394 [August, 



other, as in the wolf, but nnore nearly equal in size and forming together more 

 of a triangle. 



Measurements. 

 Length of cranium from occipital condyle to the narrowest 

 portion of the former, which is just in advance of the 

 bifurcation of the sagittal crest 

 Breadth of cranium at most prominent part 



' " where narrowest 



Depth of lower jaw below last molar 

 Antero- posterior diameter of last lower molar 



" " penultimate lower molar 



" " ante-penultimate *< 



Transverse diameter of last upper molar 

 " " penultimate " 



** '< ante-penultimate molar 



1. Leptomeryx Evansi, Leidy. This is established upon 

 has lost the nose, and is broken at the parietal region. The specimen contains 

 upon one side all the molars, six in number, and upon the other side the posterior 

 four molars ; and it is accompanied by a portion of the lower jaw containing the 

 true molars and the last premolar. 



The genus is closely allied to the existing MoschuSf^LnA the species was about 

 the size of the M. Javavicus. The six superior molars form a closed 

 row, in advance of which a hiatus exists. The true molars are composed 

 of four lobes resembling those of recent musks, but they possess a peculiar 

 generic distinction, which is a tubercle rising out of the base antero-inter- 

 nally of the postero-internal lobe, about one-third the size of the lobes themselves, 

 and appearing as if it was a rudimentary fifth lobe. The third premolar consists 

 of two lobes as in the musks, and the anterior two premolars in section are tri- 

 lateral and consist of a broad external and a narrow internal lobe. 



The lower true molars are like those of the musks, but in the last of the series 

 the ordinary fifth lobe of ruminants is notched so that there are actually six lobes 

 to the tooth. The last premolar is worn in the specimen into a surface, resem- 

 bling in some degree the figure 3 in shape. In comparison with Moschns Javanicus 

 the forehead of Leptomeryx Evayisi has about the same inclination forward and 

 is almost as broad ; but the sagittal crest is longer and the temporal fossa? are 

 more horizontal and more capacious ; the orbits are smaller and more directed 

 upward; the zygoma is deeper ; the post orbital arch is more vertical, and, if 

 the specimen is a correct representative of the species, it is open for about a line ; 

 the glenoid articulation is more deeply concave, and it possesses a strong post 

 glenoid tubercle; the auditory bullas are much smaller; and finally the inion is 

 broader. 



Measiiremeyits . 

 Length from occipital condyles to first molar 2 in. 10 lines. 



Breadth at zygomata 2 



Length of upper molar series 1 



** series of lower true molars 



Transverse diameter of orbit 

 Vertical ' 



The species I have named in honor of its discoverer. Dr. John Evans. 

 Of turtles the collection contains numerous carapaces, which present such a 

 gradation of form, size and growth to the fivl species described in the " Ancient 

 Fauna of Nebraska," that I feel doubtful whether there is more than one species 

 among them, for all appear to me to be only different ages of Testndo lata, the 

 only one which was represented as full grown, as indicated by the sutural con- 

 nexion of the costal with the marginal plates. 



(The specimens upon which were established the new species and genera in this 

 communication were exhibited by Dr. Leidy to the members.) 



ELECTIONS. 



Dr. G. Emerson, of Philadelphia, was elected a Member, and the Rev. 

 Thomas G. Porter, of Lancaster, Pa., was elected a Correspondent. 



