488 PROCEEDINGS OF THE VATIONAL MUSEUM. vol.38. 



The premaxillae inclose the heart-shaped externa] nares, but it 

 can Qot be determined from this specimen whether or not the nasals 

 extended Into this opening. In Diplocynodon liautoniensis (Wood), 

 which Owen figures in his monograph" under the name Crocodilus 

 liastingsise, the nasals do not reach the narial opening, and taking into 

 account the many oilier resemblances it may be that the same condi- 

 tion prevails in the nasals of Leidyosuchus. Lambe, from incomplete 

 evidence, was inclined to believe the nasals reached ;i point in advance 

 of the maxillaries in L. canadensis, and if his observation be correct, 

 i he\ at least approach the nares more closely than in I)i/>/<>ci/m»/(>h. 



The post erior extent of the facical processesof t he preniaxilhe can not 

 be determined, although the maxillo-preniaxillary and maxillo-nasal 

 sutures can be traced (see PI. 23) back as far as the missing facical 

 section previously mentioned. Latero-inferiorly the posterior bound- 

 ary of the preniaxillary is at the back of the notch behind the fifth 

 tooth, where the maxillo-preniaxillary suture passes on to the palate. 



The supratemporal fossa 1 are of good size and subellipt ical in shape, 

 measuring .'!■'! mm. longitudinally and 23 mm. transversely. The 

 orbit communicates with the infratemporal fossa. The latter are 

 slightly smaller than the supratemporal fossa' and angularly rounded. 

 The left fossa, the 1 borders of which are nearly intact, measure's about 

 _'.") nun. both transversely and antero-posteriorly. 



The orbits are large and look upward and forward, with their inner 

 borders everted as in the alligator. The greatest longitudinal diame- 

 ter of the left orbit is 55 mm. and the transverse diameter 38 nun. 



The inferior or palatal surface is more complete than the dorsal, 

 lacking only tin 1 posterior ends of the palatines, the right pterygoid, 

 transpalatine, and posterior half of maxillary of same side. The 

 anterior palatal region is decidedly concave transversely, and between 

 those elements which have not suffered mutilation all of the sutures 

 .lie plainly distinguishable. The palatine processes of the premaxillae 

 reach the level of the aveolus for the first maxillary tooth, the pos- 

 terior ends being rounded. In this view the premaxillae inclose a 

 small rounded anterior palatine vacuity which measures L2 mm. 

 longitudinally and 1.'! mm. transversely. 



The anterior processes of the maxillae extend forward on the median 

 line to the Level of the middle of the notch which separates the maxil- 

 lary and preniaxillary dental series. 



The palatines meet the maxillae ;it the center by a, nearly straight 

 transverse suture opposite the tenth maxillary tooth. The median 

 posterior processes of the maxillae extend back on tin' -ides of the 

 palatines to a point opposite the thirteenth maxillary tooth. The 

 palatines are narrov* and at the middle of the posterior palatine 



" Monograph of the Basil Eteptilia of the Lon<l<m (lav. |>i. -. 1850, pp. t_ -I I. pi. <>, 

 fig. 7. 



