BKADVriD.E.- 



-JIAMJIALIA.- 



-Bkadypid-b. 



153 



very nearly twice as long as the hinder extremities, 

 and in tliis feature we are inevitably reminded of a 

 siniUar arrangement in the Hmbs of certain quadi-u- 

 mana whose habits are in some respects analogous to 

 tliose of tlie family under consideration. On closer 

 inspection of the hands, it wiU be noticed that the 

 bones of the carpus and metacarpus are short and 

 nnkylosed together, whilst the terminal digits are 

 long, and furnished witli immense hooked claws. 

 These prehensile talons are closely curved towards the 

 palm while not in use, or in a state of rest ; but wlien 

 tlie animal requires to gi'asp a fresh brancli, they are 

 forcibly extended by muscular conti'action, assmning 

 a position like that given in the raised arm of the 

 accompanjdng representation, above referred to. The 

 land feet are similarly constructed, and a glance at 

 their position, with the soles directed obliquely inwards, 

 is suflicicnt to show how imnatural it is to represent a 

 Sloth walking all-fours on a plain level surface. In the 

 older natm-al history collections of the United Ivingdom, 

 notliing is more common than to observe tlie errors 

 into which taxidemiists have fallen in mounting and 

 displaying tlie stuffed skins of Sloths ; and we could 

 still pouit to fine collections where tlie tardigrade 

 edentates may be seen sprawlmg on tlie floor in the 

 most approved style, with their backs toward the sky ! 

 Having personally inspected, with care, the principal 

 museums of natural history in London, Edinburgh, 

 Glasgow, and Dublin, we have no hesitation in saying 

 that, if any one \vislied to see the way in which Sloths 

 ought to be stuffed, tliey would do well to take a 

 glance at the specimens preserved in the museum of 

 Trinity College, Dublin — and they are not the only 

 evidences of taxidermal skUl to be seen in the Irish 

 capital. But, to return to our skeleton, and the 

 figure reduced from that given in Cuvier's celebrated 

 "Ossemens Fossiles" — let us next examuie the head 

 (fig. 5'2). Here wo have a striking contrast when 

 compared with tlie attenuated crania of the ant-eaters. 



Fig. 52. 



Skull of the Sloth. 



Tlie Sloth's head is short, rounded, flat, and truncated 

 at the muzzle ; the jaws are generally furnished \vith 

 eighteen molar teeth — the anterior pair, above and 

 below, having been regarded by Cuvier as meisors; 

 the young individual carries twenty molars. In the 

 constiiiction of the bones of the trank, and especially of 

 the pelvis, we notice otlier interesting adaptations to the 

 pecidiar habits of these creatiu'es ; but among these we 

 have only space to mention the remarkable elongation 

 Vol. I. 



of tlie neck. This cervical extension was at one time 

 supposed to be due to the presence of nme true neck- 

 vertebrse ; but some years since. Professor Bell satis- 

 factorily demonstrated, from prepared skeletons in his 

 own collection, that the so-called eighth and nuith 

 cervical verctebrse were, in reality, true dorsal segments, 

 seeing that he had discovered a pair of little iiidi- 

 mentary ribs attached to each of tlie osseous elements 

 m question. " The object," says Mr. Bell, " of the 

 increased number of vertebrae in the neck, is evidently 

 to allow of a more extensive rotation of the head ; for, 

 as each of the bones turns to a small extent upon the 

 succeeding one, it is clear that the degree of rotation of 

 the extreme point will be in proportion to the number 

 of movable pieces in the whole series. When the 

 habits of this extraordinary animal are considered, 

 hanging as it does from the surface of boughs with the 

 back do\\aiwards, it is obvious that the only means by 

 which it could look towards the gi'oimd must be by 

 rotation of the neck ; and as it was necessary, in order 

 to effect tills without dimuiishing the firmness of the 

 cervical portion of the vertebral column, to add certain 

 movable points to the number possessed by tlie rest oi 

 the class, the additional motion was acquired by modi- 

 fying the two superior dorsal vertebrae, and giWng 

 them Oie office of cervical, rather than mfringing on a 

 rule which is thus preserved entire without a single 

 known exception." As we shall immediately have 

 occasion to return to the consideration of the habits of 

 these animals, we have here only further to observe 

 that the Sloths are all natives of the forests of South 

 America, where they feed upon vegetable matters, 

 chiefly leaves. The extinct genera, Megatherium, 

 }iIe(jalo7ujx, Scelidotherium, Erinathopsis, and Erep- 

 todon, are also referable to this family, forming the 

 subdivision of gravirjrade edentates. 



THE AI {Dradypus tridactylus) or THREE-ToED 

 Sloth — Plate 17, fig. 55 — is the best Imown of all the 

 species. The specific term applied to it rests upon tlie 

 arbitrarily assumed grounds that it is the only species 

 which is furnished with the three toes ; but there is 

 every reason to believe that at least two otlier Sloths — ■ 

 the B. ffidaris of Eiippell, B. torquatxxs of lUiger, and 

 B. infuscatus of Wagler being regarded as so many 

 distinct species — have tridactylous feet. Be tliis as it 

 may, the generaUty of naturaUsts appear content to retain 

 the old Linnsean appellation, and we shall not deviate 

 in the present instance fi'om their combined authority. 

 The Ai inhabits the most secret recesses of tlie South 

 American forests. The body is enveloped by a coarse 

 shaggy fur, and so disposed about the short round 

 head, as to impart to the physiognomy a human look. 

 The fur has a grejnsh colour generally, young indi- 

 wdnals being frequently spotted with bro^vn and white; 

 the under parts have usually a light ftdvous tint. 

 Wlien describmg the skeleton, we took occasion to 

 remark somewhat on the habits of this animal, and 

 especiaUy referred to its awkward behaviour when placed 

 on a level surface. One of the most singular errors 

 into which the gi'eat French anatomist fell, was that 

 of ascribing to the Ais deficiencies and imperfections 

 of organization, as if they were not weU adapted to the 

 mode of existence which the Creator had been pleased 



U 



