274 



FOSSIL TURTLES OF NORTH AMERICA. 



341. 



The choanae are far forward. The roof of the mouth in front is vaulted, not greatly unlike 

 that of a Testudo. The vomer apparently extended between the palatines to the pterygoids 

 or very close to them. The distance across the palatines, at their hinder ends, is 20 mm. 

 The distance across the constricted portion of the pterygoids is 13 mm. There are posterior 

 palatine foramina. The lower jaw, as shown by the American Museum specimen, had a 

 single sharp cutting-edge, which workt against that of the upper jaw. The lower jaw appears 

 to have formed a beak in front. The symphysis is short, about 12 mm. in length. The jaw is 

 20 mm. high at the coronoid region. 



The right humerus is present in the Yale specimen, and complete except that the radial 

 tuberosity is broken off. The length from the proximal surface of the head to the distal end 

 is 83 mm. The greatest diameter of the head is 21 mm. The ulnar tuberosity is as large as 

 that of Chelydra. The angle between the two tuberosities is nearly the same as in Chelydra. 

 The ectepicondylar foramen also resembles that of the genus just named. The distal articular 

 surface appears to have been bent toward the palmar surface more than in Chelydra. The ulna 

 is like that of Chelydra, but is, relatively to the length of the humerus, longer than in the genus 

 named. It is likewise thicker from the dorsal to the palmar surface. The length is 55 mm.; 

 the least breadth, 8 mm. The distal end is 19 mm. wide. The dorsal surface is strongly 

 markt by ridges for the attachment of muscles. About two-thirds of the radius is preserved. 

 Some portions of the hinder limbs are preserved, wholly or partly; but they have not been 

 completely removed from the matrix. The right astragalo-calcaneum was found in the right 

 axillary notch. It resembles that of Chelydra, but has the fibulare co-ossified with it. 



The vertebra are represented by portions of two cervicals, but they furnish us little 

 information. One lies against the head of the humerus and presents a cup-shaped articular 



cavity. The centrum is 19 mm. wide, 

 and there is a sharp median carina on 

 its lower surface. One complete toe 

 is present (fig. 339). It was found in 

 the right axillary notch; but from the 

 length of the phalanges and the fact 

 that the right astragalo-calcaneum 

 was found close to it, it is concluded 

 that it is one of the digits of the hin- 

 der limb. 



No. 5934 of the American Muse- 

 um furnishes some fragments of the 

 cervical vertebrae- One of these, a 

 posterior one, shows that on the under 

 side of the centrum there was a sharp 

 and prominent carina. The anterior 

 end of the centrum has right and left articular cavities. A posterior caudal has the centrum 

 17 mm. long. The total height of the centrum and the arches is 23 mm. The centrum is 

 procoelous. The ulna is represented by fig. 340. It resembles that of Chelydra, but it is rela- 

 tively broader and the radial border is thicker. Fig. 341 represents an ungual phalanx and 

 the one preceding it. A considerable portion of the pelvis is preserved (figs. 342, 343). The 

 upper end of the ilium is missing, but it was probably not broadened. On its anterior border, 

 half the height above the acetabulum, is a strong process directed outward and forward. The 

 pelvis resembles that of Testudo. The ischial symphysis is 13 mm. thick. There is a long 

 antero-lateral pubic process. The pubic symphysis was more than 23 mm. long. 



Dr. Leidy's second specimen, in the U. S. National Museum, furnishes the right scapula. 

 This is represented as seen from behind and of two-thirds the natural size by fig. 344. The 

 height of the body above the glenoid fossa is 102 mm; the proscapular process is 54 mm. long. 

 Professor Cope described from Ham's Fork, Wyoming, a species which received the name 

 Baena ponderosa. The specimens are now in the U. S. National Museum, at Washington, 

 where the writer has twice examined them. Cope states that his figures are three-fifths the 

 size of nature; but the measurements show that they are only half that size. Cope's fig. 5 

 represents the first and second right peripherals. The suture between the two is not well 



FlGS. 339-341. Baptemys wyomingensis. Limb bones. 



339. Digit belonging to specimen of fig. 338. Xl. 



340. Ulna. X. No. 5934 A.M. N.H. 



341. Terminal and penultimate phalanges. X. No. 5934 A. M. N. H. 



