SKELETON OF BRUTA 



399 



perforated by the vertebral artery anteriorly, and by the cervical 

 nerve posteriorly. The spines of the cervical vertebroe are mo- 

 derately and equably developed. The pleurapophysial part of the 

 transverse process of the eighth cervical, fig. 265, «, pi, is more 

 extended antero-posteriorly than in the preceding cervicals, and 

 long remains free. The pleurapophysis of the ninth cer\dcal, 

 ib. b, 2^1, retains its freedom, and is more extended in the direction 

 of its length, but is very short as compared with the homologous 

 part, pi, of the following vertebra. The slender neck and head 

 of this little rib, joining the fore part of its centrum, occasions the 

 perforated character, as in the antecedent cervical vertebra. A 

 short metapophysis is developed from the fore part of the diapo- 

 physis of the penultimate dorsal vertebra, increases in size in the 



264 



Three-toed Sloth. 



last dorsal, and ascends upon the base of the prozygapophysis of 

 the third lumbar vertebra. The anapophysis is also developed from 

 the last dorsal and from the three lumbar vertebras ; it is short, 

 with an articular surface applied to the outer side of the pro- 

 zygapophysis of the succeeding vertebra. The spinous processes 

 gradually subside in the posterior dorsals, fig. 264, d, and become 

 obsolete in the lumbar vertebras, L. The first pair of dorsal ribs, 

 pi, h, is anchylosed to the manubrium, s: nine pairs directly 

 articulate with the sternum, which consists of eight bones ; these 

 are compressed, and progressively increase in depth ; the hinder 

 ones are divided into a larger posterior and a smaller anterior 

 part, between which are four articular facets on each side for 

 the bifurcated extremities of two of the ossified cartilaoces. There 



