THE NAUTILUS. 



VOL. XII. JUNE, 1898. No. 2. 



A LIST OF LAND AND FRESH WATER SHELLS OF ENGANIO WITH 

 DESCRIPTIONS OF NEW SPECIES. 



BY JOHN B. HENDERSON, JR. 



The shells forming the subject of this paper were collected in the 

 Island of Enganio by Mr. William Doherty, by whom they were 

 sent to Mr. Aldrich, of Birmingham, Ala. Enganio, or Pulo Telan- 

 jang, is a small island surrounded by deep sea, off the southwest 

 coast of Sumatra, about one hundred miles west of Benkoelen. Mr. 

 Doherty has published in the "Asiatic Journal " of Bengal, 1886, 

 his observations upon this island. From geological features and 

 the faunal relations of the birds and insects collected, he concludes 

 that Enganio forms a continuation of a submerged mountain chain, 

 isolated peaks of which constitute the present Nias group. He finds 

 the fauna of Enganio to be more closely related to that of the Anda- 

 mans and the Nicobars than to that of Sumatra, and also to possess 

 decided Javau affinities. He finds other evidence of the long isola- 

 tion of this island from either the mainland or neighboring islands. 

 A study of these shells tends to confirm the correctness of hia views. 

 The land and fresh water mollusks of Perak, and, in general, of the 

 entire Malay Peninsula, bear a striking resemblance to those of 

 Enganio. I have been unable to learn anything about the inollus- 

 can fauna of the Nias group, which, if known, would probably furn- 

 ish additional evidence of the one-time closer connection of Java 

 and the mainland through Enganio, the Nias group, the Nicobara 

 and the Andamans. As will be seen, several of the species herein 

 enumerated are identical with Javan forms, and others strongly 



