126 G. B. Wieland—On Marine Turtles. 



is largest, not smallest as in Protostega gigas. In closing this 

 brief description of the flippers of A. ischyros, type, it should 

 be emphasized that while there is marked resemblance to 

 Protostega, it is only the resemblance of members of the same 

 family, and that the chief variation is in the humerus and the 

 pes. [The other region of marked variation is on the neural 

 line ; the crania do not differ greatly.] 



The more important measurements of Archelon ischyros, 

 type, are as follows : — 



[Weight of humerus, exactly 75 pounds = 34 kilograms.] 

 Length of cranium from beak to occipital condyle 'd0 ,cm 



" four distal oervicals (estimated).. 35- 



" four proximal cervicals (present) 33' 



" ten dorsal centra measured on the ven- 

 tral face 125* 



" two sacral vertebrae 9*5 



" eighteen caudal centra (estimated ; only 

 a lew of the more distal members are 

 absent) _ 67* ± 



Total absolute length from beak to tip of tail, 

 from measurements on ventral face of centra 329*5 



(The corresponding total exterior measurement is not so 

 accurately obtained, being slightly affected by pressure, but 

 must have been 3*4 m = 11 feet.) 



Length of first dorsal centrum _•_ 8* cra 



" second " " 15 



" third " " . 16-5 



" fourth " " 16-5 



" fifth " " ., ]65 



" sixth " " 14*5 



" seventh" " 14' 



" eighth " ■" 10* 



" ninth " " 7* 



" tenth " " 6- 



Total length of ten dorsal centra 124*0 



Length of first sacral centrum 5 • 



" second " " 4'5 



" first caudal " 4*5 



" second " " ._ ._ 4*5 



" third " " 4-5 



fourth " " 4-0 



fifth " " 4-0 



sixth " " .. 3-0 



