11 



the teeth of the Sloths and Armadillos, I have ascertained by this mode of inves- 

 tigation, that the teeth of the Megatherium have the same texture and compo- 

 sition as those of the Sloth *. And if from identity of dental structure in two 

 different animals we may predicate a similarity in their food, a glance at the bony 

 frame-work of the Megatherium is sufficient to show that it must have resorted 

 to other means of obtaining its leafy provender than that of climbing for it ; 

 whereby the necessity of inferring a proportionate magnitude of the trees which 

 nourished the Megatherium is obviated. 



This argument will be resumed, in connexion with a survey of the grounds 

 of the conflicting hypotheses of the habits of the Megatherioid quadrupeds above 

 quoted, at the conclusion of the description of the skeleton which is the imme- 

 diate subject of the present memoir. Such description, however, would have 

 been both less instructive and less interesting without the antecedent sketch of 

 the principal facts ascertained in regard to the Megatherium : and, reciprocally, 

 the scientific knowledge of the Megatherium will, it is hoped, be both increased 

 and established by the details of the osteology of the Mylodon. For it cannot 

 be concealed that doubts have been expressed, and still may be entertained by 

 some comparative anatomists, as to whether the famous skeleton at Madrid be 

 actually composed of bones of the same species, not to say individualf . Pro- 

 portions of a pelvis and of thigh-bones, surpassing those in the Elephant, have 

 been deemed to be preposterous in combination with a cranium not exceeding 

 in size that of the Rhinoceros, &c. And these doubts have not been materially 

 diminished by the remains of other Megatherioid animals discovered before the 

 arrival of the skeleton of the Mylodon. 



The Megalonyx, for example, a large extinct species of the order Bruta, allied 

 to, but less than the Megatherium, has hitherto been recognised by portions of 

 the skeleton too fragmentary and unconnected to throw light on the question of 

 the true form and proportions of its gigantic congener. 



The parts of the Megalonyx described in the posthumous edition of the ' Os- 

 semens Fossiles:j:,' are two portions of teeth; the metacarpal and phalangeal 



* Zoology of the Beagle, Fossil Mammalia, 4to, 1839, p. 103, pi. 32, fig. 1. 



t Prof. Lichtenstein, in Schmeisser's ' State of Science in France," torn. ii. p. 95, quoted by Cuvier, 

 loc. cit. p. 336. 



: Tom. viii. pp. 304-330. 



b2 



