OP CONCHOLOGY. 109 



DESCRIPTIONS OF NEW SPECIES OF TERRESTRIAL MOL- 

 LUSCA FROM THE ANDAMAN ISLANDS, INDIAN AR- 

 CHIPELAGO. 



BY GEO. W. TRYON, JR. 



The small collection of shells from the above locality I believe 

 are almost the only specimens of the Mollusca of the Andamans 

 which have been seen by any naturalist, as I cannot discover 

 any species attributed to these islands in the various mono- 

 graphs.* In view of this fact, and of the isolation of these is- 

 lands, we may rationally conclude that most of the shells which 

 may be discovered there hereafter will be peculiar to them and 

 new to science. 



The Andaman Islands are a densely wooded group, situated 

 in the lower part of the Bay of Bengal, nearly two hundred 

 miles south-west of Cape Negrais, and about the same distance 

 north of the Nicobar Islands. They are scantily populated by 

 barbarous tribes. Area about 3000 square miles. A British 

 naturalist, Dr. Heifer, lost his life, a few years ago, from an at- 

 tack of the natives while endeavoring to investigate their natural 

 history. The mollusca are of course of Indian types. 



1. Rhysota {Helix) Chambertinii, Tryon. — PI. 10, fig. 2. 



Desc7'iption. — Shell turbinately depressed, rather solid, whorls 

 five, convex, with deep sutures, the last whorl slightly angulate 

 on the periphery. Surface marked with rugose growth lines, 

 decussated by numerous close undulating revolving strise. Aper- 

 ture oblique, oval ; lips simple, thickened near the narrow umbi- 

 licus. Color chestnut brown, white within. 



Dimensions. — Diam. 31, alt. 21, mill. 



* The only conchological mention of the islands is in a paper by Mr, 

 W. H. Benson (Annals and Mag. Nat. Hist. 3d ser. vi, 190, 1860), con- 

 taining descriptions of Helix Helferi, Streptaxis Andamanica, and Heli- 

 cina Andamanica, and in the Mai, Blatter is the description of a Helix 

 from the same locality. 



