108 G. R. Wielaiid — On Mar irie Turtles. 



2. ToxocLelydiBge. — No free nasals ; palatine foramen, 

 pterygoids, and lower jaw distinctly Clielydra-like ; two strong 

 claws. 



Genera : Toxochelys^ Poi'thoclielys^ Cynocerciis (f ), all of 

 the Niobrara Cretaceous of Kansas, also NejptunocJielys from 

 the Cretaceous of Mississippi. 



3. Desmatocheljdinse. — Free nasals ; distinct palatine fora- 

 mina (except Rhinochelysl). 



Genera: Desmatochelys, Bhinochelys, Atlaiitochelys. 



4. Chelonin^e. — No free nasals ; no palatine foramina ; 

 vomero7premaxillar union often, but not constantly present ; 

 obturator foramen presumably not enclosed as in Archelon in 

 any member of the group ; claws, one or two. 



Genera : Osteoi^ygis^ Allopleuron^ Lytolovia, Argillochelys, 

 Eretmochelys^ Chelone^ Coljpoclielys^ Thalassochelys. 



•«• -Jf 4f -H- « ^ 



Besume. — In the foregoing notes the following additions to 

 the osteolog}" of the marine Testudinates haye been made : — 



1. The elements and organization of the front flipper of Toxo- 

 chelys. 



2. The main elements of the wrist region of the front flipper 

 of Archelon ischyros. (These are described from the type of 

 the genus and species. The writer, in his first announcement of 

 the discovery of this gigantic turtle, figured and described the 

 accompanying humerus, with the radius and ulna, as well as the 

 femur, tibia, and fibula, — this being the first instance in which 

 all these limb bones were made known in the case of any extinct 

 marine Testudinate.) 



3. Important measurements for the coordination of various 

 skeletal elements of Toxochelys and Archelon. 



4. The deduction (with the exception of the secondary rear- 

 rangements of the carpals) of the principal lines of change in 

 the evolution of the fore flipper from the foot of some primitive 

 swamp, or littoral, C/ielydra-Vike turtle. 



5. The cervical organization of Toxochelys and Archelon, 

 which is compared with that of living turtles. 



6. A classification of the marine turtles. — This has chiefly been 

 made possible by the description during the last few years of 

 large portions of the skeleton of JProtostega and of Toxochelys, 

 and especially by the discovery of Desmatochelys, Archelon, and 

 Porthochelys. 



Yale Museum, New Haven, Conn. 

 April, 1902. 



