NATICA. 53 



Section AMAUROPSIS, Morch, 1851. 

 X. HELICOIDES, Johnson. PL 22, fig. 31. 



Thin, with channeled suture ; umbilicus a narrow line ; chalk} r 

 white, covered with a light yellowish brown epidermis. 

 Length, 1-1*5 inches. 



Newfoundland, Arctic Oeean, Norway, Siberia. 

 It is N. canaliculata, Gould, N.fragilis, Leach, N. cornea, 

 Moller, and perhaps N. Islandica, Gmelin. 



N. PURPUREA, Dall. PI. 22, fig. 32. 



Suture channeled, umbilicus a mere chink or closed, inner lip 

 with a thin callus ; whorls 4, inflated, with fine revolving grooves ; 

 purplish brown, under a yellowish epidermis. Length, 1 inch. 



Alaska. 



Differs from the preceding species in sculpture and color, and 

 is usually more globose. 



N. GLOBULUS, Angas. PL 22, fig. 33. 



Rimate, rather thin, shining; orange horn-color, much paler 

 on the last whorl towards the aperture ; two narrow concentric 

 raised keels on the subapical whorl ; nearly smooth, a few 

 microscopical spiral stride here and there crossing the growth- 

 lines ; columella slightly thickened and expanded over the um- 

 bilicus. Length, 5 mill. 



Holdfast Bay, So. Australia. 



The pertinence of this species to Amauropsis is very ques- 

 tionable. 



Subgenus AMAURELLA, A. Ad., 1867. 



The species, three in number, are unfigured : N. Japonica, 

 N. glabrata and N. semistriata, A. Ad. 



Japan. 



Unfigured and Undetermined Species. 



X. RUSSA (Arctic Ocean) and N. SEVERA (Japan), of Gould. 



N. PHILIPPINENSIS (Philippines), N. ATRYPA ( W. of Gape York, 

 S. W. of Papua), X. PSEUSTES (Fiji Islands), X. SUTURALIS 

 (Kerguelen IsL), X. RAD i AT A (Bermuda), X. AMPHIALA (E. N. 

 E.from N. Zealand), X. LEPTALEA ( West Indies). X. XANTHA 



