no. 1762. 



A NEW FOSSIL CROCODILE— GILMORE. 



499 



Though the evidence is not entirely conclusive, it would appear 

 from the occurrence of an open median suture at the posterior border 

 of the external nares, that the nasals did not reach the narial opening. 



That the skulls discussed in the preceding pages do not represent 

 the largest individuals of this genus is shown by an incomplete mandi- 

 ble (Cat. No. 984, American Museum of Natural History) whose total 

 length from the tip to the broken end below the middle of the articular 

 portion of the articular bone measures 403 mm. The same measure- 

 ment taken from the left ramus of the type of L. stembergii is 343 mm. 



The alveolar border of the dentarv shows alveoli for twenty-one 

 teeth as in the type of the species mentioned above. The sculpturing 

 is somewhat coarser, but this is probably an age characteristic. The 

 splenial, as in the other specimens, enters the symphysis, but the 

 extent of its contribution can not be accurately determined. 



The ramus was collected by Mr. Barnum Brown near the top of the 

 Hell Creek Beds, 350 feet above the Pierre, 16 miles north of Jordan a 

 and about 135 miles northwest of Miles City, Montana. 



Measurenu nts of skulls of Leidyosuchus stembergii. 



Length of skull on median line 



Length of skull in front of orbits 



Transverse diameter of skull, outer angles of quadrates. 



Transverse diameter of skull, front of orbits 



Transverse diameter of snout across level of tenth tooth 



Transverse diameter of snout across premaxillaries 



Least transverse diameter of snout at notch 



Longitudinal diameter, orbital opening. 



Transverse diameter, orbital opening 



Genus LEIDYOSUCHUS. 



The genus Leidyosuchus was founded 6 by Lambe upon crocodilian 

 remains from the Judith River (Belly River) formation of Alberta, 

 Canada. Lambe says: "The material from Red Deer River includes 

 a left mandibular ramus, the posterior part of a cranium, portions 

 of 1 he skull, teeth, and a number of vertebrae and scutes. Of these 

 specimens the ramus of the lower jaw is selected as the type of the 

 species; the other specimens, of which the back portion of the 

 cranium may be regarded as the cotype, are associated with the 

 type." 



"The geographical Location of these specimens (Cat. Nos. tisi and 5898, American 



Museum of Natural History i i< well shown on a small sketch map of the western half 

 of Dawson County, Montana, published by B. Brown. Bull. Am. Mus. Nat. Hist., 

 vol. 2:5, 1!)()7, fig. I 

 & Trans. Royal Sue Canada, vol. 1, L908, pp. 219 235, pis. 1-5. 



