88 ACLIS. 



A. GLABRA, Sars. PL 18, figs. 72, 73. 



Shining, vitreous, white, smooth ; whorls 9, convex, narrower 

 and not so rapidly increasing as the preceding species. 

 Length, 5 '5 mill. 



Norway 



A. EXIGUA, Sars. PI. 17, fig. 57. 



Whitish, subopaque, glabrous, whorls 8, slightly convex, the last 

 a little dilated at the aperture, umbilicus distinctly rimate. 

 Length, 2 mill. 



Arctic Norway. 



A. ATTENUANS, Jeffreys. PI. 17, fig. 40. 



Thin, white, smooth, transparent, glossy; whorls 6-7, convex, 

 suture well-defined, but not deep. Length 1'25 mill. 



Mediterranean. 



The aperture is a little more contracted below than in the last 

 species and the columella more perpendicular ; perhaps not adult. 

 A. SARISSA, Watson. PL 17, fig. 54. 



Smooth, white, glossy, umbilicus a mere chink ; whorls 9 ; well 

 rounded ; with a few slight growth lines. Length, 3'75 mill. 



Off Pernambueo, 350 fms. 



Broader, with fewer, rounder whorls than in A. Walleri. 



A. MINUTISSIMA, Watson. PL 17, fig. 55. 



Smooth, pale brownish hyaline ; whorls 7, slightly convex, 

 aperture a little narrowly produced below. Length '25 mill. 



Off Raine Isl., N. E. Australia, 155 fms. 



Probably the smallest known gastropod, being the one-hundredth 

 of an inch in length. 



Section GR APHIS, Jeffreys, 1867. 



A. UNICA, Montagu. PL 18, fig. 66. 



Thin, white, semitransparent, somewhat glossy, with numerous 

 flexuous, longitudinal ribs, reticulated by many fine spiral ridges or 

 striae ; whorls 9-10. moderately convex, very slowly increasing, with 

 deep suture. Length, 3 mill. 



Europe. 

 A. GRACILIS, Jeffreys. PL 18, fig. 67. 



Thick, semitransparent, glossy, yellowish white; whorls 5, 

 convex, very slowly increasing, a little round shouldered, with about 



