42 



THE EXTINCT BATRACHIA, KEPTILIA 



with powerful propelling flippers. The preceding cut illustrates its form and size in rela- 

 tion to the posterior dorsals from nearly the same position in the C. magnus and Elasmo- 

 saurus platyurus. 



The general characters of the cervical and dorsal series arc very similar to those of 

 Elasmosaurus, but they all exhibit considerably larger neural canals. In the immature 

 individual, the neural arch of the dorsal vertebra; is not coossificd, but is separated by 

 suture as in Plesiosaurus. 



That there arc; several species of this genus is suggested by Lcidy, and seems probable 

 to the writer. As one of these has been already named, the characters of those which 

 appear distinct may be pointed out. 



Anterior caudals, articular faces with rounded margins ; antero-posterior diameter 

 greater, 2 in., width, 2 in. 7 1. Pit of diapophysis 1 in. 3 1. 



0. VETUSTUS. 



Anterior caudals, articular faces with acute marginal angle, antero-posteriorly shorter 

 1 in. 7 1. by 2 in. (> 1. in width; pit 111. Cervical with straight sides and broader form ; 

 width 31.2 1. by 24.5 long, the ^diapophysis narrow and stout. 



0. MAGNUS. 



Anterior dorsals sborter and higher than in C. magnus, the posterior cervicals, there- 

 fore shorter than in the same ; diapophysis of first dorsal longer. 



0. (J KAN I) IS. 



Posterior cervical with neural canal as large as C. magnus, but centrum four times as 

 large, and a strong longitudinal ridge half way between pleurapophysis and neural arch, 

 giving pentagonal section: 45 1. long by 52 1. wide; hence longer. 



E. OKIENTALTS. 



CIMOLIASAURUS VETUSTUS, Leidy. 



JJucosaurus Leidy, Proc Acad. N. Bci., 1851, :j2(i. Cretaceous Reptiles, N. A., 22. I'ledosaurux, DeKay Ann. 

 Lye, N. Y., 1838, 185, Tab. 



If the vertebra from Alabama from Jos. Jones, described by Leidy in the Cretaceous 

 Reptiles as No. 1, are typical of this species, they present certain peculiarities which distin- 

 guish them from those of an individual of C. magnus which I describe below ; perhaps 

 the species are distinct. 



Cretaceous Alabama,? Mississippi and ? New Jersey. 



