AMASTBA, OAHU. 171 



within and the lip is strengthened by a narrow but distinct 

 white rib within the edge. The columellar lamella is strong 

 and subhorizontal, and there is an extremely narrow umbilical 

 slit in all of the specimens (4) of the type lot. Consequent 

 upon the angularity of the base, around the axis, the junc- 

 tion of columellar and basal lips is somewhat spout-like. 



The other three shells are immature, wanting the lip-rib. 

 One is colored like the type, but the other two are of a slightly 

 transparent and dilute reddish-brown tint, the apical whorls 

 much darker in one example. All three show traces of a few 

 whitish or creamy spiral lines, at and above the periphery, 

 and all are covered with a thin cuticle. The periphery is 

 noticeably angular in front of the aperture in these immature 

 shells, but hardly perceptibly so in the adult type specimen. 

 The shortest shell measures, length 11.5, diam. 8.3 mm. 



The following form from the Main Range of Oahu ap- 

 proaches pellucida so closely that I hardly see the way clear 

 to separate the two forms as species, though I must admit the 

 possibility of convergent evolution in this case. 



160. A. BREVIATA Baldwin. PI. 30, figs. 15, 17, 18. 



Shell a little more solid, reddish-chestnut, pale below the 

 suture, behind the lip and around the perforation, and often 

 encircled with interrupted creamy lines and bands, at and 

 above the periphery. Aperture flesh-colored within ; lip very 

 little thickened; otherwise as in A. pellucida'. Length 12.3, 

 diam. 8 mm., whorls 5%. 



Oahu: Palolo and Halawa, a variety in Waimano. 



Amustra breviata BALDWIN, Proc. A. N. S. Phila., 1895, p. 

 231, pi. 11, f. 41, 42. Achatinella breviana BALDWIN, Cata- 

 logue, 1893, p. 8, name only. 



The type specimen is figured, figs. 17, 18. In some others 

 of the type lot there are no hydrophanous markings. It is 

 hardly distinguishable from A. pellucida, although Mr. Bald- 

 win states that the animals differ. Some difference in pigmen- 

 tation of the soft parts may reasonably be expected in -view 

 of the variation in color of the shells. In stating that this 

 species and A. pellucida are without epidermis, Mr. Baldwin 



