SKELETON OF THE DUGONG. 



157 



adapted for bruising such substances, and tlie movements 

 of the head in grazing require the cervical vertebrae to be 

 unanchylosed ; these are, however, short, and in the ma- 

 natee but six in number. In the dugong (Fig. 26), one 

 of these herbivorous sea-mammals frequenting the Ma- 

 layan and Australian shores, the upper and lower jaws 

 are singularly bent down, and the upper jaw is armed 

 with a pair of short tusks. The bones of all these cetacea 

 are singularly massive and compact. Tliree or four of 

 the anterior thoracic ribs are joined to a sternum — the 

 rest are free. One of the vertebrae intervening between 

 the costal and caudal series has connected with it a simple 

 pelvic arch, in which the ilium and ischium may be re- 

 cognized, and ' a still more rudimental condition of such 

 arch is suspended in the inguinal muscles of the true 

 cetacea. Most of the caudal vertebrae (Fig. 26), cd^ of the 



Fig. 26. 



SKELETOX OP THE DUGONG {Halicore Australis). 



manatee and dugong, have long diapophyses, and ha3mal 

 arches (Fig. 26), h. The terminal vertebra are flattened 

 horizontally. 



The lacteal organs of the dugong are placed on the 

 breast, and the pectoral fins, in the female at least, are 

 U 



