KAENIDJE. 



79 



The course of the parietofrontal suture is different from that ot Chisternon hebraicum, since 

 mesially it is placed further forward and runs outward and somewhat backward to the orbit. 

 The upper surface of the skull appears to have been covered with horny scutes. 



All of the cervical vertebrae are present, except the first. The whole series had a length of 

 close to ioo mm., not quite one-third the length of the carapace. All have transverse processes. 

 All have a sharp crest on the lower side of the centrum. These crests are so deep that they 

 would have interfered greatly with any considerable flexure of the neck in a perpendicular 

 plane. The second centrum is flat anteriorly, very concave posteriorly. The third is moder- 

 ately convex in front, deeply concave behind. The fourth has the anterior end concave in the 

 center, but the concavity is surrounded by a broad convex wall. The hinder end is shallowly 

 concave. The fifth is rather deeply concave in front, flat behind. From the outside of one of 

 the postzygapophyses to that of the other of the vertebra is 13 mm. The centrum of the sixth 

 cervical is concave in front. The form of the hinder end can not be observed. The front of 

 the seventh is concave, the hinder end flat. The eighth is concave in front; the hinder end is 

 quite convex, but small. The first dorsal has a large concavity to receive the convex surface 

 of the eighth cervical. This concavity looks directly forward, as in the Pleurodira, not down- 

 ward as in the Cryptodira. This is another indication that the head and neck were not 

 retracted within the shell. In the hindermost of the cervicals the zygapophyses stand high 

 above the centra. Furthermore, the ends of the centra, especially when they are flat or 

 convex, are considerably higher than wide. Both these conditions would be unfavorable to 

 the flexure of the neck in a perpendicular plane. The postzygapophyses of the last cervical 

 and the prezygapophyses of the first dorsal are short, not long and curved like those of the 

 Cryptodira. On the other hand, the lateral motion of the neck could hardly have been so free 

 as in the Pleurodira; and there was no projecting roof of the carapace under which the head 

 could be concealed. We must conclude that these turtles could protect their heads hardly more 

 than the sea-turtles. 



The ascending portion ot the scapula (fig. 61 ) is long and slender; as is also the precoracoid 

 process. The coracoids (fig. 62) are somewhat damaged; but it is evident that the median end 

 was not greatly expanded, not so much as in some Emydidae. The humerus (figs. 63, 64) is 

 67 mm. long. The shaft is little bent. The distance from the outside of the radial process to the 

 outside of the ulnar is 27 mm. The breadth of the distal end is 21 mm. The ectepicondylar 

 foramen is situated 9 mm. above the condyle. The humerus is slightly longer in propor- 

 tion to the length of the carapace than in Graptemys, but not so long as in Chelydra. The 

 ulnar process does not extend so far above the head as in Chelydra. The remainder of the 

 fore limb is missing. 



The pelvis is badly crusht, but there appear to be no striking differences between it and that 

 of Chisternon hebraicum (figs. 85, 86). The ossified prepubic process is long, and it resembles 

 that of the species just mentioned. The femur (figs. 65, 66) is 68 mm. long and moderately bent. 

 In proportion to the length of the carapace the femur is shorter than that of Graptemys and 

 still shorter than that of Chelydra. The tibia and the fibula (fig. 66) are each 53 mm. long. 

 The tarsal bones and some of the metatarsals are preserved. The second metatarsal is 21.5 

 mm. long. This appears to indicate a rather long foot. 



The tail was long. Eleven of the vertebras are preserved, having a length of 143 mm.; 

 and there were evidently several more. So far as determinable, they were convexo-concave. All 

 probably bore chevron bones. Some of the anterior caudals have, in the position of the neural 

 spine, a rounded boss, as if for the support of a distinct bone, such as occurs on some of the 

 caudals of Chelydra. 



The specimen figured and described by Cope (Vert. Ten. Form. West., p. 148, pi. xvii. 

 figs. 1, 2} as Ba'ena arenosa is now in the American Museum of Natural History and has the 

 catalog number 1 1 12. Cope's figures are one-fourth the size of nature and are inverted. His 

 measurements are in some cases erroneous. The carapace is 320 mm. long, instead of 450 mm. 

 The carapace is somewhat crusht and its transverse diameter was nearer 260 mm. than 240 mm. 

 The length of the plastron is 290 mm. The anterior lobe is 82 mm. long; the posterior lobe 

 87 mm. The width of the base of the anterior lobe is 102 mm.; that of the base of the posterior 

 lobe, 116 mm. The width of the anterior at the gulo-humeral sulci is 71 mm.; that of the 



