488 Professor H. G. Seeley — Dentition of Cynocjnathus. 



of four foramina corresponding in position with the bases of the roots 

 of molar teeth. There are also tliree or four smaller foramina further 

 forward, nearer the alveolar border, which have no obvious relation 

 to dental nutrition. There are several small, scattered, vascular 

 foramina above the diastema in advance of the maxillary canine tooth. 



In the original description the external surface of the anterior 

 bulbous part of the maxillary bone of C. crateromtus is only referred 

 to as being irregular with undulating depressions and convexities. 

 In C. Berryi the bone shows a finely pitted ornament of a radiating 

 sub-crocodilian type, in advance of the sub-orbital foramen. 



In this maxillary bone the ornament (PL XXIV, Fig. 2) consists 

 of close-set, small bosses with concave summit-surfaces, surrounded 

 by depressions, which are divided into groups by sub-parallel winding 

 longitudinal canals, with vertical connecting branches. Two or three 

 of these sinuous, vascular channels close together are below the sub- 

 orbital foramen, one is level with it, two are above and wider apart. 

 Some short oblique canals descend upon the convexity of the root 

 of the canine tooth, giving that part of the bone a fluted or folded 

 aspect. The pitted ornament is most dense in the central area above 

 the imbedded root of the canine tooth, and is less distinct downward, 

 forward, and upward to the nasal suture. 



The maxillary bone is exceptionally strong, averaging -or of an inch 

 thick at the posterior fracture, and thinning away in front and above 

 to the squamous premaxillary and nasal edges. Its transverse width 

 on the palate at the canine tooth is l-i-Q-inch, giving the snout a width 

 of about 3^ inches by allowing for the left maxillary. 



The internal surface of the bone above the palate and below the 

 wrinkled sutural surface for the nasal bone is smooth, convex over the 

 oblique root of the canine tooth, and excavated concavely below and 

 behind it, owing to the inward extension of the maxillary plate which 

 forms the palate. 



The palatal surface of the maxillary bone contracts in width behind 

 the canine (PI. XXIV, Fig. 1), It is 1^ inch wide over the first 

 molar tooth, and about l-A- wide at the posterior fracture. Anteriorly 

 the palatal width decreases towards the premaxillary suture. 



The crowns of all the teeth, canine and molars, are broken off level 

 with the alveolar margin of the jaw, so that no trace is preserved of 

 the characteristic forms of the molars of Cynognathus. The base of 

 the crown of the canine is slightly ovate, compressed on the inner 

 hinder side, implanted obliquely, directed forward, downward, and 

 outward. It is 1 inch from front to back and -^o inch transversely. 

 The fracture shows a small pulp cavity. 



Behind the canine is the triangular area which indicates the remnant 

 of the base of the milk or first canine, which was removed by 

 absorption (PL XXIV, Fig. 1). That tooth-fragment is obscure, but 

 may have been fractured during the life of the animal. The absence 

 of a tooth in this position gives the jaw laterally the aspect of having 

 a small false diastema. 



The molar teeth extend backward in a line with the inner border 

 of the canine tooth. They vary in size, but the oval roots of the 

 first five are contained in a length of l-n,- inch. The first has a sharp 



