NO. 1863. M0LLU8KS OF THE 0ENU8 ALVANIA—BARTSCH. 357 



parietal wall covered with a thick callus which renders the peristome 

 complete. 



The type (Cat. No. 127373, U.S.N.M.) was dredged by the United 

 States Bureau of Fisheries steamer Albatross off Clarion Island, 

 Mexico, in one of the five hauls — 2991 to 2995, the depths of which 

 ranged from 31 to 460 fathoms. It has 4| post-nuclear whorls and 

 measures: Length 2.9 mm., diameter 1.3 mm. 



ALVANIA LARA, new species. 

 Plate 32, fig. 6. 



Shell elongate-ovate, white. Nuclear whorls decollated, excepting 

 the last quarter turn, which is smooth. Post-nuclear whorls shoul- 

 dered at the summit, marked by lamellar spiral keels, of which three 

 occur between the sutures on the first turn. Of these, the suprasu- 

 tural one is decidedly the strongest and gives a very strongly pro- 

 nounced angle to the whorls. The keel immediately below the summit 

 is next in strength, while the one between them — which is nearer the 

 suprasutural one than the one at the summit — is but feebly expressed. 

 On the second whorl an additional spiral cord makes its appearance 

 at the summit, while the two anterior to it gain considerably in 

 strength and become equal; the suprasutural one remains strong and 

 an additional slender cord makes its appearance halfway between the 

 strong suprasutural cord and the suture. On the penultimate whorl 

 the cord at the summit has increased in size to equal the cord adjacent 

 to it, and a slender thread appears in the space which separated the 

 second cord from the third on the preceding turn. The strong cord 

 on the preceding turn becomes considerabl}^ enfeebled and the space 

 between this and the suture is crossed by two rounded, slender, spiral 

 cords. In addition to the spiral sculpture, which exceeds the axial 

 sculpture in strength, the whorls are marked by rather strong, almost 

 vertical, axial ribs, of which 14 occur upon the first and second, and 

 16 upon the penultimate turn. The intersections of the spiral cords 

 and axial ribs form compressed tubercles, having their long axes 

 parallel to the spiral sculpture. Suture strongly channeled. Periph- 

 ery of the last whorl decidedly channeled, the posterior edge of the 

 base being suddenly truncated at the channeled suture, which makes 

 the peripheral sulcus appear as a triangular notch in profile. Base 

 moderately long, attenuated anteriorly, marked by eight spiral cords, 

 the posterior of which is the strongest and is followed by three very 

 slender threads which in turn are succeeded by two strong and two 

 low feeble cords. Aperture oblique, oval; posterior angle obtuse; 

 outer lip thin at the edge, reenforced immediately behind the edge 

 by a strong varix; inner lip oblique, stout, curved and somewhat 

 reflected over, and appressed to the base; parietal wall covered l^y a 

 moderately thick callus. 



