04 



subacute: spire well elevated, with the outlines rather convex: 

 whorls four and one-half, rather convex, with a well impressed su- 

 ture : aperture rather large, semicircular, with the notch at the base 

 of the columella scarcely perceptible or wanting: labrum moderately 

 reflected and thickened. 



Mean divergence about 120^; height ,2 inch; greatest breadth 

 .285 inch ; least breadth .24 inch. 



A^'ar. intermedia ; with a very small but distinct obtuse notch ; the 

 spire is less elevated, and the shell is larger and thinner. We should 

 Lave considered this a distinct species, but are unable to find its limits 

 in a series of specimens. It is intermediate between the type of the^ 

 species and H. soUtaria, the latter having an acute-angled notch. 

 Height .24 inch; greatest breadth .34 inch ; least breadth .29 inch. 



I am indebted to the Hon. Edward Chitty for the opportunity of 

 examining all the Geomelaniae, which he has collected. The differ- 

 ent types graduate into each other, so as to render the establishment 

 of species extremely difficult. The value of the differences appears 

 to be in the following oi-der ; 1, of the linguiform part*" of the labrum ; 

 2, of sculpture ; 3, of form ; 4, of size. The color is absolutely the 

 same in all the species which I have seen. There are four distinct 

 types represented by G. clegans, G. Beardsleana, G. minor, and G. 

 typica or G. fortis. 



Geomelania fortis. — Shell elongate conic: whitish: with, on 

 each whorl, about thirty-six rather slender transverse arcuated ribs : 

 spire with rectilinear outlines : apex truncate with the loss of about 

 eight whorls : whorls remaining Beven, moderately convex, ^'ith a 

 well impressed suture : aperture ovate, widely and deeply effuse : 

 labrum well expanded and reflected; with the linguiform part at the 

 anterior extremity, excessively produced obliquely and downwards, 

 rather narrow, acute : labium well thickened, .^lightly separated front 

 the penult whorl. 



Mean divergence about 12^^; length .6 inch ; greatest breadth .18 

 inch; least breadth .15 inch. 



Geomelania magna. Shell elongate conic : Avhitish : with, on 

 each whorl, about thirty-eight rather slender transverse much arcua- 

 ted ribs : spire with rectilinear outlines : apex truncate with the loss 

 of eight whorls : whorls remaining six and one half, moderately con- 

 vex, with a well impressed suture : aperture ovate, widely and deeply 

 effuse: labrum well expanded and reflected; with the linguiform 



* This ii iiiore toiietlly clciioiuiiiatcd a })uit of ihan r,n aipaidu'jc to the labiiira. 



