THE NAUTILUS. 137 



Aperture very large, subcircu'ar, posterior angle obtuse ; outer lip 

 thin ; columella curved, somewhat expanded and thickened basally ; 

 parietal wall covered with a thin callus. Operculum thin, horny. 



Twelve specimens of tliis species were collected by Dr. Fred. 

 Baker at Port Graham, Alaska, four of which are in the U. S. 

 National Museum, cat. no. 208433. One of these, the type, meas- 

 ures ; greater diameter 0.85 mm., lesser diameter 0.7 mm., altitude 

 0.4 mm. The remaining eight specimens are in Dr. Baker's collec- 

 tion. 



Alvania bakkri, new species. PI. XI, fig. 8. 



Shell minute, bluish white. Nuclear whorls one and one-third, 

 forming a moderately elevated spire. Upper half of the well-rounded 

 nuclear whorls marked by about ten very fine closely spaced spiral 

 striations, lower half marked by numerous closely spaced depressed 

 elongate granules, each of which has the long axis decidedly protrac- 

 tively slanted ; which lends to this part of the turn a finely blistered 

 appearance. Post-nuclear whorls u little more than two, well 

 rounded, separated by a strongly constricted suture marked by three 

 strong rounded spiral keels of which the strongest is a little anterior 

 to the posterior third between the sutures, while the anterior of the 

 other two, which are of equal strength, is at the periphery and the 

 third halfway between them. In addition to these keels the wiiorls 

 are marked by fine incised spiral lines between the keels which are 

 best developed on the well-rounded shoulder between the summit of 

 the whorls and the strong keel below it. Base of the last whorl 

 slightly protracted, well rounded, marked by two broad depressed 

 spiral cords of which tlie basal one which is a little anterior to the 

 middle is the broader. In addition to these are numerous exceed- 

 ingly fine spiral striations. The axial sculpture of the entire spire 

 and base consists of very fine incremental lines only. Aperture very 

 broadly ovate, almost circular, peritreme continuous, outer lip thick 

 within, beveled at the margin to form a sharp edge which is rend- 

 ered slightly sinuous by the external spiral sculpture ; columella 

 strong and strongly curved, parietal wall of the aperture appressed 

 to the preceding whorl. 



The type, cat. no. 208445 U. S. N. M., was collected by Dr. 

 Fred Baker at Port Graham, Alaska. It measures ; length 1.4 mm., 

 diameter 1.2 mm. 



