The geographical distribution of animals, with a study of the relations ...

186 ZOOLOGICAL GEOGRAPHY. [part hi.that may fairly be considered as exclusively or characteristicallyPalsearctic.Reptiles and Amphibia.—The Palsearctic region possesses,proportion to its limited reptilian fauna, a full proportion ofpeculiar types. We have for instance two genera of snakes,Bhinechic and Halys ; seven of lizards, Trigonophis, Bsammodromus,Hyalosaurus, Scincus, Ophiomorus, Mcgalochilus, andBhrynocephalus ;eight of tailed batrachians, Proteus, Salamandra,Seiranota, Chioglossa, Hynobius, Onychodactylus, Geotriton,and Sieboldia ; and eight of tail-less batrachians, Bombinator,Pelobates, Didocus, Alytes, Pelodytes, Discoglossus, Laprissa, andLatonia.The distribution of these and other Palsearctic generawill be found in our second vol.chap. xix.Freshwater Fish.—About twenty genera of freshwater fishesare wholly confined to this region, and constitute a feature whichought not to be overlooked in estimating its claim to the rankof a separate primary division of the earth. They belong to thefollowing families :—Percidre (three genera), Acerina, Percarina,Aspro ; Comephoridie (one genus), Comephorus, found only inLake Baikal ; Salmonidse (three genera), Brachymystax, Luciotrutta,and Plecoglossus ; Cyprinodontidse (one genus), Tellia,found only in Alpine pools on the Atlas Mountains ;inCyprinidse(thirteen genera), Cyprinus, Carassus, Paraphoxinus, Tinea,Aehilognathus, Bhodeus, Chondrostoma, Pseialoperilampus, Ochetebius,Aspius, Alburnus, Misgurnus, and Nemachilus.Summary of Balccarctic Vertebrata.—Summarising these details,we find that the Palsearctic region possesses thirty-fivepeculiar genera of mammalia, fifty-seven of birds, nine ofreptiles, sixteen of amphibia, and twenty-one of freshwaterfishes; or a total of 138 peculiar generic types of vertebrata.Of these, 87 are mammalia and land-birds out of a totalof 274 genera of these groups ; or rather less than one-thirdpeculiar, a number which will serve usefully to compare withthe results obtained in other regions.In our chapter on Zoological Ptegions we have already pointedout the main features which distinguish the Pakearctic from theOriental and Ethiopian regions. The details now given will