AMASTRA, OAHU. 221 



color-factor is inhibited without otherwise changing the ani- 

 mal. In this case the peculiarity has been perpetuated in a 

 race. Specimens from Kalaikoa (fig. 19) and Wahiawa (fig. 

 20) are figured. 



Under the cuticle the shell is white below the periphery, 

 rusty red-brown, uniform or streaked above it. Over the 

 whole there is a light greenish-yellow cuticle, and on the last 

 whorl there may also be a very thin, light brown, partially 

 deciduous outer cuticle. The spire is streaked with rust- 

 brown ; the embryonic whorls yellow-corneous or light brown. 

 The outlines of the spire are generally concave. The colu- 

 mella and lip have a rose tint. 



Sometimes there is a rusty belt below the periphery, the 

 latter then marked with a pale band or zone. Size and shape 

 vary as in A. s. nigrolabris. 

 Length 18.7, diam. 11 mm, 

 Length 18, diam. 12 mm. 



The columella is heavily calloused above the rather small 

 plait, and it occasionally has one or two small tubercles, or a 

 low, narrow fold above, such as occurs in some specimens of 

 A. s. nigrolabris. The umbilicus may be open or closed. 



Dr. Newcomb (1858) first united A. rudis var. b, A. chloro- 

 tica and A. albida.. In 1893 Mr. Baldwin subordinated rudis, 

 chlorotica and albida to nigrolabris as color- varieties ; but 

 Pfeiffer's names are prior to nigrolabris. It is, however, true 

 that nigrolabris is the parent form, the others derivatives. 

 Mr. Thwing records A. chlorotica and A. albida from Mt. 

 Kaala. It is not likely that he had the form here identified 

 as chlorotica. The original description of albida follows : 



Achatinella albida Pfr. Shell perforate, ovate-turrite, thin, 

 irregularly striate, whitish streaked with a pale fulvous epi- 

 dermis. Spire conic, the apex somewhat acute, the suture 

 very slightly crenulate. Whorls 6, the upper flat, following 

 more convex, the last scarcely % the total length, rotund, ob- 

 soletely subangular at the periphery. Aperture a little ob- 

 lique, sinuate-oval. Oolumellar fold median, laminiform, 

 oblique. Peristome simple, unexpanded, the columellar mar- 

 gin shortly reflexed, nearly free. Length 17, diam. 9y 2 mm. 

 Sandwich Is., Mr. D. Frick, Cuming coll. (Pfr.). 



