iiawk's-bill turtle. 



The structure of the whole family is admirably adapted 

 to their marine habits. The body is flattened so as greatly 

 to facilitate their progress through the water ; the feet are 

 formed into the most perfect oars, by means of which they 

 are propelled with considerable force and velocity ; " the 

 Green and Hawk-billed in particular," says Audubon, " re- 

 mind you, by their celerity, and the ease of their motions, 

 of the progress of a bird in the air." The head is so placed 

 upon the neck as to allow of the nostrils being readily 

 raised above the surface for the purpose of occasional 

 respiration. The nostrils, also, are furnished with a fleshy 

 valve, which is closed when the animal is submerged, but 

 opens when required for respiration. 



The food of the Green Turtle consists of marine plants, 

 especially the sea-wrack, Zostera marina ; and they graze 

 at the bottom of the water, coming at intervals to the 

 surface to breathe. As this mode of taking their food 

 renders them very liable to swallow, with their aliment, 

 a considerable quantity of sea-water, there is a beauti- 

 ful structure lining the interior of the oesophagus, by 

 which this circumstance is effectually obviated. This 

 consists of a great number of horny pyramidal bodies, 

 with which the whole interior of the oesophagus is fur- 

 nished, all of them directed backwards towards the sto- 

 mach ; by which means, although the food and the water 

 together can be readily swallowed, yet, when the stomach 

 is contracted for the purpose of regurgitating the water, 

 the food itself is retained. " The Hawk-billed species 

 feeds on sea-weeds, crabs, various kinds of shell-fish, and 

 fishes ; the Loggerhead mostly on the fish of conch shells 

 of large size, which they are enabled, by means of their 

 powerful beak, to crush to pieces with apparently as much 

 ease as a man cracks a walnut. The Trunk Turtle feeds 



B 2 



