ACHATINELLA CASTA. 239 



copied from Mr. Smith's, the specimens having been given by 

 Mr. Gulick. A. ligata has usually been considered' a form of 

 A. bellula by Hawaiian conchologists, but the figures and de- 

 scription agree with a form of casta from Waimano. A set 

 of four in the Gulick collection, three dextral and one sinistral, 

 seem to me to belong to casta. The type lot, from Gulick, 

 was "reported to be from Waimalu,' which is further west 

 than A. bellula is known, and near the eastern limit of the 

 range of casta. It seems that towards its eastern limit A. casta 

 approaches A. bellula in characters, and is sometimes dextral. 

 A. ligata was based upon specimens of this somewhat inter- 

 mediate form. The dextral form probably occurs too inti- 

 mately blended with casta to be segregated as a subspecies. 



1 A. pygmcca Smith. PL 49, fig. 16. Shell sinistral, ovate- 

 conic, glossy, striated with extremely fine growth and trans- 

 verse lines, yellow. Suture lightly margined. Whorls 5%, 

 convex, the first 3 1/2 white. Aperture white ; peristome slightly 

 bordered ; columellar fold moderately large, rose. Length 14, 

 diam. 8 mm. Var. : shell whitish, encircled above the per- 

 iphery with a line, below with a zone of brown. Waipio' 

 (Smith}. 



The type specimen is figured. It measures 14.7 mm. long, 

 8 wide, and differs from unicolored Waiawa casta only in the 

 smaller size. Possibly pygmcea can be retained as a varietal 

 name for the small western casta, if size proves to be corre- 

 lated with distribution, which is not likely. Waipio is near 

 the western limit of A casta. Mr. Spalding collected a similar 

 small form of casta in the western ravines of Waiawa, but it is 

 not quite identical, having the spire noticeably broader. 

 However, the variation from pygmcea is not greater than 

 among individuals in other Waiawa colonies. 



A. concolor E. A. Smith, [pi. 41, fig. 12, type]. "Shell 

 sinistral, ovate-conic, glossy, striated with growth-lines and 

 transversely, even on the first 3 whorls ; yellow ( sometimes 

 streaked with dilute brown) ; suture distinctly margined. 

 Whorls 6, convex, the first 3 whitish. Aperture white ; peris- 

 tome thin, the columellar fold strong, roseate. Length 19, 

 diam. 10 mm. Ewa, Frick.' (Smith.} 



