22 



Family Dermochelydidse. Leathek Turtles. 



The only family of turtles in which vertebrae and ribs 

 are free and not connected with the carapace proper, which 

 in this case consists of a leathery integument overlying 

 many small suturally united plates. Seven longitudinal 

 rows of these are large and ridge-like ; the intermediary 

 rows are composed of much smaller bones. The plastron 

 is made up of a large, thin median plate, adjoining which 

 there are a few smaller ones. The body is highest in front. 

 The limbs are paddle-like, the anterior pair much the 

 longer. There are no nails on the toes. 



Dermochelys coriacea ( Vandelli). 



Trunkback. Leather Turtle. 



The only species of the family is a large, heavy animal, 

 growing to a length of six to eight feet. The general color 

 is dark brown. It is entirely pelagic in habits and lives in 

 the Atlantic Ocean, northwards as far as Massachusetts 

 and Great Britain. Occasionally met with on our coast. 

 It likewise occurs in the warmer parts of the other oceans. 



Family Oheloniidae. Loggerheads. 



Here the heart-shaped carapace is broad and flat, covered 

 with bony plates. It is highest in front. The plastron 

 consists of nine bones. The limbs are paddle-like, the feet 

 scaleless, the toes bound together by the integument. The 

 head is large, the jaws without tooth-like projections along 

 the edge. This also is a pelagic family and comes shorev/ard 

 only to deposit its eggs. As a whole the Loggerheads 

 include the most valuable of the turtles for economic pur- 

 poses. Tortoise shell comes from a species of this family. 



Thalassochelys caret ta (L.). 



Loggerhead. 



This large species has the plates of the carapace not im- 

 bricated ; there are two nails on each foot ; the cutting 



