APPENDIX. 
After the foregoing paper on Ancodus was completed, the Princeton Museum 
received an umisuiilly large and line skull appertaining to this genus from the White 
. River bad lands of South Dakota. The specimen was found in the Metamynodon 
division of the Oreodon-beds, and appears to represent the same species as that re- 
I'erred by Osborn and Wortman to the A. americanics of Leidy. (Bull. Amer. Mus. 
Nat. Hist., New York, Vol. VI, p. 219.) Leidy ’s species, however, was found in 
the Titanotlierium-beds, which affords a pi’esumption against its being identical 
with the specinien before us. As in the skull-fragment described by Osborn and 
Wortman, the first upper premolar is wanting, an evidence of the constancy of this 
character. The principal differences from A. americanus which may be observed 
in the dentition are two: (1) has a imich better developed cingulum, especially 
upon the inner side of the crown. (2) In the upper molars the external buttresses 
or styles are decidedly less conspicuous, the median buttress (mesostyle) is divided 
by a deeper cleft and has a tuberculated or crenulated edge. 
The differences from A. brachyrhynchus are very distinctly marked. (1) VI is 
absent and the muzzle is much more elongated. (2) The palatal notches are much 
more deeply incised and extend farther forward. (3) The posterior nares are not 
displaced so far backward and have a (piite different shape, the palatines forming a 
long and pointed median projection from the anterior border. (4) The size of the 
animal is greater. Imleed, this skull is distinctly the largest of this genus that 
has yet l)een reported iroin the White River formation. 
1 be mandible has a very shallow, though quite thick, horizontal ramus, with 
a long and narrow symphysis, the chin expanding into a spatulate shape at the in- 
cisive alveolus. 
llie new species may be called Axconus kostratus; in apipearance it ap- 
proaches most nearly to the European species, A. velaunus. It is altogether likely 
that the large hind-foot, described and figured in the foregoing paper under the 
name Ancodus sp., belongs to A. rostratus. 
MEA.su HEM ENTS. 
Skull, extreme length 
“ length from oeciiiital eomlyles ! . 
“ of cranium 
‘ “ of face . . . 
Diastema between canine and nil ' 
Uength of ui)|)er iiremolar-molar series . 
“ premolar series .... 
Length of upper molar series .... 
Hard palate, length 
Diastema between canine and pi . . 
. .090 
“ “ pi and . . . 
Length to ms, Inclusive 
. .120 
“ of lower molar series .... 
. .0.51 
Depth of mandible at mS . . . 
( 536 ) 
