48 UPPER CRETACEOUS TELEOSTS 
row are the smallest. The 11 sockets would presumably indicate the presence of 
about 5 or 6 functional teeth together with their replacements. The posterior 
tooth of the palatine and the anteriormost tooth of the ectopterygoid are equal in 
size and are the largest teeth in the upper jaw. The teeth of the inner row are 
closely arranged, and their bases are ovoid in shape. The outer row of teeth is 
of less importance and is represented by smaller unbarbed teeth, which, unlike 
the inner row, reach their maximum size half way along the bone and decrease in 
size anteriorly and posteriorly. There are 8 tooth bases present, again probably 
functional teeth and their successors. Unlike the inner row, the sockets are not 
quite so crowded together and have a more circular outline. Loomis (Igor) has con- 
sidered the histological structure of the teeth of certain species of this genus from 
the Niobrara Chalk of the United States. 
Fic. 21. Cimolichthys levesiensis Leidy. Restoration of the skull in lateral view. 
Dermal upper jaw. The dermal upper jaw is shown in lateral view in Text-figure 
21. The jaw consists of a premaxilla, a maxilla and a small supramaxilla. The 
premaxilla is a large, antero-posteriorly elongated lamina of bone, tapering at 
both ends. It is more than four times longer than its maximum depth and its lateral 
face is ornamented with radiating rows of small bony tubercles. The tubercles 
radiate ventrally from a point near to the dorsal border of the premaxilla at the region 
of its maximum depth which is just within the anterior half of the bone. Anteriorly 
the premaxilla curves around the acutely pointed snout and probably contacted its 
partner in the mid-line. The oral border of the premaxilla bears a single row of 
small, conical, closely arranged teeth. 
