222 SI REN I A 



very existence would have been unknown to science but for the 

 interesting account of its anatomy and habits left by Steller, and 

 the few more or less imperfect skeletons which have recently re- 

 warded the researches carried on in the frozen soil of the islands 

 around which it dwelt. There is no evidence at present of its 

 having inhabited any other coasts than those of the islands just 

 named, although it can hardly be supposed that its range was 

 always so restricted. When first discovered it was extremely 

 numerous in the shallow bays round Behring Island, finding 

 abundant nutriment in the large laminarise growing in the sea. 

 Its extirpation is entirely due to the Russian hunters and traders 

 who followed upon the track of the explorers, and, upon Steller's 

 suggestion, lived upon the flesh of the great Sea-cows. Its 

 restricted distribution, large size, inactive habits, fearlessness of 

 man, and even its affectionate disposition towards its own kind 

 when wounded or in distress, all contributed to accelerate its final 

 extinction. 



According to Steller's account, the Rhytina had a skin of a dark 

 brown colour, sometimes spotted or streaked with white. The fore 

 limb was covered with short brush-like hairs. 



EXTINCT SIRENIANS. 



Halitherium. 1 The Miocene and early Pliocene seas of Europe 

 abounded in Sirenians, to which the generic name of Halitherium 

 Avas given by Kaup, but which have also received other names. 

 They had large tusk-like incisors in the upper jaw, as in the 

 existing Dugongs, though not so greatly developed. Their molar 

 teeth were -f- or -|, anteriorly simple and single-rooted, posteriorly 

 those above with three and those below with two roots, and with 

 enamelled and tuberculated or ridged crowns, in all which respects 

 they more resemble those of the Manatee than of the Dugong. 

 The anterior molars were deciduous ; and there is evidence of the 

 presence of milk-teeth. Germs of inferior incisors were also 

 present. Some species at least had nasal bones, short, broad, 

 but normal in position, whereas in all the existing genera these 

 bones are quite rudimentary. Another and still more important 

 evidence of conformity to the general mammalian type is the 

 better development of the pelvic bone, and the presence of a small 

 styliform femur articulated to the acetabulum, although no traces 

 of any other part of the limb have been discovered. These ancient 

 Sirenians, which may be regarded as representing a distinct family 

 Halitheriidce were thus, in dental, cranial, and other osteological 

 characters, less specialised than are either of the existing species, 



1 Kaup, Ncues Jahrbuch, 1838, pp. 319 and 536. 



