224 HISTORY OF THE EUROPEAN FAUNA. 



closely related to the arctic marine Mysis oculata. 

 According to Professor Sars, the genus Mysis as a 

 whole may be regarded as arctic in character. The 

 occurrence of these two species, therefore, in his 

 opinion, points to a recent connection of the Caspian 

 with the Glacial Sea. 



A large number of other crustaceans have been 

 described by the same author from the Caspian. Of 

 the order Cumacea, which is exclusively marine, 

 ten species are mentioned, but none of these seems 

 to range beyond the Caspian. Among the smaller 

 species of crustaceans, a minute pelagic copepod 

 (Limnocalanus grimaldii) also inhabits the Baltic 

 and the Arctic Ocean. The marine isopod Idctea 

 entomon, related to the common wood-louse, has a 

 similar distribution. 



Genuine Arctic species of Fishes do not seem to 

 occur in the Caspian, though some, viz., Clupea 

 caspia y Atherina pontica, Clupionella Grimmi, and 

 Syngnathus bucctilentus, are almost certainly the 

 descendants of marine forms. 



The Seal of the Caspian (Phoca caspica) is closely 

 allied to the Arctic Seal, and its presence alone in 

 that sea indicates that at no very distant date at 

 any rate since pliocene times a closer connection 

 with the Arctic Ocean existed than at present. 



I am sure it will be readily granted that there is 

 zoological evidence for the belief of such a connection 

 or union between the two great seas. However, it 

 may be urged that owing to the presence of an ice- 



