Class 6. Mammalia. Order 10. Getacea. 525 



mass oJ: bJvibber* (yielding spermaceti) ; strong, conical teeth, in the lower, 

 rudimentary, in tlie upper jaw. Widely distributed ; stragglers have been caught 

 several times off the coasts of Britain. The Bottle-nose Whale (Hyper- 

 oodon rostratus), with nan'ow, pointed snout, and the head much arched behind 

 this ; almost edentulous (only one larger and one smaller tooth anteriorly in 

 each half of the lower jaw ; besides this, several rudimentary teeth above and 

 below) ; in the North Atlantic, fairly abundant, e.g., off the Faroes, and one of 

 the most common Cetaceans ; stranded on British shores. The N a r w a 1 

 {Monodon monoceros) is characterised by the possession of a long, spirally- 

 twisted tusk, which sticks straight out from the mouth on the left side ; in the 

 right side of the upper jaw, there is a similar, but much smaller tooth, which 

 remains within the bone ; there are no other teeth ; f in the female, both are 

 enclosed in the jaw. As an example of an Odontocete living in fresh water, the 

 Ganges Dolphin {Platanista gangetica), which possesses long, thin jaws 

 with numerous pointed teeth, may be mentioned ; the eyes are rudimentary, and 

 have no lens ; the skeleton is in many respects peculiar. The animal, which is 

 only 2 to 3 m. long, lives in the Ganges, Indus, etc. Two allied forms in rivers of 

 South America. 



Order 11. Bruta (Edentata). 



The animals belonging to this group are peculiar in that the 

 t e e t hj when present, are imperfectly developed, and do not form 

 a continuous series ; they are devoid of enamel, are usually all 

 approximately alike, and grow from persistent pulps : incisors are 

 absent (in one of the Dasypodidffi alone, the last incisor of the upper 

 jaw is present) : there is, as a rule, no replacement. The claws are 

 generally long, curved, and very powerful. A number of fairly 

 diverse forms belong to this order ; most of them are natives of hot 

 countries. 



1. Sloths (Bradypodidse : genus Bradypus, etc.). The body is covered 

 with long coarse hair ; the head is round ; the pinnse very small ; f cylindrical 

 teeth ; fore longer than hind limbs ; three fingers (the second, third, and 

 fourth), or only two (the second and third) ; on the hind limbs there are always 

 three toes (second, third, and foui'th) ; both fingers and toes are enclosed in a 

 common skin up to the terminal phalanx, which can be opposed to the palm or 

 sole ; the claws are falciform and extremely long and powerful ; tail rudi- 

 mentary ; exclusively arboreal, feeding upon leaves ; South and Central America. 



2. The extinct Megatheria or Giant Sloths {Megatheriidse : 

 genus Megatherium, Mylodon, etc.) occupy an approximately intermediate 

 position between the foregoing and the succeeding divisions, for they resemble ■ 

 the Sloths in respect of the head and teeth, whilst the vertebral column, the limbs 

 (of which the posterior are about the same length as the anterior) and the 

 long powerful tail are more like the corresponding, parts in M3rrmecophaga. 

 They were herbivorous animals, generally of considerable size (the largest bigger 

 than the Rhinoceros), of extremely bulky structui'e, and with very massive bones ; 



* In the same region of other Odontoceti, there is a thinner or thicker layer of 

 blubber, which in, e.g., the Pilot Whale, is well developed, and gives the head its 

 arched form (Fig. 420). 



f There may be a few. rudimentary teeth in the upper jaw, posterior to the tusk, 



