284 Quadrupeds. 



" the inverted position of the soles of his hind feet." Dr. Lund, how- 

 ever, saw enough in the living sloth to lead him to very decided con- 

 clusions respecting the extinct Megalonyx ; differing however, as they 

 do, from those of Professor Owen, we presume not to speak of them 

 as conclusive. 



" Now, the Megalonyx, like the sloth, is provided with powerful clavicles ; like it, 

 also, its anterior extremities are longer than the hind ; its toes are armed with immense 

 claws ; and lastly, the sole of its hind foot is turned inwards instead of downwards. 



" The first of these characters, or the existence of perfect clavicles, proves that this 

 animal used its fore extremities for more purposes than for walking ; which position 

 I take to be incontrovertible, as it is founded on a rule that has no exception among 

 mammals. The purposes for which mammals, provided with clavicles, employ their 

 anterior extremities, are the following : — 1st, for flying, as in the bats, with which we 

 have here nothing to do; 2dly, for the apprehension of food, and the bringing it to the 

 mouth, either with one hand, as in the apes, or with two, like most rodents, some mar- 

 supials, &C. Now, the first of these purposes requires a peculiar disposition of the fin- 

 gers, and a certain freedom of motion in them ; which conditions are both wanting in 

 the Megalonyx, notwithstanding this animal, as well as the Megatherium, has in re- 

 ality been classed by Wagler among apes. The second purpose is confined to animals' 

 that have short fore-limbs, and whose dental system is adapted to gnaw substances 

 which they hold in their paws ; which conditions being also inapplicable to the Mega- 

 lonyx, there can be no occasion to dwell longer on them. Thirdly, for tearing asunder 

 their prey, as in the feline tribes. This purpose requires only an imperfect develop- 

 ment of the clavicles, but at the same time, a peculiar anangement in the shape and 

 attachment of the claws; which, again, is not the case in the Megalonyx. Besides, 

 the dental system proves it to have been graminivorous ; although authors have not 

 been wanting (as Jefferson and Faujas) who have placed it among the Carnivora. 



"There remain, therefore, only two functions that are exercised by animals provided 

 with bones for the attachment of claws ; viz., digging and climbing. And it is the 

 more necessary to confine our attention to these two points, inasmuch as we see that 

 all animals belonging to the same order as Megalonyx, exercise one or the other 

 of these functions. Their immediate instruments for these purposes are claws, which 

 consequently are powerfully developed in all ; but in none in so high degree as in the 

 extinct genera Megalonyx and Megatherium : in these they have reached the highest 

 degree of development we yet know in the animal kingdom. It would be contrary to 

 all experience in Natural History, to suppose that an organ should lose its function 

 and significance precisely at the point where it is most perfectly developed. We can- 

 not doubt, therefore, that the powerful claws with which we find Megalonyx and Me- 

 gatherium armed, have had their use. We may even conclude with certainty, that 

 the habits of the animals were closely connected with these organs, and that their very 

 existence depended on them. Now, as we only know of two uses for strong claws in 

 mammals, digging and climbing ; and as these two purposes require diff'erent anato- 

 mical arrangements ; it will not be very difficult to decide for which of them the pow- 

 erful organs in the extraordinary creatures we are considering were intended. We find 

 among the animals the most perfectly organized with respect to burrowing, such as 

 the mole Sic, that the clavvs are strong, long, broad, and nearly of equal size, that all 

 (he dibits arc provided with similar claws, and arc extended in almost the same plane 



