HI-: /'TILES. 



411 



desire to go to the surface to breathe. Their lungs are not large, and so it 

 would seem that they must have the power to extract oxygen from the 

 water, for the supply that they carry down with them could hardly last 

 that length of time. Such is really the case ; and Professor Gage has ascer- 

 tained that in the throat are gills, and he has proved that by means 

 of these gills they actually breathe. 



It is a curious feature often noted, that the same discovery is frequently 

 made by different observers, entirely independent of each other, at about 



^^Is 



< &&/^ 6 " 



Fig. 355. — Hawk's-bill turtle, or caret (Eretmochelys imbricata). 



the same time. In every book it is stated that the turtles breathe only by 

 lungs, but here is one which has gills in addition ; and as soon as Professor 

 Gage had made his announcement in this country, a naturalist in Aus- 

 tralia made the same discovery concerning a turtle in that far-off land. 



Rivalling, or even excelling, the green turtle, comes the terrapin of the 

 southern states. Several species figure under this name, and unless the 

 purchaser know what he is after, he is apt to have some other species put 

 upon him instead of the true salt-water species which he desires. It 

 varies considerably in its appearance ; above, it may be a greenish gray. 



