62 



THORACIC AND LUMBAR VERTEBRA. [CHAP. 



In Brady pus a small (anapophysial) process projects 

 backwards from the hinder edge of the transverse process 

 of each lumbar vertebra, having on its inner surface a facet, 

 which articulates with a corresponding facet on the anterior 

 edge of the arch of the succeeding vertebra, below the 

 ordinary zygapophysis. 



In Megatherium^ Myrmecophaga^ Cydoturus, and Dasypus 

 (in fact, all the remaining American Edentates), a disposition 

 thus slightly indicated in the Sloths, is carried out to a great 



cc 



FIG. 22. Side view of twelfth and thirteenth thoracic vertebrae of Great Anteater 

 (Myrmecophagajubata), \. in metapophysis ; tc facet for articulation of tubercle 

 of rib ; cc ditto for capitulum of rib ; az anterior zygapophysis ; az l additional 

 anterior articular facet ; pz posterior zygapophysis ; pz 1 and pz z additional pos- 

 terior articular facets. 



extent, and results in a very complex and altogether peculiar 

 method of articulation between the vertebrae. 



It will be most convenient to describe it from one species, 

 the Great Anteater (Myrmecophagajubata), but it is the same 

 in principle in all the above-named genera. 



The anterior thoracic vertebras articulate in a perfectly 

 normal manner by large anterior and posterior zygapophyses. 

 These retain the horizontal position of their facets through- 

 out. On the eleventh dorsal vertebra, the upper surface of 

 the backward projecting process which bears the posterior 



