no. 1762. 1 V/:ir FOSSIL CROCODILE— GILMORE. 493 



By referring to the table of measurements it will be observed that 

 the dimensions of the ramus of the specimen under consideration are 

 almost identical with those of the holotype of L. canadensis. 



Viewed from t ho side the alveolar border is undulating, while the 

 lower side from a point just posterior to the external mandibular 

 foramen presents a nearly straight border to the upturn of its exl rem- 

 ity near the symphysial end. The external mandibular foramen is 

 relatively large and in outline has the form of an elongated ellipse. 

 (Seee. m. /., PI. 25.) 



The internal mandibular foramen is relatively small, and in rela- 

 tion to the large external foramen is located more posteriorly than in 

 living crocodilians. The position of this foramen is well shown in 

 PL 27 (i.m./.). 



In the region of the eighth tooth the dentary is constricted, but 

 anteriorly it widens both inward and outward, reaching its maxi- 

 mum breadth in line with the fourth tooth, with a transverse diame- 

 ter of 32 mm. Posterior to the constriction the alveolar border 

 ascends rapidly to the position of the twelfth tooth. From this point 

 posteriorly the upper border rises gradually with a gentle concave 

 curve, thus adding considerably to the depth of the jaw. The maxi- 

 mum depth of the ramus is just posterior to the external mandibular 

 foramen, where it reaches 53 mm. 



The dentary articulates in the usual manner with the surangular 

 above and the angular below. The upper posterior prolongation 

 of the dentary, however, does not extend so far back over the external 

 foramen as in living crocodiles. The anterior extension of the angular 

 is received between the dentary and splenial, terminating under the 

 alveolus for the nineteenth tooth. The external surfaces of both the 

 angular and surangular, especially the former, are roughly sculptured 

 (well shown in PI. 25). The irregular pitting of the upper half of the 

 externa] surface of the angular is succeeded below by long, somewhat 

 irregular grooves and ridges which conform to the curves of the lower 

 margin of the jaw. The dentary along the whole of its outer and 

 under surface is pitted by numerous vascular openings leading 

 obliquely forward into the interior of the bone. These openings 

 become more numerous anteriorly, and on the lower part the surface 

 is roughened by numerous longitudinal grooves. 



The splenial covers the whole inside of the ramus back to the 

 internal mandibular foramen. Just behind the symphysial union, 

 the splenial is pierced by a small, longitudinally elongated foramen 

 which leads into the meekelian groove. Lambe has shown " thai 

 beneath this opening there is a small foramen in the dentary leading 

 into the dental canal. Unlike the type of L. canadensis, the bony 



"Trans. Royal Soc. Canada, vol. 1, 1898, i>i>. l'2:;-_'l' I. 



