NO. 1666. 



OSTEOLOGY OF CAMPT0SAVRU8—GILM0RE. 



219 



pressed transversely Avith a part on the lower border of the anterior 

 end, which curves in and was united with the dentary of the opposite 

 side by cartilage only (see .ss, fig. 8). Hulke's description of the an- 

 terior part of the mandible of Ilyjjs'dophodon as having a '' spout- 

 like symphysial end"' aptl}'^ describes this region in Camptosaurus. 

 ]*osterior to the symphysial surface the dentary sw^ells somewhat 

 transverseW, but remains about the same depth throughout the den- 

 tigerous part, the upper and lower borders being nearly parallel. 

 The lower border is almost straight, as shown in fig. 8. A short, 

 blunt process rises from the dorsal surface just posterior to the last 



Fig. 8. — (1) External view of left dentary, Camptosaurus. No. 1886, Yale Mu- 

 seum, I NAT. SIZE. C, CORONOID PROCESS ; m, mental foramen ; SI). SURFACE FOR 



predentary. (2) Internal view of same, c, coronoid process; mf, mandibular 



FORAMEN ; SS, SYMPHYSIAL SURFACE. 



tooth and gives support on the internal side to the coronoid (see r, 

 fig. 8). 



Just beneath the base of the coronoid process there is a deep cavity 

 (w/., 2, fig. 8) opening on the infero-internal surface of the den- 

 tary and extending forward nearly its entire length. This mandi- 

 bular fossa is present in most reptilian jaws, and in C amptosaur'us 

 is inclosed principally by the overlapping splenial. Posteriorly the 

 dentary is in contact with the angular, surangular, and prearticular. 

 The dentary unites with the predentary by an oblique surface on the 



