Cope.] 264 [January 20. 



tebrjB indicate them to be of a size quite similar to those of large 

 individuals which have been discovered in the Green-sand of New 

 Jersey. They measure as follows, as stated on photographs by my 

 friend, W. E. Webb. 



Diameter. 



Cervicals, centra only 2.5 inches. 



Dorsals, with diapophyses 7 " 



Lumbars 2 " 



These proportions illustrate again the ophidian form of this genus, 

 and the relatively large size of the head. 



The teeth resemble in size those of large specimens of M. JSHtcliillii. 



A cranium of this species has been figured by Goldfuss of Bonn. 



The following corrections should, be made in the nomenclature 

 adopted by him in the explanations of his plate, Nova Acta Nat 

 Cur., 1845, tab. vi to ix. 



TAB. VI. 



T. is squamosal, called temporal. 

 T. m. is opisthotic called temporo-mastoid. 

 r. p. is prootic and ejiiotic. 



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

 supraoccipital. 



TAB. IX. 



2 ? ? said to be pubis. 



3 is quadratum, said to be olecranon. 



From the upper cretaceous of Middle North America. 



Mosasaurus Brumby i Gibbes. A mpJiorosteus Bmmbi/i G'lhhes. 

 Smithsonian Contrib. to Knowledge, II, 9, Tab. iii, 10-16. 



This species appears to be common in the rotten limestone of 

 Georgia and Alabama. Further description in MS. wiU be published 

 hereafter. 



Mosasaurus minor Gibbes. Loc. cit. 7 Tab. i, 3-5. 



This small species appears not to have been so large as the Clidas- 

 tes if/tianauus Cope. 



The cretaceous of Alabama. 



Platecarpus Cope. (From niuTtj, an oar.) 

 This genus is especially characterized by the peculiar insertion of 

 the pterygoid teeth. Its humerus also is more chelonian than that 

 of Mosasaurus, while the os quadratum presents marked diflerences. 



