186 ZOOLOGICAL GEOGRAPHY. [PART III. 
that may fairly be considered as exclusively or characteristically 
Palearctic. : 
Reptiles and Amphibia—The Palearctic region possesses, in 
proportion to. its limited reptilian fauna, a full proportion of 
peculiar types. We have for instance two genera of snakes, 
Rhinechie and Halys; seven of lizards, Trigonophis, Psammo- 
dromus, Hyalosaurus, Scineus, Ophiomorus, Megalochilus, and 
Phrynocephalus ; eight of tailed batrachians, Proteus, Salaman- 
dra, Seiranota, Chioglossa, Hynobius, Onychodactylus, Geotriton, 
and Sieboldia ; and eight of tail-less batrachians, Bombinator, 
Pelobates, Didocus, Alytes, Pelodytes, Discoglossus, Laprissa, and 
Latonia. The distribution of these and other Palearctic genera 
will be found in our second vol]. chap. xix. 
Freshwater Fish—About twenty genera of freshwater fishes 
are wholly confined to this region, and constitute a feature which 
ought not to be overlooked in estimating its claim to the rank 
of a separate primary division of the earth. They belong to the 
following families :—Percide (three genera), Acerina, Percarina, 
Aspro; Comephoride (one genus), Comephorus, found only in 
Lake Baikal; Salmonide (three genera), Brachymystax, Lucio- 
trutta, and’ Plecoglossus ; Cyprinodontide (one genus), Tedlia, 
found only in Alpine pools on the Atlas Mountains; Cyprinide 
(thirteen genera), Cyprinus, Carassus, Paraphoxinus, Tinea, 
Achilognathus, Rhodeus, Chondrostoma, Pseudoperilampus, Oche- 
tebius, Aspius, Alburnus, Misgurnus, and Nemachilus. 
Summary of Palearctic Vertebrata—Summarising these de- 
tails, we find that the Palearctic region possesses thirty-five 
peculiar genera of mammalia, fifty-seven of birds, nine of 
reptiles, sixteen of amphibia, and twenty-one of freshwater 
fishes; or a total of 138 peculiar generic types of vertebrata. 
Of these, 87 are mammalia and land-birds out of a total 
of 274 genera of these groups; or rather less than one-third 
peculiar, a number which will serve usefully to compare with 
the results obtained in other regions. 
In our chapter on Zoological Regions we have already pointed 
out the main features which distinguish the Palearctic from the 
Oriental and Ethiopian regions. The details now given will 
