26 DESCRIPTION OF THE SKELETON. 



transverse processes, is seventeen inches, nearly a foot and a half in length. 

 While each of these processes is in this about six inches in length, that 

 of the last dorsal is only three inches. 



The bodies of these lumbar vertebra? have a more oval form than those 

 of the dorsal generally. Like that of the posterior dorsal, they are much 

 excavated on the lower surface. On the whole, these bones are more 

 massive than the dorsal ; but the difference in this respect is not so great 

 as it is in man, in quadrumana, and in carnivora. 

 os Os Sacrum (Plate XXIV.). — This bone is slightly excavated inferiorly. 



Sacrum. 



It consists of five pieces, presents four pairs of holes, and a pair of grooves 

 below and behind. The excavation is of an oblong form, extending from 

 the anterior or larger to the posterior or smaller extremity. The hollow 

 of the sacrum, as seen in man, does not exist. The sides or edges are very 

 thick, and are co-ossified with the ossa innominata, The inferior face is 

 twenty inches long ; the upper articulation measures seven inches across ; 

 on each side of it is the iliac portion of this bone, four inches in extent. 



The posterior face of the os sacrum is rough, from its numerous pro- 

 cesses. Superiorly and anteriorly are the two long transverse processes of 

 the first bone; below these are three other pairs of transverse processes. 

 The spinous processes are five, the first and last of which are the most 

 prominent. There are five pairs of holes on this face. The inferior ex- 

 tremity is nine inches across. The spinal canal is much flattened, and 

 measures three inches across. 

 caudal Caudal Vertebrae (Plate XXII. Figs. 6, 7, 8). — A number of these 



were not found with the skeleton, having no doubt been decomposed ; but 

 those which exist appear to be of three classes : the first having spinous 

 and transverse processes; the second having transverse with indistinct 



