AMASTRA, MOLOKAI. 267 



brown figures, on the last half-whorl becoming chestnut with 

 darker streaks ; this cuticle wanting in front of the aperture, 

 more or less deciduous elsewhere, and frequently almost 

 wholly lost in adult shells. The flat whorls of the conic em- 

 bryonic shell are costate and the second one shows a keel 

 close above the suture. Subsequent whorls have rather fine, 

 irregular growth-lines, and the last whorl sometimes shows 

 some obliquely-descending facets or malleation. The aperture 

 is nearly white within, and the lip a little thickened towards 

 and at the base. Columellar lamella rather small and ob- 

 lique. 



Length 17.3, diam. 10, aperture 9 mm. ; 6y 3 whorls. 



Length 17, diam. 9.8, aperture 8.5 mm. ; 6% whorls. 



Length 19, diam. 10.5, aperture 9 mm. ; 6% whorls. 



Molokai (Gulick, Meyer). Cotypes 104688, 57714, A. N. 

 S. P., 13446, Boston Soc. 



Amastra mucronata Newc., BORCHERDING, Zoologica, xix, 

 Heft 48, 1906, p. 119, pi. 10, f. 17 (Kalae). Not of New- 

 comb. Amastra mastersi Newc., BORCHERDING, t. c., p. 116, 

 pi. 10, figs. 16, 18. Not of Newcomb. 



The shell is more capacious than A. mucronata or A. simi- 

 laris, with a larger aperture. The precise locality of the 

 types is unknown, but Borcherding has figured the same form 

 from Kalae (copied in pi. 40, figs. 5, 6) and from Kawela 

 (pi. 40, figs. 2-4), under the names A. mucronata and A. mas- 

 tersi. He states that the long series examined indicates a 

 transition between the two forms, " the ornamental marking 

 of typical mucronata disappearing gradually and passing into 

 a more uniform epidermis." 



Three examples in the Cooke collection, pi. 37, figs. 10, 11, 

 12, have the zigzag pattern of the cuticle more confused, in 

 one example, fig. 10, it is almost wanting. These shells are 

 probably the same as what Borcherding has figured as A. 

 mastersi. 



This species is very closely related to the west Mauian A. 

 assimilis. It is decidedly more remote from A. mastersi. In 

 Molokai it may also claim kinship with A. uniplicata. 



