AND VARIOUS OTHER BONES OF THE MASTODON. 43 



The second cervical vertebra (see Plate I., Fig. 3) exhibits in its processus 

 dentatus a broad regular cone, elevated one and a half inches, and whose sum- 

 mit reaches to the level of the internal margin of the superior oblique processes 

 of the first vertebra. Its spinous process is more robust than in the Elephant, 

 and comes in contact with that of the first by a broad well-marked surface. 

 This vertebra in the specimen before us, is anchylosed with the third in almost 

 the whole length of the long bridge between the oblique processes inclusive. 

 Its transverse diameter in the body is seven and a half inches — and the antero- 

 posterior diameter, from the front of the body to the tip of the spinous process, 

 measures ten inches. 



The spinous process of the third, fourth, fifth, and sixth vertebrae is very 

 small and short. These vertebrae are nearly circular, (see Plate II. Fig. 2) and 

 measure nearly six inches in diameter, and nearly two and a half inches in 

 thickness, in their bodies. They shoot up from the anterior root of the trans- 

 verse process, a conical spine, sixteen or eighteen inches in height, which sets 

 close against the body of the vertebra above, and assists materially in prevent- 

 ing its dislocation. A vertebra of this description, when inverted, resembles a 

 table standing on four legs; the two front legs being these conical spines, and 

 the two hind ones the upper oblique processes. There is an arrangement in 

 the Elephant tending to this, but by no means so finished, as the conical spine is 

 much shorter, and does not touch, by a considerable space, the vertebra above it. 



The first six thoracic vertebrae have very long spinous processes ; that of the 

 foremost measures twelve inches, of the second thirteen and a half, and of the 

 third about the same; they then diminish in length. 



The lumbar vertebrae, sacrunij and the caudal vertebrae, are similar to those 

 of the Elephant. 



The sacro iliac junction is anchylosed. 



PELVIS. 



Its conformation presents the same type as in the Elephant, but the measure- 

 ments are much more considerable. The innominata join also from the top 

 of the pubes to the anterior part of the tuber of ischia by a synchondrosis ar- 

 ticulation ; there is, therefore, no pubic arch as in the human subject. 



The distance from the anterior superior spinous process to the centre of the 

 sacrum is two feet nine inches. From the same process to the posterior ex- 

 tremity of the symphysis of ischia measures three feet two inches. 



