338 G. R. Wietand—On Marine Turtles. 



on such meager skeletal parts accumulate in the course of 

 time ; but surely we are permitted little diffidence in applying 

 the laws of priority and nomenclature now in vogue to a hand- 

 some and reasonably complete fossil like that discussed in the 

 present paper. Perhaps the day is not distant when fragments 

 will be merely noted within generic limits, and then numbered 

 and laid aside for a certain number of years before being 

 arbitrarily dignified as the types of new forms. Assuredly 

 such a method would simplify the study of extinct faunae. 

 The extreme difficulty of reaching accurate specific identifica- 

 tions after most painstaking comparisons and study of descrip- 

 tions primarily based on fragmentary material, has been espe- 

 cially brought home to the writer in his consideration of the 

 Upper Cretaceous Turtles of JNew Jersey, and he has great 

 sympathy with Professor Marsh's oft repeated contention that 

 the types of extinct vertebrates ought to be mainly founded 

 on fairly complete forms. 



With the isolated and imperfect skull of rather large and 

 robust form named T. procax by Hay, as with that of T. 

 orachyrhinus, no comparisons are afforded by the material 

 thus far obtained. 



From T. (serrifer) stenoporus, finally, T. Bauri differs 

 distinctly, as shown by comparison with' the posterior half 

 of the carapace figured by Case.* From that and other 

 specimens of T. (serrifer) stenoporus the present fossil differs 

 in being of a larger type with relatively heavier marginals 

 and larger pleural plates ; also in the much more pronounced 

 sutural union of the postero- and margin alo-pygal, which is 

 reduced to peg-like junction in T. {serrifer) stenoporus. 



Systematic Position of the Genus Toxochelys. 



Because of the carapacial organization with much reduced 

 pleurals and marginals, as well as certain plastral characters, 

 all suggesting primitive relationships to the Cheloniidse, it 

 was first suggested by the writer on his discovery of the 

 organization of the front leg of Toxochelys latiremis, that the 

 Toxochelyds do not justly constitute a separate family of tur- 

 tles, as proposed by Cope and held by Hay, but are better 

 classified as a sub-family of the Cheloniidge, the Toxochely- 

 dinse. Recently Hay, while accepting the principle that the 

 limbs do furnish "a test of the correctness of this disposition 

 of the genus," interprets the evidence differently (7). He now 

 reaches the conclusion that Wieland misinterpreted the limbs 

 of T. latiremus (10), and that these, as in the Trionychid 

 Amy da spinifera, were merely long fingered and webbed, 

 * Kansas Univ. Gfeol. Sur., vol. iv, plate lxxxiii. 



