EXTINCTION OF SPECIES. 437 



stances favourable to the well-being of the A lea impennis, 

 have been matters of observation. An estimable naturalist, 

 the late John Wolley, Esq., who visited Iceland in 1858, in- 

 formed me that the last great auks known with anything 

 like certainty to have been seen living, were two which were 

 taken in 1844? during a visit made to the high rock, called 

 "Elcley," or " Meelsoekten," lying off Cape Eeykianes, 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 disturb- 

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

 fit and favourable breeding-places of the A lea 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 former times. 



Within the last century, academicians of Petersburg and 

 good naturalists described and gave figures of the bony and 

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

 and peculiar fucivorous Sirenian — an amphibious animal like 

 the Manatee, which Cuvier classified with his herbivorous 

 Cetacea, and called Stellerns, after its discoverer. This animal 

 inhabited the Siberian shores and the mouths of the great 

 rivers there disemboguing. It is now believed to be extinct, 

 and this extinction appears 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 conditions 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 disappear- 

 ance of the Arctic buffalo (Ovibos moschatus). Eemains of 



