183 



claw-bones of placental Felines, but resembling those phalanges, rather than the non- 

 retractile ones of the Marsupials above mentioned, in the proportion of depth to length 

 and breadth. 



A claw may be adapted to pierce, retain, and lacerate (as, for example, the large 

 sheathed one of Myrmecophaga jubata), and be used as a weapon against a mammal of 

 equal or superior size only in defence (as when the great Anteater causes the death of 

 its assailant the Jaguar by the tenacity of its grip). So, likewise, may the claws of the 

 Megatherioids have been put to such occasional defensive uses against their probable 

 assailant the Machairodus neogwus, although, as in the Anteater, the habitual service 

 of the claws may have related to insects or vegetable diet. 



One is guided in a conjecture as to the uses of claws by the evidence afforded by the 

 associated fossils of the animals which, if unguiculate, would have had claw-bones of the 

 size of those under consideration. 



No evidence of a Megatherioid or other Edentate animal has been had from any cave 

 or fossiliferous deposit in Australia. The shape of the ungual phalanges in Kangaroos 

 and Wombats is known. The ungual phalanges (Plate X. figs. 11-14) are too small 

 for Nototherium and Diprotodon, if even one were to entertain the idea of those huge 

 Marsupial Herbivora having had sheathed, compressed, decurved, pointed claws, like 

 those which the plalanges in question plainly bore. These phalanges are as much too 

 large for the Thylacinus and Sarcophilus. But there is no other associated Carnivore 

 corresponding in size with that of the animal indicated by them, save the Thylacoleo. 



It is open to any one to repeat, with respect to these phalanges, the remark which 

 has been made on the fossil metacarpal of the carnivorous type from Australia (Plate XIII. 

 figs. 6, 7, 8), the size of which is such, as the articular surfaces (a in figs. 11, 12, 13 & 14, 

 Plate X.)show, to have entered into the formation of the paw terminated by such claw- 

 phalanges, viz. "That the metacarpal bone figured in Phil. Trans. 1859, Plate xin. 

 belonged to the same animal as the skull is only conjectural"*. 



All that has been above advanced in searching out the nature of the ungual phalanges 

 made known to me by photography is conjectural ; but if a Palaeontologist or Compa- 

 rative Anatomist is willing to lend friendly aid in such difficult gropings after the things 

 of the past, he should point out in what particulars he deems the grounds of the con- 

 jecture to be defective. 



A great proportion of the fair edifice of Palaeontology still rests upon a scaffolding of 

 wise and well-founded " conjecture." 



* XII. p. 309. 



10* 



