266 AMASTRA, MOLOKAI. 



costulate. The later whorls have weak growth-striae. Length 

 20, diam. 10.9, aperture 9.2 mm. ; 7 whorls. 



In a longer specimen, pi. 49, fig. 12, the first 3% whorls 

 are brown, dark red-brown at apex; next two whorls white, 

 lightning-marked with zigzag black stripes; last 1% whorls 

 covered with a dense black cuticle, worn off in front of the 

 aperture, exposing a white patch. The penultimate whorl is 

 convex, those above it only very slightly so, the last whorl 

 being somewhat compressed in the middle. Aperture white ; 

 axis perforated. Length 21.9, diam. 10.9, aperture 8.3 mm. ; 

 7 whorls (no. 104684, A. N. S. P.). 



A. nubilosa, a species resembling uniplicata in shape and 

 size, differs by characters of the embryonic whorls. 



A. uniplicata is closely related to A. pullata, from which it 

 differs chiefly by its much narrower contour. It is not allied 

 to A. biplicata as Hartman supposed. 



Series of A. assimilis. 



The Molokaian Amastrse having zigzag or angular markings 

 are a most intricately related group of forms, which can only 

 be understood when large collections 'are made and the dis- 

 tribution of the several forms 'adequately mapped. At pres- 

 ent we know of them scarcely anything of value to science; 

 merely that the series is developed in a rich variety of forms 

 in eastern Molokai, that these races vary widely in ground- 

 color and markings, and that some of them show close affinity 

 with races of Maui. Most of the species and subspecies which 

 have been established are merely tentative. 



Through A. borcherdingi and uniplicata this group con- 

 nects with the pullata series. 



74. A. BORCHERDINGI Hyatt & Pilsbry, n. sp. PL 41, figs. 1, 

 2, 3, 4; pi. 40, figs. 2-6. 



The shell is ovate-conic, narrowly perforate or closed, 



moderately strong; upper 3 or 4 whorls reddish-brown 



(rarely pale yellow), the last two white with a faint flesh tint, 



elaborately figured with angular, zigzag or interrupted dark 



