FOSSIL MAMMALIA. 



35 



ble, that the lower jaw, here described, must be referred, if not to the same, at 

 least to a nearly allied species of Toxodon, as that to which the large cranium 

 belonged. 



Further researches in South America, it is hoped, will lead, ere long, to the 

 completion of our knowledge of the osteology of this very remarkable and interest- 

 ing genus of extinct mammiferous animals. 



DESCRIPTION OF PARTS OF THE SKELETON OF 



MACRAUCHENIA PATACHONICA ; 



A large extinct Mammiferous Animal, referrible to the Order Pachydermata ; but with affinities to 

 the Ruminantia, and especially to the Camelida. 



In the preceding pages the nature and affinities of a large extinct Mammal were 

 attempted to be determined from the cranium and teeth exclusively : we come 

 now to consider the remains of a quadruped consisting of bones of the trunk and 

 extremities, without a fragment of a tooth or of the cranium to serve as a guide 

 to its position in the zoological scale. 



It may appear, even to anatomists and naturalists familiar with the kind of 

 evidence afforded by a fossil fragment, that an opinion as to the relation of the 

 present species to a particular family of Ruminants, formed without a knowledge 

 of the important organs of manducation, must be vague and doubtful, but the 

 evidence about to be adduced, will be regarded, it is hoped, as more conclusive 

 than could have been a priori expected. 



The portions of the skeleton of the animal— which, in relation to the affinity 

 above alluded to, as well as from the length of its neck, I propose to call Macr- 

 auchenia* — were discovered by Mr. Darwin in an irregular bed of sandy soil, 

 overlying a horizontal accumulation of gravel on the south side of Port St. Julian : 

 and independently of the circumstances under which they were found, their cor- 

 respondence with each other in size, colour, texture and general character prove 

 them to have belonged to one and the same individual. 



These remains include two cervical vertebrae, seven lumbar vertebrae, all more 

 or less fractured ; a portion of the sacrum and ossa innominata ; fragments of 

 the left scapula ; of the left radius and ulna, and left fore-foot ; the left femur 



* Mcu-pos longus, avxyv cervix : from the latter word Illiger derived Auchenia, his generic name of the 

 Llama, Vicugna, &c. 



