3Y0 PROCEEDINGS OF THE NATIOXAL 2IUSEUM. vol. xxxvi. 



tunate enough to find that the remaining part of the shell and miuh 

 of the cliff had fallen, and were mixed in fragments with the earlier 

 debris. It became necessary, therefore, to carefully dig over all the 

 talus material, and to wash much of it also, in order to extract the 

 plates, which were generally separated. In this way many hundreds 

 were recovered, together with a few broken and badly disintegrated 

 A-ertebrae, ribs, and other bones, one piece only being in fair condition. 



A superficial examination of this material, which required several 

 daj'S' labor to bring away, led to the conclusion that the remains 

 probably belonged to a mammal resembling a Glyptodon, but later, 

 on comparing the plates and the best of the bones with the skeletons 

 of several turtles, it became clear that they represented an animal 

 closely related to the living Leatherback Turtle, though differing in 

 several respects. 



Dermal scutes of this same species had be^n previously picked up 

 from the beach bordering the cliffs by Dr. F. W. True, and later by 

 myself, but their true nature, though often commented on, was not 

 satisfactorily determined until the remains herein described were 

 found. 



PSEPHOPHORUS CALVERTENSIS, new species. 



Dcrmaforhclits. .T. :\Ii-i,LKK, Teher die fossilcn Keste der Zeuslodoutcu von 

 Xord-AiiuM-ika. 1S49, p. .34, pi. 27, fig. 7. Upper Eocene Zeuglodon 

 beds of Alabama. A fragment, evidently of the plastron, comprising 

 13 scutes and jiarts of scutes. 



Type-spenmen.—C-Ai. Xo. ()059, U.S.N.M. (Catalogue of Fossil Ver- 

 tebrates). A fev.- bones and numerous scutes of the carapace and 

 plastron, many joined together, collected in July, 1908, 2 miles south 

 of Chesapeake Beach, in the Calvert Cliff's, Calvert County, Mary- 

 land, by AA^illiam Palmer and David B. Mackie. From the top of 

 the lower stratum of a Middle Miocene cliff'. 



Carapace composed of numerous, thick, bony scutes, mostly large; 

 slightly, or not at all, sculptured on the dorsal surface, and generally 

 longer than broad. One strong and prominent median, straight, 

 longitudinal ridge, and several, perhaps six, minor parallel ridges, or 

 thickenings of the scutes. Minor ridges but slightly raised above the 

 adjoining scutes and seemingly decreasing in height according to 

 their distance from the more pronounced median ridge. Scutes of 

 the ridges aV)()ut twice as long as wide, the ridge-slopes covering the 

 whole surface of the scutes and extending over adjoining ones; not 

 confined to the central portion of the ridge-scutes as in P. poh/gonux 

 and />. coridced. Transverse sutures generally narrower than the 

 longitudinal sutin-es, and sometimes anchylo.sed. Plates usually very 

 close-fitting below, almost or quite anchylosed. Under surface quite 

 uneven, having somewhat the appearance of wet clay which has been 



