142 COUES ON THE OSTEOLOGY 



styliform processes on the third vertebra reach quite to the transverse processes of the next 

 succeeding, and, by keeping pace with the lengthening of the vertebra? themselves, are 

 longest absolutely on the eighth and ninth vertebras. They now, however, rapidly shorten, 

 and lose their very peculiar features, until on the last cervical vertebra they are merely 

 little pointed projections from the posterior aspect of the transverse processes. This fact 

 of their rapid absorption towards the thorax renders the determination of the first true 

 dorsal rib perfectly easy. These styliform processes are firmly anchylosed with the 

 transverse processes and bodies of the vertebra to which they appertain, but have no 

 connection, other than ligamentous, with the next succeeding one. 



The superior spinous processes are well developed on the anterior vertebra?, as promi- 

 nent crests or keels, running the whole length of the surfaces of the bodies ; so much 

 laterally compressed as to be thin laminae of bone rather than " spinous processes." 

 Their shape on the third and fourth vertebrae is not unlike that of the keel of the sternum. 

 They gradually decrease in size as they proceed backwards ; until, on the ninth and tenth 

 vertebrae, they amount to little more than slight compressed tubercles. These enlarge 

 again on the eleventh and twelfth, and on the thirteenth have assumed the general 

 features of those on the dorsal vertebrae. Between the dorsal surfaces of any two con- 

 tiguous vertebra? there is the ordinary aperture, closed only ligamentously, leading into 

 the spinal canal. 



The inferior spinous processes have the same general characters as the superior, — i. e., 

 they are found well developed at both extremities of the neck, but disappear in the central 

 portion. Thus the third vertebra has a very large, well-developed process, whose base 

 occupies the whole length of the body of the vertebra. This is much smaller on the 

 fourth, is scarcely appreciable on the fifth, and is totally wanting on the successive ones 

 to the eleventh. On this one, however, a spinous process reappears abruptly, being 

 larger than any of the anterior ones, and is especially noticeable for its great pro- 

 jection forwards and downwards, and its exceeding thinness. The twelfth and thirteenth 

 processes are successively smaller than this, but partake of all its general characters of 

 shape. 



The axis is chiefly noticeable for the great development of its ventral and dorsal spines, 

 the former of which extends far downwards as a thin compressed lamella of bone, larger 

 than the ventral spine of any vertebra except the eleventh. Nearly all of the body of 

 the vertebra seems to be really comprised in this spine ; and the facet for the articulation 

 of the body of the third vertebra is situate on its posterior edge just at its base. The 

 roof of the spinal canal is quite flat, and from its median line rises the dorsal spinous 

 process, not really so large as the ventral, but still quite stout and prominent, and 

 terminating in a thickened tuberculous apex. The flat roof of the spinal canal spreads 

 out posteriorly into the transverse processes, which bear their articulating facets directly • 

 upon their under surface. The oblique processes, for articulation with the atlas, have their 

 facets presenting directly outwards ; and these are received within the ring of the atlas. 

 The large facet which articulates with the body of the atlas is regularly oval, and quite 

 deeply concave ; the odontoid process well developed, convex in every direction upon its 

 articulating aspects, flat on the side which presents toward the spinal canal. 



The ring of the atlas is large, suboval in shape, its long diameter transverse. Pos- 

 teriorly, it sends down on either side its slight transverse process, which overlies the 

 anterior extremity of the axis. The fossa for the reception of the single occipital condyle 



