07 



mentoiis insertion is well developed. The distal extremity is slightly 

 widened, and its articular surface is wedge-shaped with very convex base. 

 Its surface is slightly concave in both directions, and without median ridge. 

 The margin of the shaft terminates in a short tuberosity bearing articular 

 surface. Transverse diameter, 16 lines; length of shaft preserved, but in- 

 complete, 9 inches 1 line. 



This is possibly the species originally described by Marsh as P. owenii, 

 a name which could not be used on account of its pre-occupation for another 

 species from England. It was described by the writer in 1872 under the 

 name of P. harpyia; but, a fire occurring in the establishment printing the 

 paper, its publication was delayed until two days atler Professor Marsh had 

 republished his species as P. occidentalis. 



The type-specimens of the two species described were procured from 

 the bluifs of Butte Creek south of Fort Wallace, Western Kansas. 



Order I.— CROCODILIA. 



Only two species of this order are known from the Cretaceous formations 

 west of the Missouri River : the one from the lead-colored stratum of the 

 Benton epoch, or No. 2, in Kansas; the other from the Fort Union group, or 

 No. 6, of Colorado. The latter is a short-headed species, allied to, and near 

 the size of, the alligator of Louisiana. The former is a Hyposaurus, of eight 

 or ten feet in length, found in digging a well at Brookville, and presented to me 

 by my friend Dr. William E. Webb, of Topeka. The individual discovered 

 was not fully grown, but indicates a smaller and stouter crocodile than the H. 

 rogersii, Owen, of the New Jersey greensand. This genus belongs to the 

 group witili sul)biconcave vertebrae, and had a long, subcylindric snout. 



HYPOSAURUS, Owen. 



Hyposaurus vebbif. Cope. 



An anterior cervical vertebra presents the following characteristics. It 

 is that one in which the parapophysis occupies a position opposite the lower 

 third of the vertical diameter. Its centrum is stout in form; the articular faces 

 but little concave; the posterior a little more so than the anterior. The ante- 

 rior is almost regularly hexagonal; the posterior subround, a little deeper than 

 wide. The inferior surface po.'sses.ses a strong, obtuse, median carina, wiiich 



