152 Helix Jamaicensis, etc. 



All the localities mentioned are in the southwestern corner 

 of Colorado (Inger&oll ! ) . 



Remarks. This species was discovered by Mr. Ernest 

 Ingersoll, Naturalist of the United States Geological Survey 

 of the Territories, under Professor Hayden. It can scarcely 

 be compared with any known North American species. 



The magnified figures herewith given, from drawings made 

 by my friend Mr. A. Ten Kyck Lansing, faithfully represent 

 the shell. 



At first sight I was disposed to consider the species a 

 Zonites, but examination of the animal by Mr. W. G. Binney 

 proved it to belong to the Helicinm; I am indebted to him 

 for the following particulars : — 



Jaw low, wide, slightly arcuate, ends slightly attenuated ; whole anter- 

 ior surface with about 22, broad, flat, slightly separated ribs, whose ends 

 denticulate either margin. This form of jaw is unusual among the Hrti- 

 cince. It is of same type as in H. Lamingi (Ann. Lye. N. II. of N. Y. 

 XI, 74, fig. 2.) 



Lingual membrane long and narrow. Teeth about 16-1-16. Centrals 

 as usual in the Ilelicince: the side cusps and cutting points are well de- 

 veloped, the base of attachment longer than wide. Laterals of same 

 type, but unsymmetrical and consequently only bicuspid. The change 

 from laterals to marginals is very gradual, there being no splitting of the 

 inner cutting point. Marginals low, wide, with one inner, long, blunt 

 cutting point, and one outer small blunt cutting point. 



Geostilbia Gundlachi, Pfeiffer. 



Through the kindness of Dr. H. E. van Rygersma, I 

 have lately received specimens of this species, with the ani- 

 mal (in alcohol), collected by him in the Island of St. Mar- 

 tin. The species was described as Achatinct Gundlachi by 

 Pfeiffer in 1850. 



In 1867, M. Crosse established the genus Geostilbia 

 (Jour, de Conch., p. 184), for a species from New Cale- 

 donia, and referred Achatina Gundlachi to the same genus 

 in 1874 (1. c. p. 88). 



