umbiH- 

 cated, marked by six equal and equally spaced, spiral keels. Aper- 

 ture semicircular; posterior angle obtuse; outer hp tliin, showing 

 the external sculpture witliin; inner Hp tliin, strongly curved and 

 slightly revolute; parietal wall covered with a m^oderately thick 

 callus, wliich renders the peritreme complete; operculum thin, horny. 



The type (Cat. No. 213677, U.S.N.M.) and another specimen were 

 collected by Doctor Dall at Atka Island, Alaska. The type has four 

 post-nuclear whorls and measures: Length 2.4 mm., diameter 1.3 mm. 

 Cat. No. 213678, U.S.N.M., contains 9 specimens taken from sponges 

 on the beach, at low water, at Kyska Harbor, Aleutian Islands, Alaska. 



ALVANIA AURIVILLII Dall. 

 Plate 29, fig. 5. 

 Alvania aurivillii Dall, Proc. U. S. Nat. Mus., vol. 9, 1886, p. 308, pi. 4, fig. 8. 

 Shell elongate-conic, tliin, light yellow. Nuclear whorls one and 

 one-half, strongly rounded, smooth. Post-nuclear whorls rounded, 

 shouldered at the summit, marked by two strong, spiral keels, be- 

 tw^een the sutures, on the first two turns ; the first keel being on the 

 middle and the second a little posterior to the suture; the space be- 

 tween the summit and the first keel slopes regularly. Beginning with 

 the third whorl a third keel appears, and the space between the 

 sutures is here divided into four parts, of which the one at the summit 

 is a little broader than the rest. On tlio last turn the peripheral keel 



