502! MANUAL OF ZOOLOGY. 



O. Capensis, which is peculiar to South Africa, and is known 

 by the Dutch colonists as the "Aardvark" or Ground-hog. 

 The animal is nocturnal in its habits, and lives upon insects. 

 The body is elongated, and the tail is long, the species attain- 

 ing a total length of four feet or more. The legs are short, the 

 anterior pair having four unguiculate toes, the posterior five. 

 The claws are strong and curved, and enable the animal to 

 construct extensive burrows. The skin is very thick, and is 

 thinly covered with bristly hairs ; and the tail is hairy. The 

 head is elongated, and the mouth small devoid of incisor 

 and canine teeth, but furnished with a number of cylindrical 



7 7 

 molars (g- g), The crowns of the molars are flat, and they 



are composed of dentine traversed by numerous dichotomising 

 pulp-cavities. The tongue is long, and is covered by a sticky 

 saliva, by the aid of which the animal catches insects. 



CHAPTER LXXVI. 

 SI RENT A AND CRT ACE A. 



ORDER IV. SIRENIA. This order comprises no other living 

 animals except the Dugongs and Manatees, which are often 

 placed with the true Cetaceans (Whales and Dolphins) in a 

 common order. There is no doubt, in fact, but that the Sirenia 

 are very closely allied to the Cetacea, and though they are to 

 be regarded as separate orders, yet they may be advantage- 

 ously considered as belonging to a single section, which has 

 been called Mutilata, from the constant absence of the hind- 

 limbs. 



The Sirenia agree with the Whales and Dolphins in their 

 complete adaptation to an aquatic mode of life (fig. 192); 

 especially in the presence of a powerful caudal fin, which differs 

 from that of Fishes in being placed horizontally and in being 

 a mere expansion of the integuments, not supported by bony 

 rays. The hind-limbs are wholly wanting, and there is no sa- 

 crum. The anterior limbs are converted into swimming-paddles 

 or " flippers." The snout is fleshy and well developed, and 

 the nostrils are placed on its upper surface, and not on the top 

 of the head, as in the Whales. Fleshy lips are present, and 

 the upper one usually carries a moustache. The skin is covered 

 with fleshy bristles. The head is not disproportionately large, 



