381 



III. Indian or Middle PaUeotropieal It>-</i<>,i ( Elegio [ndica). 



Characteristic forms. — Chersydnu, Aerochordue, Yenodertmu, 

 Python, ('lift m, Ctuoria, Gongylophu, Clothonia, Cylindrophia. 

 Calamaria, Rhabdion, Braehyorrhoa, Atpidura, Haptocereua, Elu- 

 poidie, Traehiaehium, Qligodon, Simotea, Ferania, Homalopeie, PAy- 

 tolopaia, Tropidophia, Hyprirhina, Fordonia, Raclitia, Miralia, 

 Xenodon (with keeled scales), Gonyoeoma, Euophrye, Peammody- 

 »ns(es, Passerita, Leptoanathua '. indicua, Amblycephalus, Pareas, 

 llologerrhun,, Lycodon, Tetragonoaoma, Leptorhyton, Ophites, 

 Cercaspis, Cyclocorus, Hatnadryas, Bungarug, Naja tripudians, 

 Elaps (with thirteen rows of scales). Hydkiu.k, Trimesurva, Pariaa, 

 Meycera, Atropoa, Trigonoeephaloa, Daboia (except D, xanthine, 

 Cray). 



Forms common with other regions. — Rhabdoaoma, Cerberua, Co- 

 luber, Elajj/iis, Spilotes, Coryphodon, Chryaopelea, Dendrophia, 

 Dryophia, Eudipaoa, Dipsos, Dip.sadomorphus, Echia. 



Whether the Indian region really is richer in pecnliar 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 l>\ 

 the South American rea;ion : 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 the average a single species to each 

 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 .Ethiopian. The ratio between the different sections of 

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

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

 = 1 : 12, but that of the Viperine Snakes has as much enlarged as 

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

 ous section (1 : 6). Quite a new form of snakes enters into this 

 fauna — the Hydride : organized for living in the sea, they arc 

 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 ai that we find not 

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

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

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

 the south of the Australian region, and far between the tropical 



islands of the Pacific. A certain proximity to land appears t<> be 

 necessary for their lite, as tbcv are never found in those wide marine 

 spaces which are void of islands, not being able by traversing them 

 to spread into the Neotropical or /Ethiopian regions 4 ; and thus the] 



* During the printing of this paper, I first heard of S.a-sn.i a the 



western shares of America. They were observed in considerable nmnben bj \t. 

 Salle ami Mr. Salvia, .it different times, from iteamen 'lie Hay of 



