VERTEBRAE AND RIBS 



175 



varies ; two to four may be thus united. The additional 

 articular facets upon the dorsal vertebrae have been already 

 commented upon as a point of important likeness to other 

 American Edentates. The dorsal vertebrae are commonly eleven 

 in number, the lumbar being three. But in Priodon the numbers 

 are twelve and two respectively. There are traces to be observed 

 of the double-headed attachment of the ribs to the sternum. The 



FIG. 100. Bones of the right 

 maims of the Hairy Armadillo. 

 Dasypus villosus. x . c, 

 Cuneiform ; I, lunar ; m, mag- 

 num ; p, pisiform ; R, radius ; 

 s, scaphoid ; id, trapezoid ; tm, 

 trapezium ; , unciform ; U, 

 ulna; I - V, digits. (From 

 Flower's Osteology.) 



FIG. 101. Bones of the manus of 

 the Great Armadillo. Priodon 

 giganteus. x . a. An acces- 

 sory carpal ossicle in front of 

 the pisiform, which is not seen 

 in the figure. Other letters as 

 in Fig. 100. (From Flower's 

 Osteology. .) 



shoulder girdle of the Armadillos is somewhat diverse in form in 

 different genera ; the acromion is always large, and is remark- 

 able in Priodon for the fact that the humerus also articulates 

 with it, its extremity being recurved, and forming a socket for 

 this purpose. As in some other Edentates there is a second 

 spine on the scapula behind the first. The clavicle is strong. 

 There is some variation in the form of the manus. It is five- 

 fingered in Dasypus ; in TolypeuUs the first digit has vanished ; 

 on the other hand, in Priodon, the fifth has* become rudimentary 



