362 



bartsch: land shells of Palawan passage 



Measurements of a large series of specimens from these islands 

 show that there is a decided difference in the size of the specimens 

 obtained on the three islands. The difference is probably best 

 expressed in table 1. 



TABLE 1 



LOCALITY 



Candaraman. 



Caxisigan 



Bekin 



GREATER 

 DIAMETER 



17.76 

 17.12 

 15.95 



These differences I consider sufficient to demand a trinomial 

 designation. The specimens from Candaraman are Amphidro- 

 mus quadrasi quadrasi Hidalgo, the type locality for this sub- 

 species. Those from Caxisigan may be known as Amphidromus 

 quadrasi caxisiganensis Bartsch^ and those from Bekin as Amphi- 

 dromus quadrasi ledyardi Bartsch.'* 



The second group we- may consider typified by Amphidromus 

 versicolor Fulton. Specimens of this group always have the 

 extreme tip dark brown ; the rest of the turns may be white, pale 

 yellow or wax yellow, or variously variegated; in the latter case 

 the two or two and a half turns succeeding the dark tip are usually 

 uniformly flesh-colored, while the ground color of those following 

 may be white, yellow, green, or red, or sometimes several of these 

 colors, one overlying the other, may be present ; in each instance, 

 if otherwise than white, the tint gradually becomes intensified 

 toward the aperture. The whorls between the first two and the 

 last may be unicolor or they may be marked by axial lines, bands, 

 or forked flammulations of chestnut brown. The base may be uni- 

 color or spirally banded with yellow, green, brown, or red. The 

 columellar area may be white or edged with yellow, green, brown, 

 or red. The lip may be white, pink, or purple, while the interior 

 ranges from w^hite through pearl gray, pink, pale purple, to spinel 

 red. The general impression which one gains by looking at a tray 

 of mixed specimens is a rainbow effect. 



3 Type, Cat. No. 215603, IT. S. National Museum. 

 * Type, Cat. No. 215606, U. S. National Museum. 



