xvi.] ARTIODACTYLA. 299 



confluent throughout the greater part of their length, though 

 separated for a considerable distance at the lower end. The 

 distal articular surfaces, instead of being pulley-like, with 

 deep ridges and grooves, are simple, rounded, and smooth. 

 The proximal phalanges are expanded at their distal ends, 

 and the wide and depressed middle phalanges are imbedded 

 in a broad cutaneous pad, forming the sole of the foot, on 

 which the animal rests in walking, instead of on the hoofs, 

 as in other Ruminants. The ungual phalanges are very 

 small and nodular, not flattened on their inner or opposed 

 surfaces, and not completely encased in hoofs. These 

 characters are better marked in the true Camels than in the 

 Llamas. 



In the animals constituting the order CETACEA, the manus 

 has undergone a special modification, being converted into 

 a simple, flattened, oval or falciform, usually pointed flipper 

 or paddle, showing externally no signs of division into 

 separate digits, nor any traces of nails or claws. The skele- 

 ton, however, consists, as in other Mammals, of a carpus, 

 metacarpus, and either four, or more commonly five, digits, 

 the great peculiarity of which is, that the number of pha- 

 langes is not limited to three, as in all other animals of 

 the class, but may extend even to twelve or thirteen. 



In the Whalebone Wloales, a large portion of the 

 skeleton of the hand remains permanently cartilaginous, but 

 the cartilages composing the various carpal bones and pha- 

 langes are separated from each other by interposed tracts 

 of fibrous tissue, and sometimes by synovial cavities. Nodules 

 of bone are deposited in the centre of some of these 

 cartilaginous masses, and slowly reach the surface as the 

 animal attains maturity : there are commonly not more 

 than five such ossifications. The phalanges appear like 

 cylindrical or slightly flattened bony masses, with roughly 



