57 



the question of the extinction of species at periods prior to any evi- 

 dence of human existence ; it does not help us in the explanation 

 of the majority of extinctions j as of the races of aquatic inverte- 

 brata which have successively passed away. 



Within the last century academicians of St. Petersburg and 

 good naturalists have described and given figures of the bony and 

 the perishable parts, including the alimentary canal, of a large and 

 peculiar fucivorous Sirenian an amphibious animal like the Ma- 

 natee, which Cuvier classified with his herbivorous Cetacea, and 

 called iSfalforiaj after its discoverer. This animal inhabited the 

 Siberian shores and the mouths of the great rivers there disem- 

 boguing. It is now believed to be extinct, and this extinction 

 seems not to have been due to any special quest and persecution 

 by man. We may discern, in this fact, the operation of changes 

 in physical geography which have, at length, so affected the con- 

 ditions of existence of the Stelleria as to have caused its extinction. 

 Such changes had operated, at an earlier period, to the extinction 

 of the Siberian elephant and rhinoceros of the same regions and 

 latitudes. A future generation of zoologists may have to record 

 the final disappearance of the Arctic buffalo (Ovibos moschatus). 

 Fossil remains of Ovibos and Stelleria shew that they were con- 

 temporaries of Elephas primigenius and Rhinoceros tichorrhinus. 



The Great Auk (Alca impennis, L.) seems to be rapidly 

 verging to extinction. It has not been specially hunted down, 

 like the dodo and dinomis, but by degrees has become more scarce. 

 Some of the geological changes affecting circumstances favourable 

 to the well-being of the Alca impennis, have been matters of ob- 

 servation. A Mend 1 , who last year visited Iceland, informs me 

 that the last great auks, known with anything like certainty to 

 have been there seen, were two which were taken in 1844 during 

 a visit made to the high rock called 'Eldey,' or ' Meelsoekten,' 

 lying off Cape Keykianes, the S. W. point of Iceland. This is one 

 of three principal rocky islets formerly existing in that direction, 

 of which the one, specially named from this rare bird ' Geirfugla 

 Sker,' sank to the level of the surface of the sea during a volcanic 

 disturbance in or about the year 1830. Such disappearance of the 

 fit and favourable breeding-places of the Alca impennis must form 

 an important element in its decline towards extinction. The 

 numbers of the bones of Alca impennis on the shores of Iceland, 

 Greenland, and Denmark, attest the abundance of the bird in 



1 John Wolley, jun., Esq. F.Z.S. 



