CORYPHODOK 
205 
I gave the general characters of the skull, and of the hind foot, determin¬ 
ing the number of toes in the latter. The temporary dentition and three 
new species were also described. In some remarks before the Academy 
of Natural Sciences of Philadelphia, made March 9, 1875, I pointed out 
the near relation of these animals to the species of Corypliodon. In the 
‘‘Systematic Catalogue of Vertebrata of the Eocene of Wyoming”, April, 
1875, the structure of the fore foot, including the number of digits, was 
pointed out, and the group Pantodonta removed, with the Binocerata, to a 
new order, the Amhlypoda; Corypliodon was referred to the Pantodonta^ and 
two species were added. I announced the generic identity of tire American 
and European forms in a communication before the Academy of Phila¬ 
delphia, made April, 1876 (published April 26), pointing out the subordinate 
characters of the respective types.* The present work completes the descrip¬ 
tion of the osteology, so far as accessible to me; and I may add that this 
is so far complete that there only remain unknown the number of the ribs 
and dorsal and lumbar vertebrae, and the structure of the hyoid apparatus. 
Species. —Eemains of more than one hundred and fifty individuals of 
this genus were procured by the expedition, and these indicate the existence 
of a number of species. Their characters may be observed in the teeth, 
the forms of the astragalus, calcaneum, and other bones. The precise 
definition of all of these species is a matter of some difficulty, as I have 
been compelled to rely chiefly on the mandibular teeth for the characters, 
owing to the more irregular occurrence of other elements; and the tubercles 
of the teeth are not always constant. The following key expresses the 
relations of these forms, most of which, perhaps all, are good species: 
I. Posterior inferior molars with an accessory cusp or tubercle on the 
inner side between the crests {Corypliodon., Owen): 
An internal conic cusp; posterior crest oblique; heel very 
small; size medium. C. cuspidatus. 
An internal crest; posterior crest oblique; heel small; size 
medium. C. ohliquus. 
An internal tubercle; posterior crest little oblique; heel large; 
size large. C. lobatus. 
* A short time after this, O. C. Marsh asserted the identity of Corypliodon and 
Batlmodon in the Amer. Journ. Sci. and Arts. 
