AND AVES OF NORTH AMERICA. 



195 



This ridge is the external distal longitudinal of the other speoies, very muoh developed. In M. oarthrus it is separated 

 by considerable interval from the median posterior; in M. dekayi it just attains it; here, it extends along the side of 

 and in front of it, to the rugose area in front of the pit. Its prominence produces a produced external posterior angle 

 on the distal articular extremity. The median posterior is much prolonged downwards, and is very rugose; a ridge is 

 also oontinued from the knob to near the distal artioular extremity, and its line is the point of convergence for two 

 scries of strong rugse. The anterior inner ridge is strongly pronounced. 



The general size of this species is not more than hall' that of M. dekayi. 



The supposed humerus has a Battened shaft, becoming more cylindrio proxtmally. It looks as though it had 

 been used by Indians as a pestle. 



In. 



Length posterior dorsal, ;j 



Depth cup " " 2 



Width " " " 2 



Length of os quadratum, 4 



Width of dorsal rib, 



From knob to external angular quadrate, 2 



Diameter proximal extremity, (average) 



" transverse, of body at, knob, 

 " distal extremity, 



Lin. 



8.8 



3. 



4.8 



8 



8.5 

 11. (i 

 11 



19.2 

 11. 



MOSASAURTJS MISSURIENSIS, Harlan. 



Ichthyosaurus do., Harlan, Trans. Amer. Philos. Soc, IV, 405, Tab. XX, 1884 Batrachiosaurus, Harlan. Ba- 

 traohiotherium, Harlan. tMosasaurus neovidii, Meyer. ?M. maximiliani, Goldfuss. M. rnmuriemu, Leidy, Cretac, 

 Rept. VII, p. 15, 16, 17, 18. 



The centra, of the veiiebnc of this species are moderately depressed. The centra of the caudals, posterior to I he 

 disappearance of the diapophyses, areas wide as deep, and of nearly similar Length, and with anchylosed chevron 

 bones. A line cranium is figured by Goldfuss, and he shows the crowns of the teeth to be suboylindric, incurved ami 

 facetted. 



An unusually perfect specimen of this species, or one allied to it, was recently exhumed by W. E. Webb near 

 the town of Topcka in Kansas. My friend, Prof. .1. Parker, of Lincoln College, of that place, informs me that it is 

 seventy-live feel, in length, and the gentleman who discovered it, that, it, measures eighty feet. Its mandibular rami 

 are stated by the same person to measure five feet. Measurements of the vertebrae indicate them to be of a, size quite 



similar to those; of large individuals which have been discovered in flic green sand of New Jersey. They measure as 

 follows, as stated on photographs by my friend, W. E. Webb. 



Inches. 

 Diameter oervicals centra, only, 2.5 



dorsals, with diapophyses, 7 



" lumbars, 2 



These proportions illustrate again the Ophidian or eel-like form of this genus, and the relatively large size of the 

 bead. 



The teeth resemble ill size those of large specimens of M, dekayi. 



The following eonveUons. should be made in the nomenclature adopted by Goldfuss in the explanations of his 

 plate, Nova, Ada,. Nat. Our., 1855, Tab. VI to XI. 



Tab. VL 

 T. is Squamosal, called temporal. 



T. in. is Opisthotic, " temporo-mastoid. 



T. p. is 1'roofic and Epiotic. 



P. is a, thin lamina of parietal prolonged backwards over supraoccipital. 



Tab. XI. 

 2 ':' ? said to be pubis. 



il is Quadratum, " " Olecranon. 



Prom the upper cretaceous of middle North America. 



