2444 



TORTOISES, TURTLES, AND PLESIOSAURS 



LEATHERY TURTLES 

 Family DERMOCHELTID^E 



The remarkable leathery turtle or luth (Dermochelys coriacea), which is the 

 solitary survivor of a series of extinct forms, is one of those animals whose serial 

 position is a matter of dispute among naturalists; some of whom regard it as so 

 different from all other Chelonians, that it ought to represent a suborder by itself, 

 while others believe it to be merely a highly-specialized form allied to the true 

 turtles. From the evidence afforded by extinct species, the latter view, to our 



LEATHERY TURTLE. 

 (One-twentieth natural size.) 



thinking, appears the more likely to be the true one. The essential peculiarity of 

 the leathery turtle is to be found in the nature of its carapace, which is a mosaic- 

 like structure composed of a number of irregular discs of bone closely joined, 

 and entirely free from the backbone and ribs. In certain extinct forms the 

 carapace, on the other hand, is represented merely by a row of marginal bones, 

 from which it is inferred that these reptiles have been derived from true turtles by 



