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59 

 PROCAMELUS 



The others pertain to P. viiniiniis and consist of three cuboids, all of the right 

 side, two naviculars, and an ecto-cuneiform. In anatomical character they 

 accord with the same bones in the living Llama. 



Astragalus. — In the collection from the bone-bed of Mixon's plantation 

 are sixteen isolated astragali, approximating in anatomical character those of 

 the living Llama, and, judging from their proportionate size, pertaining to the 

 three extinct species indicated. Five of the specimens most approaching in 

 size those of the Llama, but larger, are probably referable to P. iniiiiiniis ; two 

 are nearly complete, the others mutilated, and one of the former is represented 

 in plate xviii. fig. 7. They differ among themselves in size and slightly also 

 in other points. From the astragalus of the living Llama they differ most in 

 the rather more grooved condition of the posterior calcanean articular surface 

 and in the complete separation of this from the outer one by a conspicuous 

 irregular grooved tract. 



The measurements of the specimens in comparison with an astragalus of 

 the recent Llama are as follows : 



Astragalus. P. minimus. A. llama. 



Length externally . . 49 mm. 54 mm. 56 mm. 43 mm. 



Length internally . . 45 " 51mm. 51mm. 51 " 39 " 



Breadth of tibial trochlea . 28 " 33 " 35 " 33 " 26 " 



Breadth of distal extremity 33 " 34 " 28 " 



According to Gervais, the astragalus oi A. castelnmidii, from Tarija, South 

 America, measured 42 mm. in length, therefore considerably smaller than in 

 P. miniinus and approximating that of the recent A. llama. 



Two astragali, according with the former in anatomical character, but 

 considerably larger, and approximating in size those of the Camel, are refer- 

 able to the second associated species, the P. viedius. One of the specimens is 

 represented in plate xviii. fig. 5. They are about the size of the astragalus 

 described by Gervais and referred to A. zveddellii, from Tarija, South America. 



The measurements of the specimens in comparison with the astragalus of 

 the latter and of the Camel are as follows : 



Astragalus. 



Length externally 

 Length internally 

 Breadth of tibial trochlea 

 Breadth of distal extremity 



