76 KEPTJLl.S. 



The former (those in which no branclii;£ are visible) constitute two 

 genera. 



Menopoma, Harlan*. 



Form of a Salamander; eyes apparent, the feet well developed, and an 

 orifice on each side of the neck. Besides the range of small maxillary 

 teeth, there is a parallel row of them on the front of the palate. Such is 

 the reptile termed 



Sal. gigantea, Barton; Great Salamander of North America; 

 Ann. of the New York Lye. I, pi. 17. (The Hellbender of the 

 United States). From fifteen to eighteen inches long; a blackish 

 blue ; inhabits the great lakes and the rivers of the interior. 



AiMPUiuMA, Garden. 



Have an orifice on each side of the neck, but their body excessively 

 elongated ; the legs and feet, on the contrary, but very slightly developed ; 

 the palatine teeth form two longitudinal ranges. 



In one species there are but three toes to each foot; Amph. tri- 

 dactylum, Cuv. ; and in another, Amph. means, Gard. and Harl. but 

 two — Mem. du Mus. XI Y, pi. If. 



Among those which always retain their branchite, the 



AXOLOTUS. 



The Axolots in every respect are similar to the larv^ of an aquatic Sa- 

 lamander, having four toes before, five behind, three long tufted bran- 

 chiae, &c. The maxillary teeth are like velvet, and those on the vo- 

 mer in two bands. Such is the 



Siren pisciformis, Shaw; the Axolotl of the Mexicans; Gen. 

 Zool. vol. III., part ii. pi. 140; Humb. Zool. Obs. I, pi. 12. 

 From eight to ten inches long; grey, spotted with black. It inha- 

 bits the lake that surrounds Mexico^. 



JMenobkanchus, //rtr/r/w.— Nectukus, Raffin. 



Have but four toes to all the feet ; a range of teeth in the intermaxillaries, 

 and another, parallel, but more extended, in the maxillaries. 



* Dr. Harlan fiist called them Abranchus; Leukard and Fitzinger called them 

 Ckyptobkanchus, and others Protonopsis. 



f The yhnphiuma was known to Linnaeus, but at too late a period to allow him to 

 insert it in any of the editiv,,.js of his system which appeared during his life. It has 

 been described since by Dr. Mitcliell, under the name of Chrijsodonta larvrrformis, and 

 by Dr. Harlan under that of Amphiuma. I have described tlie Amph. tridacti/litm of 

 Louisiana, which attains the length of three feet. See Mem. du Mus. tome XIV, 1. 

 I suspect this is the species spoken of by Barton in his letter upon the Siren, as a 

 Siren with four feet. 



:|: It is -sv-ith some hesitation that I place the Axolotl among the genera with per- 

 manent branchiae, but so many witnesses assure us that it does not lose them that I 

 am compelled to do so. 



