64 HELIX-HELICOPHANTA. 



H. (Helicophanta) bicingulata E. A. SMITH, Proc. Zool. Soc. Lond. 

 1882, p. 380, t. 21, f. 13, 14. IT. cornu-giganteum ANGAS, P. Z. S. 



1877, p. 527 (not of Chemnitz). H. guestieriana ANGAS, P. Z. S. 



1878, p. 312 (not of Crosse). 



This is the species erroneously considered by Mr. Angas to be the 

 H. guestieriana of Crosse, which much more closely resembles H. 

 ibaraoensis of the former author. H. guestieriana is a more globose 

 shell, with a higher penultimate whorl, a shorter aperture, a smooth 

 columella, and a smooth callosity upon the body-whorl, which is en- 

 circled by several slightly raised ridges of more equal size than in 

 H. bicingulata. The granular, slightly arched-forward columella in 

 the latter species, the obliquely indented surface of the body-whorl, 

 and the two very conspicuous brown slightly raised girdles distinguish 

 this from the allied forms, H. cornu-giganteum, betsileoensis, ibara- 

 oensis, and guestieriana. The first two are openly umbilicated, the 

 third generally imperforate (in about 50 specimens I have seen a 

 few with a narrow perforation) ; and the last is said to be " nar- 

 rowly subrimate." H. betsileoensis has the columella granular, as 

 in the present species; in the other three it is smooth. In H. 

 ibaraoensis the callus uniting the columella and the outer lip and 

 spreading over the whorl within the aperture is conspicuously gran- 

 ulated, and the epidermis is nearly black toward the lip. (Smith.) 



Smith's description and comments are given above. It is scarcely 

 necessary to add any further distinguishing marks. The species has, 

 however, so great a range of variation that certain of its forms may 

 embarrass the student. One of these is figured on pi. 64, fig. 63. 

 This is a chestnut-brown shell, becoming olive-brown on the penul- 

 timate and earlier part of the last whorl, darker beneath. The two 

 girdles are not nearly so well marked as in the type ; the form is 

 less depressed. Alt. 40, greater diam. 68 mill. 



Another form (pi. 64, fig. 62) is very much smaller, and the spiral 

 girdling quite different, being multicingulate, like H. guestieriana,. 



Alt. 35, greater diam. 60 mill. 



It is altogether likely that H. vesicalis Lam. ( Vide Ferussac, His- 

 toire, t. 10, figs. 3a, b, and Chenu, Illust. Conchyl., Helix, t. l,figs. 

 1, 2, 3) is a form of this same species. It is certainly not correctly 

 placed in the synonymy of H. cornu-giganteum Chem. 



