no. 1762. A NEW Fossil. CROCODILE GIL.MORE. 4S ( .I 



vacuity measure only 2:> mm. in transverse diameter. Their sutural 

 union with the pterygoids, owing to the damaged condition of this 

 part of the palate, can not be determined. 



The posterior palatine vacuities are comparatively large, measur- 

 ing 101 mm. longitudinally and 34 nun. transversely. The anterior 

 border of these vacuities is opposite the twelfth maxillary tooth, as 

 in Diplocynodon. 



The pterygoid of the left side is practically entire and lias suffered 

 no distortion. It extends downward and backward from the gen- 

 eral level of the palate at an angle of 45' . The postpalatal vacuities- 

 encroach but little on the pterygoids. The preservation of the back 

 border of the posterior aperture of the nasal passages is sufficient to 

 establish its position as being wholly surrounded by the pterygoids. 

 There is a bridge of bone 12 mm. wide separating this opening from 

 the posterior median border of the pterygoids which leads down to 

 the median Eustachian foramen. (See PI. 24.) In all modern 

 crocodiles these two openings are separated by only a thin septum 

 of bone. In this respect L. stembergii from the Cretaceous is inter- 

 mediate between those early Triassic and Jurassic forms having the 

 posterior narial opening well forward on the palate, and the Tertiary 

 crocodiles where it has receded posteriorly to a, position nearly, if 

 not cpiite, as far as in modern crocodilians. The posterior border of 

 the conjoined pterygoids is notched, the notch being the interval 

 between two thin diverging processes from the back part of the 

 pterygoids. The form of the posterior nares can not be determined 

 from this individual. 



The transpalatines connect the pterygoids with the maxilla, as 

 shown in PI. 24. 



In the posterior view of the skull (PI. 2b) hardly any of the sutures 

 can now be distinguished, and a comparison of this aspect with the 

 excellent figures given by Lambe of Leidyosuchus canadensis, only 

 serves to give one an approximate idea of the relations of the several 

 elements comprising the occiput. In the proportion of its breadth 

 to its depth, L. sternbergii differs from L. canadensis in the considera 

 bly less vertical extent of the coalesced (dements overlying the fora- 

 men magnum, in the shortness vertically of the descending pari of 

 the basioccipital, and in the comparative'lightness, both horizontally 

 and vertically, of the condyle of the quadrate. In the latter respect 

 it approaches Diplocynodon Tiautoniensis of the London Clay. 



The basioccipital is deeper than broad, and viewed from behind 

 almost hides the basisphenoid which lies in fronl of it. Between 

 these two bones at their lower extremities is I lie opening for the 

 median eustachian canal. (See m. <. c, PL 26.) Below the occi- 

 pital condyle on the median posterior surface of the basioccipital a 

 prominent sharp vertical keel is developed which is even more pro- 



