306 



MAMMALIA. 



are arranged in transverse rows on the back and tail, so as to form a movable 

 dermal armour (fig. 687). The limbs are short, and with their powerful 

 scraping claws are well adapted for burrowing. Incisor teeth are absent, except 

 in Dasypus sexcinctus and in the fossil CTilamydotherium. Both jaws have 

 small cylindrical grinding teeth, the number of which varies in the different 

 forms. They inhabit South America. Dasypus noveincinctus L., tho long- 

 tailed Armadillo, with eight to ten bands ; D. gigas, with upwards of a hundred 

 teeth ; CTilamydophorm truncates, Hart, the Pichyciego, in the neighbourhood 

 of Mendoza. 



Fam. Bradypoda (Sloths). With rounded head (fig. 686) and anteriorly directed 

 eyes, with very long anterior limbs and pectoral mammae. The incisor teeth, 

 and sometimes also the canines, are absent ; there are three to four grinders in 

 each half of the jaw. The large process on the jugal, descending over the lower 

 jaw, is worthy of remark. The Sloths are exclusively arboreal ; they use the 

 curved claws at the end of the two or three closely connected digits for hanging 

 on to branches during their strong but slow movements. On the ground they 

 can only drag themselves along extremely awkwardly and helplessly. The 



FIG. 6S7. Dasypus giga*. 



body is covered with long and coarse hair,, like dry hay. They live in the 

 forests of South America. Brady pus tridactylus Cuv., A'i, or three-toed Sloth ; 

 Br. torquatus 111., Cliolapus didactylus HI., Unau, or two-toed Sloth. 



Order 4. CETACEA.* 



Aquatic Mammalia with spindle-shaped body which is not covered 

 with hair ; with fin-like front limbs and horizontal caudal fin. The 

 posterior limbs are absent. 



The Whales repeat the piscine type in the form of their body and 

 in the articulation of their skeleton (Fig. 688). By their whole 

 organisation they are true Mammals with warm blood and pulmonary 

 respiration, and they are most nearly allied to the Ungulates, which 

 they approach through the Sirenia. Some species attain such a huge 



* D. F. Eschricht, " Zoologisch-anatomisch-physiologische Untersuchungen 

 iiber die nordischen Walthiere," Leipzig, 1849. 



D. F. Eschricht og J.Reinhardt. " Om Nordhvalen," Kjobenhavn, 1861. 



