548 



MR. E. I. POCOCK ON TUB EXTERNAL 



sole is not very tliick at the heel, but it thickens towards the 

 hoofs, forming a strong junction at this point between the two 

 digits. The inner surface of each digit between this junction and 

 the hoof is naked. (Text-figs. 44, 45.) 



l^he Penis. 



Athough the penis in the OamelidjB has been previously 

 described, this organ in the Mammalia generally is so important 

 from the systematic standpoint that I venture to dx\aw attention 

 to the profound differences it exhibits in this family from that of 

 the rest of the Artiodactyla. In the latter the glans is alwavs 



Text-fiffure 45, 



A, B. Lower view of fore and hind foot of 0. dromedarius, 

 C. Section of foot of the same. 



soft and flexible. Considering its length, it seems remarkable 

 that in no case has an os penis or baculum been developed. In 

 the Camelidse also there is no baculum, but the tip of the glans 

 instead of being soft is rigid, hard, and apparently cartilaginous. 

 The apex, moreover, is bent sharply to the left, like a stout hook, 

 underlying and apparently acting as a guard to the slender, 

 straight, forwardly dii'ected process, at the tip of which the genito- 

 urinary orifice opens. 



In the Alpaca and in Lama huanacus the hook is simple and 



