296 THE CAUCASUS AND THE CASPIAN SEA chap. 



(which is very abundant in Austro-Hungary), Pomatia (Greece 

 and Asia Minor), and Anchistoma. Macular ia is comparatively 

 scarce, but is represented in Greece by one very large form 

 (^Codringtonii Gray). Zonites proper has its metropolis in this 

 sub-region, and the Danube basin contains one or two species 

 of Melania and Lithoglyphus. BuUminus is abundant through- 

 out the sub-region, in the sub-genera Zebrina, Napaeus^ 2Iastus, 

 and Chondnda. Several striking forms of Zehrina (^Ena^ are 

 peculiar to the Crimea. 



((?) The Caucasian Province. — The limits of this province 

 can hardly be exactly defined at present. It appears, however, 

 to include the whole line of the Caucasus range, Armenia, and 

 North Persia. 



The land Mollusca are abundant and interesting. Among the 

 carnivorous genera are four species of Daudebardia^ a Glaiidina^ 

 and three peculiar forms of naked slug, Pseudomilax, Trigono- 

 chlamys^ and SelenocJdamys. There is a single Parmacella^ the 

 same species as the Mesopotamian, and a good many forms of 

 Limax. Vitrina and Hyalinia are well represented, and the pre- 

 dominant groups of Helix are Euloto, Cartusiayia, Xeroj^hila^ and 

 Pruticocampylaea, the last being peculiar. Clausilia and Pupa 

 are rich in species, together with BuUminus of the Chondrula 

 type. One Clausilia of the Phaedusa section, together with a 

 Macrochlamys (Transcaspian only), a Corbicula, and a Cyclotus, 

 show marked traces of Asiatic affinity. There is one species 

 each of Acicula and Cyclostoma, and one of Pomatias. 



The Caspian Sea, like Lakes Baikal and Tanganyika, is dis- 

 tinguished by the possession of several remarkable and peculiar 

 genera. The sea itself, the waters of which are brackish, is 80 

 feet below the level of the Black Sea, and is no doubt a relict of 

 what formed, in earlier times, a very much larger expanse of 

 water. Marine deposits containing fauna now characteristic 

 of the Caspian, have been found as far north as the Samara bend 

 of the Volga. It is probable, therefore, that in Post-pliocene 

 times an arm of the Aralo-Caspian Sea penetrated northward up 

 the present basin of the Volga to at least 54° N. The Kazan 

 depression of the Volga (55° N.) also contains characteristic 

 Caspian fossils.^ According to Brusina,^ the Caspian fauna, 



1 Netchayeff, Kazan Soc. Nat. xvii. fasc. 5. 



2 Fauna der Congerien-Schichten, p. 142. 



