28 THE ASIATIC FUR-SEAL ISLANDS. 



Lack of time and space prevents more than the -briefest possible r^sum^ of the 

 subject in the present connection; a more ■exhaustive treatise would make a book iu 

 itself. There is abundant evidence in the material at hand to show that the islands 

 during the period previous to which they received their present fauna and flora were 

 totally covered by the sea, and that since that time they have not been connected with 

 the mainland on either side. From this it follows that the animals and plants are not 

 truly indigenous, though I have no doubt that many of the numerous species described 

 as new from these islands are really peculiar, and not found elsewhere; but in that case 

 their origin on the islands is undoubtedly due to comparatively recent isolation. The 

 sporadic character of the fauna and flora as shown in the great number of genera 

 in proportion to the species, as well as the absence of many forms which, from their 

 general distribution, would be expected to occur, is clearly indicative of the accidental 

 immigration of the component species. They evidently immigrated, especially and 

 more regularly from the west, from Asia, by means of prevailing winds — currents and 

 driftwood carried by these — and more seldom from the east, from America. That such 

 inhabitants as are more independent of the above agencies likewise show nearer 

 relationship to the Asiatic fauna is partly due to the shorter distance and partly to the 

 well-known effort of the Asiatic fauna to extend beyond its own limits. 



As might be expected from their location, the islands are chiefly palaearctic in 

 their bio-geographical relations, with a fair sprinkling of circumpolar, American, and 

 North Pacific forms. The marine fauna and flora partake more particularly of this 

 latter character, and it is probable that Dr. W. H. Dall's conclusions, derived from a 

 study of the moUusks, applies to most of the other marine animals, viz: 



Tho fauna of Commander Islands, as far as known, is intimately related to tlie general Arctic 

 fauna and especially to the Aleutian fauna, somewhat less so to the Kamchatka fauna, but presents in 

 itself nothing distinctive. While the faunal aspect of the mollusca is horeal, there is a number greater 

 than might be expected of species common to Japan and California. 



To this statement he afterwards added the note: 



The connection with Japan is rather that the northern forms extend southward into Japan than 

 that any characteristic Japanese forms extend north. (Proc. U. S. Nat. Mus., ix, 1886, p. 219. ■> 



MAMMALS. 



The chief zoological interest centers in the four marine mammals revealed to the 

 scientific world in Steller's famous treatise "DeBestiisMarinis" (Xovi Comm. Ac.Sc. 

 Imp. Petrop., ii, 1751, pp. 289-398, pis. xiv-xvi); which must always remain a 

 monument to the learning and industry of its author. In this he described for the 

 first time the sea cow, the sea lion, the fur-seal, and the sea otter. 



Of these, the sea cow (Eydrodamalis gigas, also known as Bytina gigas or stelleri) 

 possesses greatest interest, on account of its early extermination by man, which took 

 place in 1768, twenty-seven years after its discovery. The sea cow was an herbivorous 

 animal, anteriorly shaped somewhat like a seal, but with a large caudal fin like that of 

 a whale or fish, but no hind legs, and belonging to the mammalian order of Sirenia, the 

 few living relations of which, the manatee and dugong, now only inhabit the tropical 

 waters of both hemispheres. There is no indisputable evidence of its having ever 

 inhabited other coasts than those of the Commander Islands, as the find of a rib on 

 Attn Island does not necessarily prove that the animal once lived there, though that 

 is not improbable. The history of this animal, imperfectly known as it is, fills 



