MARYLAND GEOLOGICAL SUEVEY 13 



separate in the median line. The frontal appeared at the posterior 

 end of the maxillaries as a heavy flattened process overhanging the 

 •orbit, the outer edge of which was thick and depressed in the vertical 

 •direction. The basisphenoid has strong descending lateral processes 

 that carry backward the pterygoid ridges, thus giving to the base of 

 the skull much the appearance of the modern dolphins. The occipital 

 condyle stood well out from the body of the bone; the occipital bone 

 joined the squamosal at a very large angle so that the posterior edge 

 of the zygomatic portion is almost as far back as any part of the skull ; 

 this gives a very wide back to the skull with a rather sharp angle 

 between the sides and the back. The tympanic is rather simple in 

 form. It is especially characterized by the slender trough-like exten- 

 sion of the anterior edges of the lips; the posterior side shows a wide 

 shallow groove quite rugose on the sides and bottom. 



Measurements : 



From end of snout (incomplete) to posterior end of 



symphysis 445 m. 



Posterior end of symphysis to posterior end of ramus .199 m. 



"Width between posterior ends rami 14 m. 



Width jaw at symphysis 05 m. 



Width of jaw at about half the length 03 m. 



Width jaw at anterior end, as preserved 01 m. 



Number of teeth in five centimeters 3 



Occurrence. — Calvert Formation. % mile north of Governor's Eun. 

 Collection. — Maryland Geological Survey. 



Priscodelphinus uraeus Cope. 



Tretosphys uraeus Cope, 1869, Proc. Acad. Nat. Sci. Phila., vol. xxi, pp. 7, 8. 

 Tretosphys uraeus Leidj-, 1869, Jour. Acad. Nat. Sci. Phila., -Snd ser., vol. vii, p. 435 



(mention only). 

 Priscodelphinus uraeus Cope, 1875, Proc. Amer. Philos. Soc, vol. xiv, p. 363. 

 Priscodelphinus uraeus Cope, 1890, Amer. Nat., vol. xxiv, p. 614. 



Description. — The species is founded upon a single lumbar from New 

 Jersey with which Cope associated a single caudal from the mouth of 

 the Patuxent river. The vertebrae are elongate as in the genus 



