AXIAL SKELETON Of THE OSTfilCH. 429 



The Fobty-eighth Vertebra. 

 This vertebra is like the last, except that there are no subcentral excavations. The 

 diapophyses extend less dorsad ; and the panqjophysial projection is smaller on each side. 



The Forty-ninth Vertebra. 



This vertebra differs from the preceding chiefly in the sudden reappearance of a 

 parapophysis of considerable size. It is, however, continuous with the diapophyses, 

 the two appearing as a transverse process, which projects outwards and slightly post- 

 axiad from the postaxial part of the side of the centrum, and expands dorso-ventrally 

 towards its distal end (fig. G5, d, p). 



THE FOETY-NINTH, ob THIRD CAUDAL TERTEBKA (natural size). 



Pig. 65. 



ns 



rig. 65, preaxial aspect. Letters as before, except that t denotes the " transverse process," which probably 

 contains both a diapophysial {d), and a parapophysial {p) element. 



Its free outer margin is dorso-ventrally concave, the prominence at the dorsal side of 

 the concavity representing the rounded end of the diapophysis, while the sometimes 

 less marked prominence on the ventral side of the concavity represents the rounded end 

 of the parapophysis. The preaxial surface of the transverse process is excavated and 

 dorso-ventrally concave. 



The Fiftieth Vertebra. 



The fiftieth vertebra is slightly smaller than the forty-ninth, which it greatly resembles, 

 except that the parapophysial (ventral) extremity of the transverse process is decidedly 

 more produced than the diapophysial one. 



The neural canal is also smaller, and the lateral summits of the laterally bifurcating 

 neural spine more divergent. 



The Fifty-first Vertebra. 

 Here we find an intensification of the differences noticed in describing the fiftieth 

 vertebra ; and the outer margin of the centrum also more nearly approaches a circle. 

 The preaxial surface of the centrum is decidedly concave. 



