1851.] 327 



dedicate to the memory of Harlan, under the name of Priscodelphinus Haklani, 

 Leidy , 



In the collection of the Academy there are preserved two caudal vertebrae of a 

 young cetacean, from the Green Sand of Jersey. These specimens are larger 

 than the dorsal vertebra just described, but from the length of their bodies, and 

 the width antero-posteriorly of the neural arch, I suspect them to belong to the 

 same genus of the latter, but a larger species, for which I propose the name 

 Pkiscodelphinus gkandjEvus, Leidy. 



Measurements of the posterior dorsal vertebra of P, Harlani. 

 Length of body, ..... 2 inches. 



Breadth of articular surfaces, . . . 8 lines. 



Length of transverse process, , . . li Inches. 



Measurements of two caudal vertebra: of P. grandcsvus . 

 Length of body, ..... 21 inches. 



Breadth of epiphysial surfaces, . . . 2i <' 



The two species of Priscodelphinus possess more than ordinary interest, from 

 their being the first mammalia which have been discovered in the cretaceous 

 formations. 



Crocodihts fastigiatus, Lcidy. Established upon a tooth which Mr. T. 

 Conrad informed me was obtained by Mr. Smiley from the Eocene formation of 

 Virginia. The specimen is about the size of that of Crocodilus champsoides, 

 Owen, represented in fig. 11, tab. v,, of the Monograph of the fossil Reptilia of 

 the London Clay by Prof. Owen. The crown has about the same length as in 

 the last mentioned species, but is more robust, more curved and pointed, with 

 more numerous ridges but not so coarse, and between the larger are from one to 

 four fine corrugated linear ridges. The fang is also a little more robust. The 

 enamel is jet black, shining. The osteo-dentine is thick, dark brown with a 

 resinous lustre. 



MeasJiremefits. 

 Length of crown, ..... 9 lines. 



Diameter at base, . . . . . 4 " 



Dr. L. further called the attention of the members to some very remarkable 

 fossil remains of mammalia from Nebraska, belonging to the collection of Dr. 

 D. D. Owen. 



The fossils consisted of a nearly entire cranium of Rhinoceros occidentalis, two 

 crania of Oreodon priscum,a large portion of the face of Arcbaeotherium Mortoni, 

 which has true molars resembling those of Chocropotamus and Hyracotherium, 

 and a very perfect turtle, which vi'as characterized as follows. 



Emys Oweni, Leidy. Approaches the genus Testudo in many of its characters. 

 Carapace very convex ; marginal plates nearly vertical ; costal plates alternately 

 broad and narrow. There are nine vertebral, nine costal, and eleven marginal 

 plates each side of the pygal and nuchal. 



Straight. Curve. 



Length of Carapace, . . 11 inches. 13 inches. 



Breadth . . 8J " 14 " 



Heighth . . 5i 



