ORDER OF EDENTATA. SLOTHS. 93 



enveloped in stout nails upon which they walk with difficulty. 

 Their common distinctive character is the wanting of teeth in the 

 anterior part of the jaws, that is, the incisor teeth. (Plate 4. fig. 3.) 

 Sometimes the canine and molar teeth are also wanting, so that 

 the animal is then entirely edentate. This order is divided into 

 three families which may be recognised by the characters enu- 

 merated in the following table : 



(Families.) 



{The face very short. TARDIGRADA. 

 The muzzle long 1 , ) ORDINARY 

 and pointed. { EDENTATA. 



[ Provided with a cloaca. (1.) .... MONOTREMATA. 



(1.) NOTE. That is to say, having the rectum and duct for the passage of 

 the urine opening into a common cavity, called cloaca which has a single 

 outlet, as is the case in birds and reptiles. 



FAMILY OF TARDIGRADA, OR SLOTHS. 



2. The SLOTHS, Bradypus, bear some resemblance to de- 

 formed and stupified monkeys, and they have in their whole being 

 something so disproportioned and strange, that at first sight they 

 might be taken as the product of some fantastic freak of nature ; 

 but when these anomalies are closely studied, we find they have 

 their use, and that they all tend, however grotesque they seem, to 

 adapt the organs of the animal to the purposes for which its kind 

 of life has designed them. 



3. When on the ground, nothing is more awkward, more un- 

 graceful and powerless than the sloths. Their short, stout body 

 is borne on extremities so unequal in length, that, in order to 

 walk, the animal is obliged to tread on its elbows ; the pelvis is 

 broad, and the thighs are directed so much outwards, that they 

 cannot bring the knees together ; at the same time their hind feet 

 are articulated so obliquely upon the legs that they only touch the 

 ground by their external edge ; and the toes, joined together by 

 the skin, do not show except by their enormous hooked nails, 

 which are flexed when at rest, and they possess so little move- 

 ability that at a certain age the first phalanges become soldered to 

 the bones of the metacarpus and metatarsus. The sitting and 

 vertical position is least inconvenient to them, but their head being 

 in a line with the axis of the body, their mouth then looks up- 

 wards, rendering it very difficult for them to graze upon the 

 ground ; add to this that their flexor muscles are much more 



2. Are Sloths really misshapen and illy formed animals ? 

 3. What are the general peculiarities of the conformation of the Sloths? 

 How do they feed ? 



