THE CERVICAL VERTEBRA. 



71 



Fig. S6. 



Figure 84. — Atlas of Timceras grande, Marsh (Xo. 10-10); front view. 

 FiGL'RE 85. — The same vertebra ; back view. 

 Figure SC. — The same vertebra ; bottom view. 



a. faoe for axis; b. fare for odontoid process of a.xis; c. face for occipital coudyle of .skii 



in neural arch for spinal nerve; nc. neural canal. 



All the fii'ures are oiie-fo\irth natural size. 



The following- measurements give the j)rincipal dimensions of the 

 atlas in one specimen of iJinoccras : 



Measurements of Atlas. {D/norer-is miruhle. No. 1251.) 



m. 

 Greatest transverse diameter of atlas, . _ . .20.5 



Greatest vertical diameter of atlas, 14 2 



Transverse diameter of neural canal, .090 



Vertical diameter of neural canal, ' '. . -'. OSO 



Antero-posterior diameter of sujjerior arch, . __ .067 



Vertical diameter of superior arch, .034 



Antero-posterior diameter of inferior arch, .149 



Diameters of faces for occipital condyles, ,. .072-.052 



Distance between faces for occipital condyles, above, . . _ .080 



Distance between faces for occipital condyles, below, .058 



Diameters of f ace J^or odontoid process, . . .043-.035 



Diameters of lateral faces for axis, _ 063-.056 



Distance between lateral faces ftJr axi.s, .065 



