52 



FOSSIL TURTLES OF NORTH AMERICA. 



correct when lie states that it did not come in contact in the midline with the ischium. The 

 pelvis in the specimen here described has probably suffered some antero-posterior crushing, 

 but the pubes and ilia do join. In Baena, whose pelvis is identical with that of Glyptops, 

 there is, at least in aged individuals, a union of these elements in the midline. 



The lateral pubic processes are quite different from those of Chelydra, being more massive. 

 At their extremities, where they come into contact with the xiphiplastra, they are enlarged and 

 rough. Above this they are constricted into a sort of neck. The ischium is narrow from front 

 to back, about 12 mm., and thin, as in Baena. Its hinder lower border is nearly straight until 

 the processes are reacht on which the ischium rests on the plastron. These processes stand 

 at a distance of 30 mm. apart. Each is terete, pointed at its free end, and about 15 mm. long. 

 They are directed backward. 



The ilium is not greatly different from that of Chelydra, except that it is shorter and 

 proportionately stouter. The sacrum is in general smaller and weaker than that of Chelydra, 

 except that the distance of the acetabula apart is the same. The pelvis is essentially like that 

 of Baena and all parts should be compared with those of the latter genus. 



The only portion of the hind limb present is the right femur and probably some foot bones. 

 Dr. Baur states that the femur agrees with that of the Emydidae. In length, it is exactly that 

 of the Trachemys mentioned and relatively much shorter than that of Chelydra. It is much 

 curved, especially toward the distal end (figs. 25, 26). The greater trochanter is separated 

 from the lesser by a deep fossa. From the greater trochanter a prominent crest runs down 

 on the hinder side of the femur one-third or more of its length. The distal end of the femur is 

 damaged, but it presents indications of having had the condyles more prominently developt 

 than in turtles in general. The total length of the femur in a straight line is 61 mm. 



One complete toe, which probably belonged to a hind foot, is preserved with the parts in 

 place (fig. 27). It shows a metatarsal and three phalanges, and these have a total length of 42 

 mm. The metatarsal is slender and has a length of 22 mm. 







Figs. 28-31. Glyptops ceelatus. Type specimen in U. S. N. M. 



28. Portions of first and second peripherals and 



first costal. XJ. 

 19. Section across second peripheral. X- 



30. Section across hinder peripheral. 



31. Proximal end of costal bone, showing scute 



areas and sculpture. X. 



Glyptops caelatus sp. nov. 

 Plate 7, figs. 1,2; text-figs. 2831. 



1 he fragments oi tortoise to which this name is given were collected by Mr. J. B. Hatcher, 

 in 1887. ar Muirkirk, Maryland, in deposits belonging to the Potomac formation of the Lower 

 Cretaceous. The fragments consist of portions of costals and of peripherals. The most 

 important fragment consists of the right first costal, a part of the first and most of the second 

 peripherals. There is also a part of a costal situated further back in the carapace. These 

 bear the number 1930, and belonged doubtless to one individual. There is present also a 

 hinder peripheral and a first right peripheral which have the number 1930. There are also 

 two fragments of costals of a young individual, one of which shows the rib-head. The bones 

 bearing the number 1930 are regarded as being the type of this species. All the specimens 

 are in the United States National Museum. 



