•8 Field Columbian Museum — Geology, Vol. II. 



This genus was based s upon vertebral centra alone, from the 

 ■cervical, dorsal and caudal regions: the author, however, referred 

 them all erroneously to the dorsal and lumbar regions. The type is 

 well figured in Leidy's work on Cretaceous Reptiles, plates v and vi. 

 The vertebrae have infracentral vascular foramina. The ribs are 

 single-headed. The largest centrum measures no millimeters in 

 the greatest diameter. This genus has served as a sort of waste 

 basket for the reception of fragments and poorly known forms. C, 

 snotvii is known from a skull and long neck. It can scarcely belong 

 i n Cimoliasaitrus. 



DISCOSAURUS. 

 Leidy, Proc. Acad. Nat. Sci. Phil. 185 1, 326 (1852). 



i'Lanior Leidy, Proc. Acad. Nat. Sci. Phil. 1870, 20, 22; Cope, Cretac. 

 Vert. 1875, 255 (Cimoliasaitrus). — Cretaceous, Mississippi. 



Discosai/rus vetustus Leidy, Cretac. Reptilia, 23, pi. 5, ff. 10-12. 



vetustus Leidy, Cretac. Reptilia, 22, pi. iv, ff. 13-18, pi. v, ff. 1-9; 

 Proc. Acad. Nat. Sci. Phil. 1851, 326; Cope, Ext. Batrachia 

 etc. 256; Amer. Journ. Sci. 1870, 141; Cretac. Vert. 1875, 

 255 (Cimoliasaurus). — Cretaceous, Alabama. 



This genus was based upon the mutilated bodies of two caudal 

 vertebrae from the Cretaceous of Alabama. Leidy associated with 

 these other mutilated vertebrae from the Cretaceous of Mississippi, 

 New Jersey and Alabama. Cope suppressed the name, as of a genus 

 insufficiently differentiated from Cimoliasaiirits. This is quite true, as 

 it is also true of several of Cope's own genera of the plesiosaurs. It 

 is not at all improbable, however, that there are different species, and 

 perhaps different genera represented by the specimens Leidy described 

 and figured. 



BRIMOSAURUS. 

 Leidy, Proc. Acad. Nat. Sci. Phil. 1854, 73. 



<;randls Leidy, Proc. Acad. Nat. Sci. Phil. 1854, 73, pi. i, ff. 1-3; 

 ibid. 1870, 10; ibid. 1871, 22 (Discosauri/s); Cope, Ext. 

 Batrachia, etc. 1869, \7,,^(Cii/io/iasauri/s); Proc. Bost. Soc. 

 Nat. Hist. 1869, 266 (id.)', Amer. Journ. Sci. 1870, 269 (id.), 

 Rep, Geol. Surv. Terr. 1871, 400 (id.)', Cretac. Vert. 1875, 

 2 55 ( l 'd.) — Cretaceous, Arkansas. 



Tins genus and species were founded upon more or less imperfect 



