PARTULINA. 357 



No blends between the normal pattern and balteata were 

 noticed. 



In another colony, west of Meyer's lake, the markings are 

 bolder and there is no whitish belt. The oblique-striped pat- 

 tern is usually more dislocated than in pi. 54, figs. 1, la, but it 

 always gives place to a vertical striping on the latter part of 

 the last whorl. 



On the flat east of the peak of Puukolekole the majority of 

 specimens have the pattern of pi. 54, fig. 3, but about one- 

 third are cinnamon-buff with a dark peripheral band, bor- 

 dered below with a white band, pi. 54, fig. 2. This is very 

 much the color of the normal embryo shell, in the first half of 

 the third whorl. 



The several stages of the color-pattern are rather well- 

 marked in P. helena, and deserve further study. 



P. THWINGI P. & C., n. sp. PI. 54, figs. 6, 6a, 6b. 



The shell is dextral, perforate, ovate-conic, moderately solid. 

 White, profusely maculate and mottled with mummy brown, 

 under the lens showing a few ochraceous spots or streaks, the 

 periphery marked with a narrow dark band, a cream-white 

 band below it. The last embryonic whorl has forwardly- 

 descending stripes of dark brown and white; summit pale. 

 Surface not glossy, under the lens rather distinctly marked 

 with spiral and descending, waved striae, and irregular 

 growth-lines. Spire straightly conic, tapering to a subacute 

 apex. Aperture pallid purplish-gray and brown within ; outer 

 lip with a pale acute edge, unexpanded ; basal lip slightly ex- 

 panding, the columella slightly brown-tinted, having a rather 

 strong, callous fold above ; the edge reflected close to the in- 

 sertion. 



Length 17, diam. 9.8, aperture 8 mm. ; 6% whorls. 



Length 16, diam. 9 mm. 



East Maui: Auwahi, D. Thaanum. Cotypes in coll. A. N. 

 S. P. and Bishop Museum. Also in Thaanum collection. 



One of the largest Perdicellas, notable for its straightly 

 conic, rather slender spire, and the particular color-pattern. 

 The dark peripheral band, bordered with a white one, is in- 



