dall: groups of bulimulus 



119 



than the preceding group, the surface spirally more or less sharplv 

 striate, often forming a fine granulation with the incremental lines. 

 There is a tendency to banding in the coloration. The axis is solid and 

 twisted behind, the later part tubular and larger. The aperture is 

 unarmed. Only approximatus lacks the spiral striation, if the single 

 specimen available is normal. 



Group of N. usUdatns (Nuciscus n.). 



N. iistulatus Sowerby, with five varieties. 



N . calvus Sowerby, with one variety. 



N. elaeodes Dall. I 



N. haemerodes Dall. I 



N. pallidus Reibisch. ' 



N. cinerarius Dall (+ cinereus Reibisch). 



A'', rugaiinus Dall (+ acutus Reibisch). 



N. jacohi Sowerby. 



N. tanner i Dall. 



N. perms Dall. 



This group is near the presumed original ancestor and is most widely 

 distributed among the islands, being particularly numerous on the largest 

 island, Albemarle. The shells are small, robust, rather stout and short, 

 with fine spiral striations to which in dusty situs is added strong cor- 

 rugation of the surface. There is a tendency to a pale band at the per- 

 iphery and the species var}- from whitish to brown. They are mostly 

 ground lovers but ascend the bushes to some extent during the season 

 of rains. The aperture is unarmed, the axis wholly tubular and hardly 

 twisted. 



Group of A^. hoodensis Dall. 



This is represented on the islands, as far as known, by a single species 

 which resembles the continental type more than the other island forms. 

 It is rather brightly banded and the adult has a thickened and reflected 

 peritreme, a feature unique among the island species. 



Group of N. unijasciatus (Reclasta n.). 



A^. unifasciaiiis Sowerby (not Reibisch). 

 A^. olla Dall, with one variety. 



By their thin and capacious shells these are readily separable from 

 the other groups. They tend to brownish or dingy olive color with 

 pale peripheral band. They are well distributed among the islands 

 and in the active state appear to frequent shrubbery. They are finely 

 axially wrinkled, polished and obscurely spirally striated with an occa- 

 sional elevated line of granules which in the 3^oung bear short hairs 

 which soon drop off. The aperture is unarmed and the axis as in the 

 section Nuciscus. 



Group of A^ escharifertis (Adenodia n.). 



A^. eschariferus Sowerby, and one variety, pileatus. 

 N. ventrosus Reibisch. 

 A^. subconoidalis Ancey. 

 A-", perspectivus Pfeiffer. 





