486 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.38. 



LEIDYOSUCHUS STERNBERGII, new species. 

 Pis. 23, 24, IT), 26, and 27. 



Holotype. — Cat. No. 6533, U.S.N.M., consists of the greater por- 

 tion of the skull, the left ramus almost entire, anterior part of the 

 right ramus, eight vertebrae in various stages of preservation, both 

 humeri, right fibula, second metatarsal of the left hind foot, and 

 other fragmentary parts of the skeleton. 



Type-locality. — North side of Cheyenne River, about .'> miles west 

 of McKeow's ranch, Converse County, Wyoming. 



Horizon. — Ceratops Beds, Cretaceous. 



Detail) (I description. — Viewed from above the form of the skull 

 resembles that of the living crocodile, although compared with Croco- 

 i/ilus nniericanus it is proportionally broader posteriorly, approach- 

 ing nearer in its general outline the skull of C. porosus. Evidently 

 the specimen is that of an adult as shown by the complete coales- 

 cence of many of the sutures. A section across the whole width of 

 the median preorbital region and extending back on the right poste- 

 rior half of this aspect has been lost through erosion. In PL 23 is 

 shown a superior view of the skull, reproduced here from a photo- 

 graph taken alter the missing portions were restored. The Lighter 

 color of the restored parts distinguishes them at once from the origi- 

 nal fossil. 



The coalesced parietals occupy the posterior median position, their 

 anterior lateral borders forming the inner boundaries of the supra- 

 temporal fossae. The least width of the parietals between these 

 vacuities is 17 nun. The posterior half of the dorsal surfaces of the 

 parietals is covered with large, deep, irregularly shaped pits, while 

 on that portion between the fossae there is a single median longitu- 

 dinal ridge with comparatively smooth tracts on either side which 

 extend laterally to a smooth, raised ridge of bone around the inner 

 and posterior boundaries of the supratcmporal vacuities. The suture 

 between the parietal and squamosal of the left side can not be dis- 

 tinguished, but as shown in /.. canadensis their union is probably at 

 the middle of the posterior boundary of the suprateniporal fossa. 



The union of the parietals with the frontal is only dimly discern- 

 ible, but on the inner anterior surface of the left suprateniporal fossa 

 the suture is quite distinct and shows clearly that the front als con- 

 tribute to the boundary of the fossa on t he superior surface between 

 the parietal and post front al. as in Diplocynodofl Pound. Two de- 

 tached but. broken parts of the frontal bone, which were found near 

 this specimen and which supplement each other, may. from their 

 size and sculpturing, be considered as belonging to the present species, 

 and shows that this bone \\;is broad behind and narrow in front. In 

 the type skull the side of the frontal is excavated for ;i distance of 



