48 



Again, the number and peculiar disposition of the incisors, and the 

 number and heavy make of the molars, point to a still nearer alliance 

 with the Ehinoceros, and possibly with the water-loying anoplo- 

 .therioids, whose canines are wanting, or are small and indistinct, and 

 whose toes are protected by hoofs. 



But the flattened crown of the head ; the position of the breathing 

 aperture, and that of the articulating process of the skull to the neck 

 vertebrae, tend strongly to the conviction that the Toxodon, although 

 from the presence of large frontal sinuses, was probably not so strictly 

 aquatic as the Deinotherium', was nevertheless highly so, and nearly 

 related to it, and to the Sirenioids ; if so, the continual recurrence to 

 the waters of the deep for subsistance would necessitate, as in the Seals, 

 the use of fin-shaped limbs. 



The skull in question measures about 2 feet 4 inches in length by 

 1 foot 4 inches in breadth, and about equals that of the Hippopotamus. 



Toxodon angxtstidens, Owen. 



Professor Owen regards the relics found at Buenos Ayres as consti- 

 tuting a distinct species, the animal of which would be but little inferior 

 in size to the preceding. 



Toxodon paeanensis, D'Orbigny. 



Is too much involved in obscurity to be considered as a reliable 

 species. 



Order 9. SIRENIA,=^ 



Manatee, Dugong, &o., &c. 



Teeth, when present, of two kinds only, incisors and molars; body 

 elongated, conical, whale-like, sparsely covered with hairs ; neck some- 

 what flexible ; fore limbs converted into flippers, in some slightly 

 unguiculated ; fingers with the normal number of joints (three) as in 

 the clawed mammals ; hind limbs wanting, the body being terminated 

 by an expanded, cartilaginous, horizontal tail ; muzzle obtuse, truncated, 

 thickly bristled ; front of both jaws and part of the palate covered with 

 a hard, corneous plate, externally tuberculated in undulating rows, the 

 substance being composed of short, vertically placed bristles, agglu- 

 tinated together by a horny matter, and bearing a considerable analogy 

 to whalebone ; nostrils separate, valvular, opening at the extremity of 

 the muzzle, and connected to the nasal aperture of the skull by 

 lengthened cartilage, and never employed as blow-holes ; ears without 



' Owen, Zoology of the Voyage of the " Beagle." 



' Sirenia, from a Bupposed resemblance of the anterior part of the body, when 

 raised out of the water, to that of a siren, or mermaid. 



