264 Louis Dollo—On the Humerus of Euclastes. 
B. If their size corresponded equally with that both of Trionya 
and of Huclastes, which is not the case; 
C. If the fossilization, and especially the colour, had been the 
same, which they are not; 
they ought still, according to the law of probability, to be referred 
to Huclastes ; 
6. Lastly, on the other side of the Atlantic, Mr. KE. D. Cope has 
made known, a long time ago,! that the Cretaceous Proplewride had 
a more chelydroid than chelonoid humerus, and he was so much 
impressed by this structure, amongst others, that he began by 
placing with the Chelydride the genera which have since composed 
his Propleuride. 
After what has been said above, it seems to me beyond doubt that 
the humeri described as belonging to Euclastes really appertain to 
that genus. 
However, a further verification, which I am going to mention, 
appears to me possible. The Erquelinnes Chelonians are imbedded 
in sand, consequently in a matrix devoid of cohesion; on the con- 
trary, the London Clay Chelonians, several of which ought certainly 
to be classed among the Propleurid@,? are found not only in clay, 
a more coherent substance, but each of them is said to be included 
in a “nodule of petrified clay.” ? Under these conditions, the latter 
show with more certitude the bones which come from the same 
individual. Now, Chelone longiceps,t Owen, is one of the types 
belonging to the Propleuride, as I understand them, and the skull, 
the carapace, as also the humerus, are still adhering together.’ If, 
then, the humerus is of the shape of our Fig. 2 (Huclastes Gosselett, 
Dollo), the above-mentioned verification will be made. Therefore, 
it is to be wished that an English naturalist should consent to 
examine this point; and it is precisely to make known this desidera- 
tum that I have chosen the pages of the GrotogicaL MaGazine to 
publish the present paper. I am aware that Sir R. Owen says, 
speaking of the humerus in question: “The humerus presents the 
usual characters of that of the Chelones.”® But the celebrated 
naturalist may not have had his attention especially drawn to this 
bone ; moreover, judging by the figure which he gives of it,’ it 
appears to me somewhat mutilated, as also imperfectly cleared of its 
matrix. I shall add that it is not one specimen only that should be 
studied, but all those coming from the London Clay, which can be 
referred to Propleuride, and in which the humerus is associated, 
beyond a doubt, with other characteristic remains. 
VUI.—It ought to be inferred from the preceding pages that the 
Propieuride were Turtles not so well adapted to an aquatic life as 
1 E. D. Cope, ‘‘ Synopsis,” ete., pp. 180 et 235. 
2 L. Dollo, ‘‘Chéloniens landéniens,’’ etc., p. 137; R. Lydekker and G. A. 
Boulenger, ‘‘ Notes on Chelonia,’’ etc., Grou. Mac. p. 271. 
5 R. Owen and T. Bell, ‘‘ Monograph,” ete., p. 40. 
4 R. Owen and T. Bell, ‘‘Monograph,”’ etc., p. 16. 
> R. Owen and T. Bell, ‘‘ Monograph,” ete., pl. iv. 
6 R. Owen and T. Bell, ‘ Monograph,” etc., p. 17. 
7 R. Owen and T. Bell, ‘‘ Monograph,”’ etc., pl. iv. 
