ACHATINELLA BULIMOIDES. 159 



white .border about an eighth of an inch in width around the 

 outside of the lip, whereas in A. ~bulimoides and other allied 

 species the color becomes darker on this portion of the shell 

 though the lip itself be white. Dextral specimens are very 

 rare. The 'color of the darker portion of the shell varies in 

 different specimens from a dirty cream to slate color, but the 

 ashy color given in the description is the most 'Common ' ' ( Gu- 



The color of the darker, lower portion of the shell varies 

 through several shades resembling purple-drab, vinaceous 

 purple and slate-drab of Ridgway's Color Standards. These 

 tints are produced by films of white laid over a brown layer, 

 which may be exposed by scraping. The lip is white or nearly 

 so typically, but in one lot it is fleshy-brown. The white 

 border behind the lip mentioned by Gulick is by no means con- 

 stantly present; often the dark color runs to the lip, which 

 may have a narrow brown edge outside, but not so wide or 

 dark as in ovata. The summit is usually light yellowish- 

 brown ; sutural margin well defined, bluish-white. Lip some- 

 what expanded, as in A. ovata, having a moderate 'Callus 

 within. The parietal callus is generally imperceptible. Be- 

 tween 3 and 4 per cent of the shells seen are dextral. Length 

 22, diam. 13 mm. ; 6% whorls. 



Occasionally the dark color is restricted to a peripheral 

 band, or it may disappear altogether, leaving the shell pure 

 white. More often some brown remains on the spire. In a 

 few shells the parietal callus is rather thick and brownish at 

 the edge. The above notes are from the large series collected 

 by Gulick. 



A. b. obliqua was described from a colony in which the sin- 

 istral form very largely predominated. Mr. Gulick described 

 shells from a colony in which the dextral form prevailed as 

 A. oomorpha. While not exactly like typical obliqua, it does 

 not seem sufficiently differentiated to require a name. The 

 original account follows. 



A. oomorpha Gulick. PI. 28, figs. 10 to lOc. " Shell dex- 

 tral, perforate, ovate, solid, shining, striated ; ash or ash-brown 

 with two obscure brown bands, white beneath the suture. 



