216 



lUTLLE'lIN 34, IJNITKD STATES iN'ATli).\AL MUSEUM. 



AMPHIUMA MEANS Gardeu. 



(Plates 9, fig. 7; 10; 11, figs. 1-it; 12; 13, fig. 5.) 



Holb., N. A. Herp., V, p. 89, PI., 30 ; Dnm. &. Bibr., p. 203; Gray, Cat. Batr. 

 Grad. Brit. Miis,, cd. i, p. Sf) ; Bonlenger, Cat. Batr. Grad. Brit. Mus., 

 ed.ii, 1882, p. 83; Cope, Check List Batr. Kept. N. Am., 187.5, p. 25; 

 Proceeds. Amer. Pliilos. Soc, 1886, p. 526. 



Chrysodonia lari'w/ormis Mitch., I. c. 



Amphinina means s. didacti/la Cnv., M^in. Mns. , xiv, p. 4, PI. 1, fig. 1-3. 



Jm2)hiuma didactyla Wagl., S^'st. Ainph., p. 209. 



Sirenoides dida^tyhim Fitz., I. c. 



AmpUuma tridaclyla Cnv.,M^m. Mus., xiv, p. 7, PI. 1, fig. 4-6; Holbr.,N. A. Herp., V, p. 

 9.3, Pi. 31; Tschudi,Batr.,p.97; Diini. & Bibr., p. 203; Eyder Proc. Ac. Phila., 

 1879, p. 14; Bonleiiger, Cat. Batr. Grad. Brit. Mus., ed. ii, 1882, p. 82. 



Mnranopsis tridactyla Fitz., Syst. Reptil. p. 34; Gray, Cat. Bat. Grad. Brit. Mus., ed. 

 I, p. 55 ; Cope, Check-List Batr. Reptil. Nearctic Realm, 1875, p. 25, 



Fig. 55. Atnphiuma means. No. 10865. Columbus, Miss ; -J. 



lu this species tlie general form is elongate, and much like that of 

 an eel. Of this length the tail occupies a proportion which varies from 

 a little less than one-fourth to a little less than one-fifth. This propor- 

 tion (le])en(ls on age, the large adults having shorter tails than the 

 small and young ones. The body is depressed cylindric in form. The 

 form of the tail differs in different individuals from a vertical oval in 

 section, to a triangle in section, with the angle upwards. Its extremit3'' 

 is always strongly compressed, and is slender, and the superior surface 

 may be rounded or angulate. There is no distinct contraction rei^re- 

 senting a neck. The head is an oval, and is narrowed very grad- 



