PARTULINA DUBIA, OAHU. 113 



surface slightly shining, the later whorls densely striatel 

 spirally, striae waved, descending, embryonic whorls very 

 densely and distinctly engraved. Embryonic shell of 8^2 

 whorls, the first 2 whorls brown under a whitish layer; third 

 whorl marked with oblique, angulated white stripes on a 

 reddish-brown ground. Following (neanic) whorls mottled 

 and streaked with white on a reddish-brown ground, which 

 becomes paler on the last whorl, which is indistinctly streaked 

 and mottled with creamy or brownish white, and girdled with 

 a narrow dark band at the periphery. The whorls ara 

 strongly convex. Aperture slightly oblique, purplish-brown, 

 with light streaks within. Peristome a trifle expanding at 

 the base, narrowly bordered within with white, but not thick- 

 ened. Oolumella slightly convex, not plicate, the margin 

 spreading in a triangle, white. 



Length 17, diam. 10.5 mm. ; fully 6 whorls. 



Length 15.5, diam. 10.2 mm. ; 5^4 whorls. 



West Maui: Waiehu Gulch (D. Thaanum). Cotypes in 

 coll. Bishop Museum and A. N. S. P. Also in Mr. Thaanum 's 

 collection at Hilo. 



This very distinct species is evidently related 'to the East 

 Mauian P. grisea Newc., from which it differs by the thinner 

 shell of somewhat different contour, the more convex whorls, 

 different pattern of the last embryonic whorl, larger umbili- 

 cus, dark peripheral band, etc. The aperture, lip and colu- 

 mella are more like P. physa than like P. grisea. The spire 

 is less drawn out and not so narrow above. P. aptycha Pfr., 

 which has not been found by recent collectors, is obviously 

 distinct. 



51. P. DUBIA (Newcomb). PI. 26, figs. 7 to 12. 



" Shell dextral, conically elongate, thin, finely decussately 

 striated, light corneous with radiating zigzag lines and 

 blotches of a light color. Whorls 6 ; suture simple. Aperture 

 ovate; 'columella white and bulimoid except in strongly de- 

 veloped adults where it is callous and obtusely dentatecL 

 Umbilicus small but pervious. Lip thickened. Slightly re- 

 flected. Length 0.8, breadth 0.55 inch " (Newc.). 



