S72 THE ANATOMY OF VERTEBRATED ANIMALS. 



ing vertebras this increases in length and strength, till in the 

 lumbar region it becomes as long as the spinous process. In 

 the last lumbar, it is short, and in the sacrum it is obsolete, 

 but it is traceable through the series of the anterior caudal 

 vertebrte. Accessory processes, or (mapophyses, are observa- 

 ble in the last dorsal and four or five anterior lumbar vertebrae. 

 The transverse processes of the lumbar vertebrae are exceed- 

 ingly long, and that of the first lumbar is bifurcated at its ex- 

 tremit}'. These transverse processes give attachment above, 

 to the sacro-lumbalis, and below, to the psoas major, both 

 which muscles are very large ; while the heads of the longis- 

 simus dorsi are attached to the long metapophyses. The great 

 mass of these extensor and flexor muscles of the spine, and 

 the leverage afforded by the mode of their attachment to the 

 long processes of the vertebrae, would seem to be related to 

 the leaping and scratching movements of the Rabbit. Strong 

 median processes are developed from the ventral faces of the 

 centra of the three anterior lumbar vertebrae ; these give attach- 

 ment to the crura of the diaphragm. 



The tubercles of the second to the eighth ribs inclusively 

 are prolonged into spiniform processes, which give attachment 

 to the tendons of the longissinnis dorsi. There are five ster- 

 nebras and a long xiphoid process. The manubrium is long, 

 narrow, deep, and keeled inferiorly. 



In the skull, the great supra-orbital processes of the frontal 

 are to be noted. The presphenoid is high and greatly com- 

 pressed from side to side, so as to form a thin septum between 

 the orbits, and the optic foramina run into one, as in some 

 Seals. The tympanic and the periotic are anchylosed together, 

 but remain distinct from the adjacent bones, and are merely 

 held in position by abutting against the basi-sphenoid on the 

 inner side and bj' the post-tympanic hook of the squamosal on 

 the outside. The tympanic is prolonged upward and outward 

 into a tubular meatus. The glenoid cavity is elongated from 

 before backward. The suture between the jugal and the 

 maxillary becomes obliterated, and there is no orbital process 

 given off from the zygoma. A considerable extent of the 

 outer wall of the maxilla remains incompletely ossified. The 

 premaxilla is extremely large and trifurcated. 



The ascending portion of the ramus of the mandible is long, 

 and the coronoid process well developed. The long axis of 

 the condyle is antero-posterior, and the angular process has a 

 slight inward projection. In the palate, the prepalatine, oi 

 incisive foramina are enormous ; and partly in consequence of 



