192 LAND REGIONS. 



Ariophanta) 50, Helix (sections Plectopjdis, Plectotropis. Burys- 

 toma, Trachia, Planispira, Corella, Oxj-tes ) 2 i , Boy sia 1 , Streptaxis 

 4, Ennea 6, Buliminiis 46, Cylindrus 5, Electra 53*, Clausilia 3 ; and 

 the following operciilated forms : Cyclotus 2, Myclaopoma 2, 

 Cyathopoma 21, Spiraeulum 3, Pteroeyclos 6, Alycasus 53, 

 Opisthopoma 5, Diplommatina 2, Nicida 6, Scabrina 1, Cyclo- 

 phorus 29, Lagocheilus 1, Ditropis 3, Tropidophora 1, etc.; in 

 all nearly 400 species. The fluviatile shells belong to the genera 

 Limntea, Planorbis, Ancylus, Camptoceras (special), Camptonyx 

 (special), Yalvata, Bythinia, Paludina, Amnicola, Stomatodon 

 (special), Tricula (special), Melania, Canidea and Clea (fresh- 

 water Buccinidse\ Paludomus, AmpuUaria, Neritina, Navicella, 

 Unio, Corbicula, Yelorita (special), Cyclas, Pisidium. 



The genera Tanysiphon, Scaphula (Arcidte), Novaculina 

 (Solenidse), Stenothyra and Oncidinm live in the estuaries. 

 Finally Cremnoconchus appears to be a terrestrial Littorina. 



The various provinces of the vast Indian peninsula show 

 remarkable diversity in altitude, climate and vegetation, and 

 the region might be subdivided, although it is throughout 

 characterized b}^ the presence of certain peculiar forms which 

 rather trenchantly separate it from other provinces. That 

 portion which undoubtedly presents the most distinctive 

 features is the island of Cejdon, which, like most insular faunas, 

 is particularl}^ rich in species. 250 forms are recognized from 

 this island, including 49 Nanina, 23 Cyclophorus, 16 Cataulus, 

 and 38 Paludomus (in Paludomus mostly varieties only . Two 

 of the groups of Helices, Acavus and Gorilla, are peculiar to the 

 island, Acavus including some of the most beautiful of the 

 Helicidffi. Cejdon has, perhaps, quite as much claim to be 

 treated as a distinct fauna, as several of the other regions of 

 Woodward and Fischer. 



13. Indo-Chinese Region. 



This region includes Assam, Burmah, Aracan, Pegu^ Cambodia, 

 Siam, Malacca, Singapore, Pulo Penang, Annain,' Laos, the 

 islands of the Nicobar and Andaman groups in the Gulf of 

 Bengal, etc. It is much richer in mollusks than even the Indian 

 peninsula, the operculated pulmonates especially being astonish- 

 ingly developed ; such as Cyclophorus, Lagocheilus, Pteroeyclos, 

 Rhiostoma, Alycseus, Diplommatina, Pupina, Rhaphaulus, etc. 

 The most abundant non-operculated pulmonates belong to the 

 genera Nanina, Helix, Amphidromus, Hypselostoma, Electra, 

 Clausilia, Yitrina, Streptaxis. The fresh-water gastropods are 

 Paludina, Ampullaria, Melania, Pachydrobia, Laeunopsis, Jul- 

 lienia, Canidea. The acephala are Unio, Pseudodon, Anodonta, 

 Arconaia, Solenaia, Dipsas, Cyrena, Coi'bicula, Scaphula (fresh- 

 water Area; and Modiola, of which a species lives in Lake Tonli- 



