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424 AMERICAN TESTUDINATA. Part II. 



■which give it a triangular form, in a front view. I shall describe this and the 

 other new species more fully elsewhere, and give accurate figures of all of them. 



GoNiocHELYS MINOR, Ag. The geographical range of this species is more exten- 

 sive than that of the preceding. I first found it in the neighborhood of Mobile ; 

 but received afterwards other specimens from Columbus, Georgia, through the kind- 

 ness of Dr. Gessner. Dr. Benedict also has sent me a specimen from New Orleans, 

 and Dr. Nott others from Mobile. This species differs from the preceding by its 

 smaller size, and more distinctly still by its arched sides, and the low keel of 

 the back. In both species the scales are edged with black, and black lines or 

 dots radiate from the posterior angle of the scales to their anterior and lower 

 margins ; but neither of them exliibits the characteristic stripes, which extend from 

 the eyes to the neck, in the genuine Ozothecas. 



II. OzoTHECA, A(j. The jaws and their muscles are by no means weak, but they 

 are not as strong as in Goniochelys. The alveolar surfaces are not as broad, 

 and the bones of the jaws not as thick, as in that genus, nor is the head as broad 

 across the muscles which move the jaw. The sides' of the head converge almost 

 constantly from the ear to the front end; and they arch pretty regularly from above 

 downward, back of the eye, and have no such sharp angles as there are in Gonio- 

 chelys. The outer surface of the jaw slants inward almost directly from the 

 orbit, and does not curve outward as far as in Goniochelys, if at all, so that the 

 bone there is not so thick as it is in this genus. About the front end, that 

 surface slants backward further than it slants inward at the sides, and the alve- 

 olar edge rises there. Thus the nose projects far over the end of the jaw ; and 

 this, together with the constant approach of the sides of the head forward, makes 

 the head very pointed in front. The jaw is never drawn down at the symphy- 

 sis to a point of any size. The vertical alveolar surface is high all round, 

 and is raised up somewhat under the nose ; but it is never, either here or in 

 Goniochelys, raised so high as in Cinosternoida3 proper. The horizontal alveolar 

 surface is not nearly as broad as in Goniochelys, and the space within its angle 

 is much larger. The lower jaw is not as thick as in Goniochelys. It is some- 

 what drawn outward and upward at the front end, not to a point, but to a curved 

 end ; its outer surface, at the sides, is nearly vertical ; at the front end it curves 

 far back, and this retreating part grows very broad downward. These latter char- 

 acteristics are not plain till the animal is full-grown. The alveolar surface is 

 not as broad as in Goniochelys ; and it widens constantly from each side of the 

 symphj'sis to the hind end. The ridge, spoken of as descending from the angle 

 on to this surface in Goniochelys, exists also in this genus, but is less prominent, 

 and is often merely a rising of the outer edge. The alveolar edges of both jaws 

 are shaqj, and the jaws are in every way well fitted for cutting. 



