36 CHELYDRA. 



(i. glutinala. Sterni lobis immobilibus (v. t. Mus. Brit.) 

 Hab, in America Boreali. 



Gen. 4. CHELYDRA, Schw. 



Sternum angustissimum cruciforme centro coriaceo, scu- 

 tella membranacea, symphysis gracilis elongata scutello pro- 

 prio tecta. 



The head large and beak horny, like the other Terrapins, 

 but the sternum is very narrow and cross-shaped. All the 

 bones of which it is formed resemble those of the genus 

 Trionyx and Chelonia ; they are only covered with five pairs 

 of very thin skin-like sternal plates. The symphysis between 

 the sternum and the back shell is very long and narrow, and 

 covered with a peculiar plate which may represent the pair 

 that are deficient in the centre of the sternum. The axillary 

 and inguinal plates are distinct and equally thin. The limbs 

 are large and strong, and the tail is long and longitudinally 

 crested on the upper surface. 



This genus consists of only a single species, which, from its 

 resemblance to the Alligator, has been called the Alligator 

 Tortoise. It is Emj/s, section B. of Oppel, and it has been 

 called Chelonura. by Fleming, Saurochelys, by Latreille, and 

 Rapara, by myself ; but I have adopted here the oldest name, 

 published in a paper which I could not find when T first 

 wrote of these animals. 



Chelydra serpentina, {Alligator Terrapin.) Testd oblonga, 

 medio depressa bicarinata, postice obtuse dentata. 



Test, serrata. Penn. Arct. ZooL not Shaw. Chelydra 

 lacertina, Schw. (v. Mus. Brit.) Howit Liverpool Mus. t. 



Junior. Testa tricarinata postice acute dentata. Test, 

 serpentina, Lin. Schoepf, t. 6, cop. t. Daud. t. 60, f. 2, and 

 Shaw, Zool. t. 29. Chelydra serpentina, Schw. Chelonura 

 serpentina, Say. Test, longicauda, Shaw, Mss. Mus. Col. 

 Surg. (Pullus.) 



Hab. in America Boreali, (v. v. Exeter Change, v. t. Mus. 

 Brit. Par. ct D. Bell), called coulta by the slaves. 



