200 LEA'S DESCRIPTION OF A FOSSIL SAURIAN 



One of the specimens (pi. 19, fig. 2,) presents the posterior face of a vertebra with 

 the centrum broken off. The spinous process, the superior oblique process, and the 

 left transverse process, are all nearly perfect, but somewhat bruised. The right 

 transverse process is probably still in the mass of the stone, from whence I have not 

 attempted to remove it. The canal is much broken round the edges, and it is filled 

 up with the very hard mass of the surrounding rock. 



The length of this spinous process is 2.1 inches. 



The distance across the oblique processes is 2.9 inches. 



The length of the transverse process is 2 inches ; its width is half an inch. 



The distance from the centrum to the apex of the spinous process is 2.2 inches. 



In the specimen pi. 17, fig. 1, there are parts of two vertebrae, with the spinous 

 process attached, and, although these processes are much broken, they are still in 

 place. The two vertebrae are nearly in their natural positions. The length of these 

 spinous processes is about 2| inches; antero-posterior diameter 1.2 inches; transverse 

 diameter seven-twentieths of an inch ; the surface of the terminal extremities 1.5 by 

 1 inch, in their greatest diameters. 



A vertical view of a centrum is given on pi. 17, fig. 2. It is somewhat fractured, 

 and partly concealed in the mass of the rock. It presents a most remarkable com- 

 pressed central portion, being exceedingly contracted laterally, while the terminal 

 articular portions are nearly rounded. Its length is 2.1 inches; its vertical diameter 

 in the centre one inch, and its transverse diameter .3 of an inch. On pi. 18, fig. 2, 

 another centrum is represented, which is rather shorter, and not quite so much laterally 

 compressed ; but it presents the same remarkable hour-glass form of the vertebra of 

 this animal. Fig. 3 presents a view of the terminal articular cavity of a centrum, 

 somewhat elliptical, a portion of the border being fractured. The depression is gentle 

 towards the centre. Its greater diameter is 1.6 inches. Fig. 4 represents a 

 fractured portion of a centrum, which has a slight groove on its superior surface, 

 which may be the impression of the undulating canal. Fig. 5 consists of three 

 somewhat mutilated centri, less compressed' than those of the other portions of the 

 column. 



Ribs. Plate 19, fig. 1 and 1 a; natural size. 



The mutilated state of the specimens permits but a slender description and 

 representation of these bones. They consist of a few fractured pieces, and one 

 proximal extremity, the head being broken oflT, as well as a small portion of the neck ; 

 but the tubercle is entire. The anterior and posterior faces of this portion are 

 represented at fig. 1 and 1 a, of the natural size. 



