Dr. A. Giinther on the Geographical Distribution of Reptiles. 239 



a reason for establishing a separate region, small as regards the geogra- 

 phical area, rich as to its animal and vegetative life, if the still hidden 

 })arts should prove to be as peculiar as that which we know. Sancinia, 

 Pelophilus, and Lcnujaha constitute genera not represented by other 

 species in other provinces. If we look at the forms common to other 

 regions, we find them all to be Tree-snakes, having the allied species 

 spread over the tropical regions in the west or east. 



III. Indian or Middle Palisotropiccd Region (Regio Indica). 



Characteristic forms. — Chersijdrus, Acrochordus, Xenodermus, 

 Python, Cliftia, Cusoria, Gonyylophis, Cfothonia, Cylindrophis. 

 Calamaria, Rhabdion, Brachyorrhos, Aspidura, Ilapfocercus, Ela- 

 poidis, Trachischium, Oliyodon, Siinotes, Ferania, Homalopsis, Phy- 

 tolopsis, Tropido2}his, Hypsirhina, Fordonia, Raditia, Miralia, 

 Xenodon (with keeled scales), Gonyosoma, Fiwjjhrys, Psawmody- 

 nastes, Passerita, Leptoynathusi indicus, Amblycephalus, Parens, 

 Jlologerrhum, Lycodon, Tetruyonosoma, Leptorhyton, Ophites, 

 Cercaspis, Cydocorus, Hamadryas, Biniyarus, Naja trijjudicms, 

 Flaps (with thirteen rows of scales). Hydrid^e : Trimesnrvs, Par/as, 

 Meycera, Atropos, Triyonocephalas, Dahoia (except Z>. xanthina, 

 Gray). 



Forms common to other regions. — Rhabdosoma, Cerberus, Co- 

 luber, Flajjhis, Spilotes, Coryphodon, Chrysopelea, BendropJiis, 

 Bryophis, Eudijjsas, Dipsas, Dipsadomorphus, Ediis. 



AVhether the Indian region really is richer in peculiar generic 

 and specific forms than the African one, or whether this difference 

 is caused only by our more extended knowledge of the former, 

 the future will show ; for the present it is not even rivalled by 

 the South American region : for, taking the area of the Indian 

 region at 4,000,000 square miles and the number of species of 

 Snakes at 240, we have on an average a single species to every 

 17,000 square miles, or 21 species to the same area for which we 

 found only one species in the Palsearctic region, and 9 for the same 

 area in the iEthiopian. The ratio between the different sections of 

 the Snakes shows that, in comparison with Africa, the relative 

 number of Boina is diminished, their ratio to the Colubrina being 

 1:12: but that of the Viperine Snakes has as much increased as 

 the absolute one ; each seventh species belongs to this truly venom- 

 ous section (I : 6). Quite a new form of snakes enters nito this 

 faima — the Hydrides : organized for living in the sea, they are 

 seldom found on the coasts, and we do not yet know whether they 

 approach the beach occasionally, or when obliged by certain physio- 

 logical functions. But being constant inhabitants of the sea, they are 

 endowed with active as well as with passive locomotion to enable 

 them to traverse greater distances than the snakes living on dry 

 ground ; and therefore it is not to be wondered at that we find not 

 only the section in general, but the single species spread far beyond 

 its actual native ground — namely the sea between the southern coast 

 of China and the northern one of New Holland — and extending to 



