16 TRIONYX FEROX. 



Chelys matamata (fimbriata). This can hardly be, for though the Chelys mata- 

 mata is mentioned in Barrere's Natural History of Guiana, at that time called 

 "La France Equinoxiale," yet the first figure given of it was by Bruguiere in 

 "Le Journal d'Histoire Naturelle de Paris," for 1792, which is so good a one 

 that it has been repeatedly copied by other naturalists, as Schoepff, &c. Now 

 Bartram's work was published in Philadelphia in 1791, consequently he cannot 

 be accused of this deception. Bartram was an upright though somewhat over 

 credulous naturalist. 



I can adopt neither the generic name Aspedonectes of Wiigler, nor that of 

 Gymnopus of Dumeril; for though it might be necessary to subdivide the genus 

 Trionyx to accommodate all the species with soft shells and three nails, yet in 

 that case I would follow the example of Gray and Bell and retain the name 

 Trionyx for the typical form, as it has been consecrated by time, and apply the 

 new epithet of Amyda, or Aspedonectes, to those that vary from it in proportion 

 of parts, &c., as these must be considered as abnormal forms. 



