THE EUROPEAN SEAS. 



49 



there must be abundance of living food for them in 

 the surrounding waters. 



The mollusks of Nova Zembla, and the neigh- 

 bouring coasts of Eussian Lapland, have been made 

 known by MiddendorfF. The total number observed 

 by that eminent naturalist and Von Baer, was 

 sixty-eight species, of which forty were univalve tes- 

 tacea, and twenty-five bivalves, the remaining three 

 being naked pteropods, or nudibranchs. In this 

 number we have the minimum of species pre- 

 sented in a class by any truly marine province, 

 and the entire assemblage represents molluscan life 

 under the influence of the severest conditions. 

 Fifty of these denizens of the Icy seas are identical 

 with species found fossil in the drift beds of Great 

 Britain or the south of Sweden. Between fifty and 

 sixty range to the east coast of Arctic America, and 

 considerably more than a third of the entire num- 

 ber reach Behring's Strait, or even range into the 

 sea of Okhotsk. Among the forms which appear 

 to range completely through the Polar seas, are 

 the Natica helicoides, Natica clausa, Cancellaria 

 viridula, Purpura lapillus, Trophon scalar if or mis, 

 Fusus islandicus, Terebratula psittacea, Pecten islan- 

 dicus, Modiola modiolus, Mytilus edulis, Astarte 

 elliptica and corrugata, Saxicava rugosa, Mya trun- 

 cata, Mya arenaria, and Panopcea norvegica. How 

 strikingly does this assemblage remind us of the 

 fossil fauna of the glacial epoch \ Species that 

 have, countless ages ago, deserted, our British waters 



E 



