1872.] 347 * [Cope.. 
hibits a strong longitudinal ridge. The extremity of the dentary takes 
a wider curve from the symphysis than in P. caninus, giving a broader 
chin (whence the name) and muzzle. The symphysis is smooth transverse 
trilobate, the two outer lobes being separated by an emargination in the 
position of the foramen mentale. This form is very different from that 
in P. caninus where the symphyseal surface is sub-round. 
The anterior teeth are smaller than the median, and have the inner 
alveolar wall nearly as much elevated as the external. The crowns are 
scarcely distinguishable from those of the P. caninus, being curved conic, 
with round section and smooth cementum. They form a single incurved 
row next the symphysis. Number of teeth in an inch at middle of ramus, 
4.5. 
From a caiion near the Smoky River near to the Jethyodectes anaides m. 
PACHYRHIZODUS SHEARERI. Cope. sp. nov. 
Associated with the bones of the P. caninus is a slender bone of oval 
section, which is marked on one edge by twenty-two transverse alveoli 
whose outer margin are a little higher than the inner. No teeth pre- 
served. It may belong to a fish of this genus, and is probably a superior 
maxillary bone. Constantly with this position its outer extremity is 
more compressed than the proximal, the thickening being especially seen 
in the superior margin. <A shallow concavity passes obliquely across this 
border from within outwards and distally as in P. caninus, but the articu- 
lar face is not preserved. There is a longitudinal angle on the external 
face, and the superficial layer of bone is nowhere grooved or rugose. The 
pleurodont character of the tooth attachment is more marked proximally. 
Length of piece, M. .041 ; vertical diameter, .007; greatest transverse do., 
-0033. 
This species is dedicated to Doctor Shearer, Assistant Post Surgeon, to 
whose interest in the subject, the Geology of Kansas is indebted for many 
useful discoveries. 
EMPO. Cope. 
In this genus the character of the teeth is quite similar to that of the 
preceding group, but the arrangement on the maxillary bone is different. 
The characters are : 
Maxillary teeth anteriorly in two series, an external marginal of sub- 
equal teeth, and an innerand superior of probably small extent, but which 
‘terminates anteriorly in two large canine teeth. 
Only one species is known to me. 
EMPO NEPAHOLICA. Cope. sp. nov. 
Established on a portion of the right maxillary bone of a single individ 
ual. It displays the anterior squamosal suture for the premaxillary, and 
not far posterior to this on the superior margin, a concavity for contact 
with palatine, pre-frontal or other bone as the case may be. The pos- 
terior portion is lost. The premaxillary sutural margin extends at right 
