294 



PATAGONIAN EXPEDITIONS! PALEONTOLOGY. 



MEASUREMENTS. 



Metatarsal V, proximal thickness ... .019 



First phalanx, digit III, length 020 



" " prox. width . .016 

 thick- 

 ness . .024 

 " distal thick- 

 ness. .019 



First phalanx, digit IV, length 016 



" " prox. width.. .013 

 " distal width .. .oil 

 thick- 

 ness . .014 



First phalanx, digit V, length oil 



" " " " prox. width.. .009 



" " " thick- 

 ness . .015 



" " " " distal thickness .007 



Second phalanx, digit III, length . . . .030 



" " prox. width .015 



Second phalanx, digit III, prox. thick- 

 ness . .019 

 " distal thick- 

 ness . .020 



Second phalanx, digit IV, length . . . .03 1 

 " " " prox. width .012 



" thick- 

 ness . .019 



" " " " distal thick- 



ness . .0165 



Second phalanx, digit V, length 018 



" " prox. width .008 

 " " " thick- 

 ness . .013 

 " " distal thick- 

 ness . .008 



Ungual, digit IV, length 06 1 



" " " proximal width 013 



" " " " thickness . .021 



Relationships. As remarked above, it is a matter of some uncertainty 

 whether the two species referred to Analcimorphus really belong to the 

 same genus ; probably they do and almost certainly they are very closely 

 allied, if not congeneric. In what follows, however, attention will be con- 

 fined to A. giganteus, because of the relatively full information concern- 

 ing that species which we possess. The entire structure of the skeleton 

 shows that the present species is a member of the Megalonychidce and, in 

 particular, that it is nearly connected with Schismotherium and Pelecyodon. 

 At the same time, there are many points of resemblance to the Planopsidce, 

 to which group Ameghino has referred the genus ; the dentition, several 

 characteristic features of the skull and the proportions of the pelvis pre- 

 sent the most obvious of these approximations to the Planopsidce. To a 

 certain extent, therefore, the present genus is a connecting link between 

 the two families, although it cannot itself be placed in the line of descent, 

 because it is contemporaneous with the differentiated Planopsidce; it 

 should, on the contrary, be regarded as a derivative of the common an- 

 cestor of both families and so little removed from that ancestor as to indi- 

 cate its probable character. 



