566 



CHELONIA. 



side, nine lines of hiatus remains anterior to the first molar, below which the 

 surface is depressed for the better accommodation of the superior canine. 



The first molar has three lobes : an anterior and a posterior rounded talon, and a 

 middle, compressed conoidal cusp. The former are nearly equal in size and the 

 latter is a little larger. 



The second molar is relatively longer than that of Felis. It also has three 

 lobes, the anterior of which is relatively broader than that of M. neogaBus, and is 

 nearly equal to the posterior, which is notched at summit. The middle lobe is 

 long conoidal compressed. 



The inferior carnassial tooth is relatively broader than that of M. neogaBus, and 

 is more complex in its form from the presence of an additional lobe to that already 

 existing in excess in this species, beyond what it is in Felis. 



ADMEASUREMENTS. 



Inches. Lines. 



Length from occipital condyle to superior incisive alveoli, . 6} 



Breadth above the superior carnassial tooth, . ... 3 



" at canine alveoli, ..... 2 



Antero-postcrior diameter of superior carnassial tooth, ... 10 



DESCRIPTIONS OF CHELONIA. 



TESTUDO. Linncms. 



In Dr. Owen's collection of fossil remains from Nebraska, there are four species 

 of Turtles, belonging to the genus Testudo. 



The carapace of the latter is composed ordinarily of ten vertebral plates, eight 

 pairs of costal plates, and eleven marginal plates each side of the nuchal and 

 pygal plate. 



The first vertebral plate is quadrilateral, with convex sides, and long and narrow. 



The succeeding plates to the penultimate are most frequently hexahedral. 



The penultimate plate is inverted V-shaped, and the last is rhomboidal, and 

 received between the preceding and the pygal plate. The costal plates are alter- 

 nately broad and narrow. 



The carapace is also invested by five vertebral scutes, four pairs of costal scutes, 

 and eleven marginal scutes, each side of a narrow nuchal, and a broad undivided 

 pygal scute. 



The sternum is composed of an entosternal plate, and four pairs of lateral plates, 

 invested by eight pairs of lateral scutes, including those supplementary to the 

 axillary and inguinal notches. 



All the specimens of fossil Turtles above referred to, belonged to immature indi- 

 viduals, as the costal plates were still united by cartilage to the marginal plates 

 when the animal died. 



