AMASTRA, MAUI. 283 



is also dirty; a character recalling Pterodiscus, and lending 

 some little evidence in favor of the view that Pterodiscus 

 arose from ancestral obesa. 



Dr. C. M. Cooke informs me that the shell figured by Mr. 

 Thwing as A. heliciformis, now in the Bishop Museum, is A. 

 obesa. 



85. A. AGGLUTINANS (Newcomb). PI. 36, figs. 11, 12. 



Shell narrowly umbilicate, depressed, angular at the peri- 

 phery, pale yellow under a thin light-brown cuticle, the spire 

 reddish-brown ; more or less daubed with earth, which forms 

 an irregular, broken flange at the periphery. Spire short, 

 concavely conic, the finely striate, convex embryonic whorls 

 projecting. Last whorl rather coarsely, irregularly striate, 

 subacutely angular at the periphery, descending in front. 

 Aperture white within, the outer lip but slightly thickened. 

 Columella white, oblique, bearing an oblique fold. Length 

 8.5, diam., not including agglutinations, 10 mm. ; whorls 5. 



West Maui: Wailuku (Gulick). 



Achatinella obesa var. agglutinans NEWCOMB, P. Z. S., 

 1853, p. 143, pi. 23, fig. 39a. Amastra carinata GULICK, P. 

 Z. S., 1873, p. 83 (no description). 



This very peculiar species has characters which must have 

 belonged to the ancestors of Pterodiscus. It is remarkable in 

 Amastra for the peripheral keel and the bedaubed surface. 

 Gulick based his species upon Newcomb 's description and 

 figure. The original description follows : ' ' Var. agglutinans. 

 Shell somewhat, carinated on the last two whorls, with the 

 keel extended by agglutinations, giving it a pagoda4ike 

 form." 



The figures were drawn from a specimen received from 

 Newcomb. Although this form has been united with obesa as 

 a variety by Xewcomb and Baldwin, the series of both ex- 

 amined leads us to agree with Gulick and Sykes that it is 

 distinct. There seems no good reason for changing the name 

 originally given by Newcomb. 



Section HETERAMASTRA Pilsbry (p. 141). 

 Sinistral Amastrae with rather oblong, delicately costulate 



