NATURAL SCIENCES OF PHILADELPHIA. 21 



to bear a resemblance to those of CimoUasaurua, and were referred to an ani- 

 mal with the name of Brimosaurus grandia. Through comparison with the 

 skeleton of the Kansas saurian, they appear to be posterior cervicals, and 

 further appear sufficiently near in character to belong to the same, th< 

 tneir larger size renders it probable that they pertained to a larger species. 



A question arises as to the relationship of those remains originally referred 

 to CimoUasaurua with Discosaurus in the present state of our knowledge of tin- 

 latter. In the first place, by comparison with the skeleton of the Kansas 

 saurian, we observe that the position in the column, assigned to the vertebral 

 bodies of Cimoliaaaurua, was incorrect, and this probably contributed to mislead 

 Prof. Cope in his examination of the skeleton of the Kansas saurian. 



The vertebral specimens referred to Cimoliasaurus consisted of two sets of 

 specimens, from two different individuals, both from the green sand of Bur- 

 lington Co., N. J. They are described in "Cretaceous Reptiles," page 25, and 

 characteristic ones represented in plates v. and vi. 



The eleven vertebrae considered as lumbar, and represented by figs. 17-19, 

 pi. v, and 16-18, pi. vi, are evidently cervicals. Those considered as dorsals 

 on page 26, and represented in figs. 13-16, pi. v, are at least in part posterior 

 cervicals. Of the fourteen vertebras referred to on page 27 as dorsals and lum- 

 bars, those described and represented in figs. 1-5, pi. vi, are alone dorsals, while 

 the others described and represented in figs. 6-9 are posterior, and those of 

 figs. 10-18 more anterior cervicals. 



The cervicals of Cimoliasaurus are so different in their proportions from 

 those of the Kansas saurian that there can be no question as to the distinction 

 of the two animals, at least as species. 



Do all the remains originally referred to Discosaurus belong to this genus as 

 distinct from Cimoliasaurus ? I suspect that those from New Jersey belong to 

 the latter. The animals indicated by all the fossils which have been under 

 consideration are Plesiosauroid, and as in recognized species of Pleaioaaurus 

 there is much variability in the number, proportions, and other characters of 

 the cervicals without a corresponding extent of variation in other parts of the 

 vertebral column, we would be prepared to find in Cimoliasaurus nearly the 

 same kind of caudals as in Discosaurus. 



Prof. Cope, in his "Synopsis of the Ext. Batrachia and Reptilia," pt. i, 1869, 

 p. 56, describes two vertebral specimens from the lower bed of the cretaceous 

 green sand of Gloucester and Monmouth counties, which he attributes to a 

 species with the name of Elasmosaurus orientalis. The specimens described 

 as caudals are seen, by comparison with the Kansas skeleton, to be cervical-. 



The smaller of the two specimens is intermediate in its form, proportions, 

 and size with what appear to be the nearly corresponding vertebra; of the Kan- 

 sas saurian, and the vertebra; referred to Cimoliasaurus. The larger specimen 

 I have not seen, but from the description and measurements given it would 

 appear to have belonged to a species quite as large as the Kansas saurian. 

 The comparative measurements of the two specimens with that of the Kan- 

 sas saurian, which appears to be most like them, and witli the largest of the 

 specimens which had been referred to Cimoliasaurus, are as follow: 



New Jersey specimens. Kansas sp. Cimoliaiaurus. 



Length of body 3| in. 4^ in. 4} in. 3 in. 11/. 



Breadth " 4^ in. 5f in. 4J in. 4 in. 2 1. 



Depth " 3 in. 4 in. 3 in. 3J in. 



The various remains to which I have referred in this communication proba- 

 bly indicate a number of different species of a genus, presenting a like varia- 

 bility in the number and proportions of the cervicals as has been observed 

 in the closely related genus Pleaiosaurus. In the present condition of knowl- 

 edge of the remains, they appear to me to be referable to a series of spi 

 as follow : 



1. Discosaurus vetustus. 



Leidy: Pr. Ac. Nat. Sc. 1851, 326; Cret. Rept. United States, 1865, 22. 



1870.] 



