1885.] 



NATURAL SCIENCES OF PHILADELPHIA. 



197 



The Tarsus is somewhat longer than in the moose, of about 



the same length, but narrower than 

 in Megaceros. The calcaneum is 

 nearly an inch longer than in either 

 form, giving a prominent " hock- 

 joint." In the smaller bones of the 

 tarsus we find some curious relations. 

 On the left side the arrangement of 

 these bones is nearly the usual one 

 among the Cervidse. That is to say, 

 the cuboid and navicular are fused 

 into one bone, the second and third 

 cuneiforms into another, but, strange 

 to say, the first cuneiform is firmly 

 ankylosed with the metatarsus, form- 

 ing a little step against which the 

 compound cuneiform abuts. In the 

 right foot the process of ankylosis 

 has gone further and gives a tarsus 

 which is even more concentrated than 

 fig. 7. in the Tragulina. (See fig. 7). The 



Right Tarsus of Cervalces Americanus. compound Cuneiform is fused with 



the cubo-navicular (fig. 7, N. and Gb. and (7., 2 and 3), and the 

 first cuneiform, as in the left foot, with the metatarsus (fig. 7, G 3). 

 This fusion of tarsal bones with the metatarsus is very curious. 

 It does not occur in any known ungulate, and I am acquainted 

 with no other mammal in which it can be found. A tarso- 

 metatarsus, in the same sense, but to a less degree, as in birds, 

 is thus formed. 



The Metatarsus is very long, and of about the same propor- 

 tions as in the moose. 



The Phalanges of the median digits are a little longer than in 



the fore-foot, those of the rudimentary digits of about the same 



size. 



Conclusion. 



Cervalces Americanus is a very interesting form, and offers 

 some morphological suggestions of great value. Geologically it 

 teaches little that was not known. Its occurrence so far south 

 of the moose '8 range, points to a colder climate than the present, 



