156 SKELETON OF THE DUGONG. 



iilria, 54, is produced upwards into an olecranon. With 

 all those marks, however, of adhesion to the mammalian 

 type of forearm, the outward aspect of the limb is as 

 simple as is that of the fish's fin ; it moves, as by one 

 joint, upon the trunk, and is restricted to the functions of 

 a pectoral fin. 



In the huge skull of the whale, the broad vertical oc- 

 ciput may be noticed, by which the head is connected, 

 through the medium of a short, consolidated neck, with 

 the trunk ; the whole cranium seems to have been com- 

 pressed above, from before backwards, so that the small 

 nasal bones, 15, articulating with the short and very broad 

 frontals, form the highest part of the skull. The long 

 maxillaries, 21, and premaxillaries, 22, extend backwards 

 and upwards, to articulate with the nasals, and complete 

 with them the bony entry to the air-passages, situated so 

 favorably at the summit of the cranium. The nostrils, 

 formed by the soft parts guarding that entry, are called 

 *' blow-holes ;" they are double in the whales — single in 

 the smaller cetacea. In the whales, the "baleen," or 

 "whalebone" plates are attached to the palatal surface 

 of the maxillary and premaxillary bones; the expanded 

 toothless mandible supports an enormous imder lip, 

 which covers the whalebone plates when the mouth is 

 shut. The skeleton of the great finner whale {Bake- 

 noptera hoops)^ from which the foreshortened view (Cat 

 25) is taken, was ninety-six feet in length; the relative 

 dimensions of man is given by the outlines of the skele- 

 ton at its side. ISTo known extinct animal of any class 

 equalled this living Leviathan in bulk. 



There are a few whalelikc mammals, equally devoid of 

 rudiments of hinder limbs, which obtain their sustenance 

 from sea-weeds or seaside herbage. They have teeth 



