24 mm. 



27 mm. 



34 mm 



40 " 



37 " 



46 '• 



INSTITUTE OF SCIENCE, PHILADELPHIA. 2/ 



Three dermal bones of greater length than breadth are variably curved 

 conical, and have a thick base. That represented in figs. lo, ii, plate III., 

 is nearly straight and has its base nearly flat. In another, about the same 

 size, the cone is most curved and pointed, and the base is thick and convex. 

 In the remaining and largest specimen, the cone is more pyramidal and the 

 base thicker and convex. It is hollow and contains a nucleus which rattles 

 when the specimen is shaken. The measurements of the specimens are as 

 follows : 



Breadth of base, ..... 

 Height of cone, .... 



A more enigmatic specimen than the conical dermal bones above de- 

 scribed is the one represented in figures 7, 8, plate IV. It has a thick, 

 elongated hexagonal basis, from which spring two unequal conical tubercles 

 separated by a valley, divided by a grooved ridge. The measurements of 

 the specimen are as follows : 



Length of the bone, .... 

 Thickness of the base, ... 

 Breadth opposite the larger tubercle, . 

 Breadth opposite the smaller tubercle. 

 Height at the larger tubercle. 

 Height at the smaller tubercle, 



8. Among the Peace Creek fossils occurs a single bone of the Megalo- 

 nyx Jeffersonii, a first phalanx, like that represented in figures 3, 7, plate X., 

 of " A Memoir on the Extinct Sloth Tribe of North America." The length 

 of the specimen is 30 mm., its depth 52 mm., and its breadth 32 mm. 



9. Fragments of ribs of a Manatee, Manattis antiquiis. 



10. Half a dozen vertebrae and several teeth of several Cetacea of the 

 family of the Dolphins ; undetermined. 



11. Remains of several species of Emyds, consisting of fragments of 

 the carapace and plastron. Among them the only specimen sufficiently 

 characteristic for determination is the nuchal plate represented in fig. i, 

 plate IV. It is remarkable for its deeply sculptured condition, greatly ex- 

 ceeding in this respect the corresponding bone in our known recent species 

 of Emys. The areas defining the scutes which impress the plate are deeply 

 cut and are crossed by prominent ridges separated by deep furrows. The 

 fossil probably indicates an extinct species, for which the name of Emys 

 euglypha* has been proposed. The measurements of the specimen are as 

 follows : 



* Proc. Acad. Nat. Sc, 1889, 97. 



59 



mm 



II 





30 





24 





32 





30 





