AND AYES OF NORTH AMERICA. 



235 



This species, the largest of the genus, is found in the upper green sand bed of the upper Cretaceous of New Jer- 

 sey. The specimen from which the above description was taken, was found by my Wend I. C. Voorhees. 



Puppigerus, Cope. 

 Genus novum Cheloniidarum. 



Xiphisternal bones united throughout their length with eaoh other by suture; otherwise as in Ohelone. 



This genus embraces the Eocene marine turtles of the London clay, and a Miocene species of North America. The 

 difference in the structure of the xiphisternal is very material, especially in view Of its significant relationships to the 

 same portion in various other genera of marine turtles. 



The Ohelone gramkevus, Leidy, from the Miocene of Shiloh, N. Jersey, belongs to it. Portions of the sternum 

 display a higher degree of ossification than in Ohelone, thehyo- and hyposternal having a very extensive union, greatly 

 restricting the median and lateral fontanels. This character In the Eocene forms is coincident with the extensive 



union of xiphisfcrnals, and I do not doubt but that that character belongs to the 0. grandavus also. The species of 



the genus will be: 



Miocene N. Jersey. Puppigerus subcristatus, Ow. & Hell, Eocene England. 



Puppigerus grandsevus, Leidy, 



longioeps, 

 breviceps, 



convexus, 

 latiscutatus, 



Ow. & Bell, Eocene England. 



subca.rina.tus, 



crassicostatus, 



? parviscutum, Cope, 



N. Jersey. 



Osteopygis, Cope. 



In the out Of a restoration of this genus on page 188, ten costal bones are represented; this is an error, as the true 

 number is nine, the last marginal bone not having any costal hone corresponding to it, as in most other genera, but 

 being united, like the pygal or median, with the large last vertebral bone-. Therefore, the suture appearing to bound 

 such a costal posteriorly must be erased from the cut, though it may have existed in a fetal condition of the genus. 

 The posterior small vertebral must also be erased. The line dividing the large median bone transversely, represents 

 what may be a coiissilied suture on the specimen, but may not be such. 



In this genus the penultimate marginal on each Side is known, and exhibits a, costal articulation. This marginal 

 is the one omitted from such connection in the Oheloniid®, Emydidas, etc. The additional costal in this genus (eight being 

 the number in the order generally) is the anterior, which is articulated to the second instead of the third marginal. 



The figure (89) of the restoration of the carapace of Propleura correctly represents ten costal bones, as I deter- 

 mine by a reexamination of the typical specimen described in the text. This genus and the last I propose to regard 

 as representing a peculiar- family of the Amyd.e or Oryptodira, to be called the PbOPLEUBID^. I suspect that Oata- 

 pleura will also enter it, but whether it has ten ribs or nine I cannot tell. It probably possesses the extra posterior of 

 Propleura, but whether the tenth or anterior is uncertain, as it lacks the pit of the marginal bone. As regards Lyto- 

 loina, T can at present give no opinion. 



In addition to the characters derived from the carapace, those already adduced (p. 181) as distinguishing this 

 family from the ( !heloniid», may be added. These arc: the humerus with two proximal crests at right angles to each 

 other, diverging from the extremities of the condyles; shaft flattened, slightly curved. Femur with similar trochan- 

 teric crests largely developed; shank very slender, gently curved, extremity dilated". Form exactly as in Chelydra. 



The peculiar relationships of this group were first pointed out by the writer, in Proceed. Acad. Nat. So., 1868, 



S85; and Proceed. Amer. Phil. Roc, 1800, 10. 



PTTHOKOMORPHA. 



Mosasaurus, Conyb. 

 Mosasaurun dekayi, Bronn. 



A line specimen of this species was recently exhumed near Mullica Hill, N. Jersey, and submitted to me for ex- 

 amination by the owners. The muzzle is like that figured in profile by Leidy, in Cretaceous Kept. N. America, PI. 

 XIX, lig. 6; and the quadrate, pterygoids, atlas and suspensorium as described by me in the present work, and in 



Proc'. Boston BOO. N. History, 1869. The teeth are very large, with marked cutting edges and facets. Vertebra- not 



observed. 



Prof. Marsh informs me thai, the most anterior caudals of M. princeps are sub-pentagonal. 



r 



