26%. KANSAS UNIVERSITY QUARTERLY. 
The premaxillary is more or less plate-like, externally it is con- 
vex from before backward. The anterior border is quite oblique 
and forms an acute angle with the alveolar border. There is prob- 
ably no close connection with its fellow on the opposite side. The 
upper portion of the bone is covered with fine lines radiating 
upward and backward from the tip. The teeth seem to be some- 
what smaller than those on the maxillary; alveola for nine are 
found. 
The ramus of the mandible decreases more in depth toward the 
symphysis than in either /chthyodectes or Portheus, the lower por- 
tion is very thin, becoming gradually thicker towards the alveolar 
border but does not attain the robustness of this portion in Por- 
theus. Just back of the predental surface and below the line of 
foramina occurring opposite the roots of the teeth there is a prom- 
inent swelling more strongly marked than in Dapéénus. The pre- 
dental surface is almost vertical and is very irregular for cartilage 
attaching it to the predentary. Just back of this and below the 
swelling mentioned above, internally, there is an elongated ovoid 
pit near the point of the Mento-Meckelian ossicle of A4mza The 
posterior portion of the dentary is well elevated above the articu- 
lar. The groove for Meckel’s cartilage is not so deep as in Por- 
theus. From the center to the anterior extremity the teeth decrease 
in size, on the posterior portion they are about twice as large as 
those on the superior maxillary; the crowns are compressed and 
appear minutely striate under the microscope. Just beneath the 
dentary there is a long, thin element extending nearly its whole 
length, which appears to be joined to it by a suture. If this be 
true it may represent a new element in the jaw, although more 
material will have to be brought to light before this point can be 
determined. 
The predentary is a triangular element joined to the dentary by 
a very irregular surface broader above than below. The superior 
borderis finely rugose and edentulous. The tipis acute. The two 
rami were probably united by ligaments at the symphysis, as in the 
Mosasaurs. 
The articular sends a long dagger-like element forward inter- 
nally nearly to the ovoid pit mentioned above. Externally it is soon 
covered by the dentary. The cotyloid cavity has its surface more 
vertically directed than in either Portheus or Ichthvodectes; it 1s 
narrower laterally and slightly concave from above downward. 
Externally a lamina of bone extends backward probably articu- 
lating with the angular below. 
