282 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jail. 6, 



2. There are thirty cervical vertebrae — vertebrae, that is, which 

 present facets for articulation with ribs on the lower half of their 

 centrum ; the ribs being short and compressed superiorly, or hatchet- 

 shaped*. 



3. Three times the length of the skull equals the length of the 

 anterior twenty-three cervical vertebrae ; four times the same length 

 equals the anterior twenty-eight cervical vertebrae. It follows there- 

 fore that the neck is between four and five times as long as the skull. 



4. There are about 90 vertebrae, of which 30 are cervical, 23 dor- 

 sal, 2 sacral, and 34 or 35 caudal. 



5. The humerus and the femur are as nearly as may be equal in 

 size. 



6. The vertical diameter of the centra of the anterior cervical ver- 

 tebrae is greater than the longitudinal, the proportion being at least 

 as three to two in the third cervical. In the thirtieth cervical the 

 two measurements are nearly equal, though the vertical predominates 

 a little. So far as they are visible in the transverse sections exposed 

 by fracture of the limestone slab, the articular faces of the centra 

 are nearly circular. 



7. The cervical costal pits are elliptical, about half as long verti- 

 cally as longitudinally, and from the third to the twenty-sixth inclu- 

 sive are divided lengthwise by a well-marked longitudinal depres- 

 sion ; but there is no subdivision into two distinct facets. In all 

 these vertebrae the pits look outwards and a little downwards, their 

 axes are parallel with those of the vertebrae, and they are completely 

 sessile. 



In the last three cervical vertebrae the costal pits are directed 

 more and more backwards as well as outwards, and take the form of 

 flattened facets. At the same time their anterior edges are raised up 

 by an outgrowth of the body of the vertebra. 



8. The articular facets of the anterior dorsal vertebrae are nearly 

 circular. In the anterior eight or nine dorsal vertebrae the transverse 

 processes arise partially from below the level of the upper margin of 

 the centrum. In the tenth they appear to arise completely above 

 it, their upper margins being on a level with the upper edges of the 

 posterior zygapophyses. In the eighteenth they begin again to de- 

 scend, so that in the first sacral more than half the root of the trans- 

 verse process is below the level of the superior margin of the body. 



9. The neural spines of the cervical vertebrae are inclined a little 

 backwards, and have their anterior edges bevelled, so that their apices 

 are more or less pointed. Those of the dorsal and sacral vertebrae 

 are vertical, with their anterior and posterior margins parallel and 

 their apices squarely truncated. 



10. The articular faces of the caudal vertebrae are nearly round, 

 and their centra larger vertically than longitudinally. The neural 

 spines slope backwards a little, but their anterior edges are straight 



* The neurapophysial sutures are not visible ; but as there is reason to believe 

 that the neurapophyses do not extend upon the bodies of the cervical vertebrae 

 beyond their dorsal half, the character of a cervical vertebra here used is probably 

 equivalent to that employed by Prof. Owen Cloc. cit.). 



