186 
ZOOLOGICAL GEOGRAPHY. 
[part III. 
that may fairly be considered as exclusively or characteristically 
Palaearctie. 
Reptiles and Amphibia . — The Palaearctie region possesses, in 
proportion to its limited reptilian fauna, a full proportion of 
peculiar types. We have for instance two genera of snakes, 
Rhinechis and Halys ; seven of lizards, Trigonophis, Psammo- 
dromus, Hyalosaurus , Stincus, Ophiomorus , Megalochilus , and 
Phrynocephalus ; eight of tailed batrachians, Proteus, Salaman - 
dm, Sewanota, Chioglossa, Hynobius, Onyckod aetylus, Geotriton, 
and Sieboldia; and eight of tail- less batrachians, Bombinator, 
Pelobates, Didocus, Alytes, Pelodytes, Discoglossus, Laprissa, and 
Latonia. The distribution of these and other Palaearctie 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 : — Percidae (three genera), Acerina, Per carina, 
Aspro ; Comephoridae (one genus), Comephorus, found only in 
Lake Baikal ; Salmonidae (three genera), Brachymystax , Lucio- 
trutta, and Plecoglossus ; Cyprinodontidae (one genus), Tellia, 
found only in Alpine pools on the Atlas Mountains ; Cyprinidai 
(thirteen genera), Cyprinus, Car asms, Paraphoxinus, Tinea, 
Ackilognatlms, Rhodeus, Chondrostoma, Pseudoperilampus , Oche- 
tebius, Aspius, Alburnus, Misgurnus, and Nemaehilus . 
Summary of Palcearctic Vertebrata. — Summarising these de- 
tails, we find that the Palaearctie 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 Kegions we have already pointed 
out the main features which distinguish the Palaearctie from the 
Oriental and Ethiopian regions. The details now given will 
