CLASSIFICATIONS OF THE AMPHIBIA. 271 



animals by the want or number, of feet, when in their per- 

 fect or full-grown state, the annexed classification may be 

 conveniently used. 



Order I. — Apoda. Without feet. 

 Genus. — Ccecilia. 



Order II. — Dipoda. With two feet. 



Genera. — Siren. Parvibranchus. 



Order III. — Tetrapoda. With four feet. 



Genera. — Rana, Ceratophrys. Hyla. Bufo. Rhinella. Otilopha. 

 Dactylethra. Bombinator. Breviceps. Astrodactylus. Salamandra. Sa- 

 lamandrina. Molge. Triton. Menopoma. Amphiuma. Proteus. Me- 

 nobranchus. Siredon. 



Again, if a third person should arrange all the adult Am- 

 phibia according to their external forms, or mere shapes, the 

 genera may be thus placed in four groups, or, as I shall here 

 call them, orders, for the sake of concinnity. 



Order I. — Anguiformia. Snake-like. 

 Genera. — Cacilia. Amphiuma. Siren. Parvibranchus. 



Order II. — Raniformia. Frog-like. 



Genera. — Rana. Ceratophrys. Hyla. Bufo. Rhinella. Otilopha. 

 Dactylethra. Bombinator. Breviceps. Astrodactylus. 



Order III. — Lacertiformia. Lizard-like. 



Genera. — Salamandra. Salamandrina. Molge. Triton. Menopoma. 

 Proteus. Menobranchus. 



Order IV. — Pisciformia. Fish-like. 

 Genus. — Siredon. 



Having before observed that I selected the permanency of 

 the external gills for the character of an Order, in which to 

 place the Proteus ; I will now subjoin an arrangement, in- 

 cluding both that order, which corresponds with the second 

 order previously instituted by Latreille, l and also his first 

 order. To these I have added two more orders; one, Abran- 



1 But it is interesting to learn from Prof. Owen's paper mentioned above, 

 that the eminent John Hunter first suggested the idea of partly character- 

 ising these animals by their branchiae or gills. Mr. Owen says (p. 214),—. 

 " the Siren, the Amphiuma, the Kaltewagoe or Menopoma of Harlan, in 

 short, all the " reptiles douteux " of Cuvier that Mr. Hunter was acquaint- 

 ed with, he considered as a distinct Class, which he denominates u Pneumo- 

 branchia," in the manuscript which is quoted by Rusconi, in the work 

 entitled 'Amours des Salamandres Aquatiques,' (p. 12, 1821), and which is 

 ^iow published in the ' Physiol. Cat. of the Hunterian Collection,' vol. ii. p. 

 145, 1834. 



