83 



lhan any oilier vertebrae. In such, the centrum is less compressed, though 

 with concave sides, and with a section rather quadrate. 



The cervical vertebrae, from the sixty-sixth to the thirty-ninth, are all 

 longer than the dorsals ; they commence four inches in length, increase to 

 five, and diminish to four again. 



Measurements. 



Inches. Lino. 



Leugth of sixty-third cervical 4 9. 2 



Depth of the articular face of the centrum 3 8. 



Width of the articular face of the centrum 3 10. 2 



Total elevation of the ninth cervical 2 9. 



Auterior posterior diameter of the third cervical 2 2. 



Transverse diameter of the third cervical 2 11. 



Length of the head of rib r 1 9. 7 



Width of the head of rib 1 3. 



Width of the shaft of rib 1 10.5 



Many of the ribs preserved have been pressed upon the vertebrae and 

 crushed. 



The first dorsal is that vertebra which first presents a distinct articula- 

 tion for a rib. The diapophyses are never much elevated above the cen- 

 trum, and are longest on the thirteenth (inserting seven supposed to be lost). 

 Their form is stout and much depressed, and distally expanded. They dimin- 

 ish gradually, and, on the third, are represented by a longitudinal angulation; 

 the superior angle is first distinct on the first, and bounds the articular sur- 

 face last on the third. They give the transverse section of the posterior cer- 

 vicals a pentagonal form ; that of the anterior dorsals is nearly circular. The 

 latter are strongly constricted medially, and the articular faces are slightly 

 concave. The external surface near the included angle is coarsely ridged, in 

 conformity with coarse cellular texture of the spongy bone. The venous 

 foramina gradually become more widely separated, approaching each other 

 again on the posterior cervicals. On the dorsals, they occupy the bottom of a 

 more or less pronounced concavity. These concavities, on the posterior dor- 

 sals, are bounded externally by a strong obtuse longitudinal angulation, giving 

 a quadrate outline to the section of the centrum in this part of the series. 



The posterior cervicals are not readily distinguished from the anterior 

 dorsals. In the latter, the ribs appear to be present, of reduced length, judg- 

 ing from the smaller size of the remaining heads. The articular pits continue 

 to descend till their lower marginal ridge is the inferior lateral angle of the 

 vertebra. On such vertebrae, the inferior surface is flat. 



