290 CR0C0DIL^).^5. 



1. Alligator mississippiensis. 



Crocodilus mississippiensis, Baud. Itept. ii. p. 412 (IBOlJ). 



lucius, Car. Ann. Mus. x. p. 32 (1807), and O*'*-. Fon". v. 



pt. ii. p. 32, pis. i. .'v: ii. (1824) ; Tiedem., 0pp., ^- Lib. Nat. Amph. 



p. 58, pi. iv (1817) ; Harlan, Med. Zool. Res. ^. 140(183-5). 

 — cuvieri. Leach, Zuol. Misc. ii. p. 117, pi. cii. (ISlo). 



AUi-^ator lucius, Bon/ dc St. Vine. Diet. Class. iVIl. N. v. p. 100 



(1824) ; Dum. S,- liibr. iii. p. 7'), pis. xxv. & xxvi. (183G). 



cuvieri, Bori/ de St. Vine. I. c. p. 104. 



mississippiensis, Grat/, Syn. Rept. p. 02 (1831) ; Holhr. N. Am. 



Ilerp. ii. p. -5.3, pi. vi. (1842); Graii, Cat. Tort. ^'t. p. 00 (1844); 



Strauch, Si/n. Crocod. pp. 15 & GO (1800) : Grai/, Trans. Zool. Sue. 



vi. p. 108 (1809), and Cat. S/t. Rept. ii. p.' 29 (1872); Chajfanjon, 



Ann. Soc. Linn. Lyon, xxviii. p. 63 (1882). 



10 or 20 upper and as many lower teeth on eacli side. Head 

 nearly twice as long as broad; snout much depressed, broadly 

 rounded at the end, with the lateral outline nearly straight ; a very 

 short ridge in front of the orbit ; upper eyelid bony anteriorly. 

 Two pairs of large uuchal scutes, forming a square, separated on the 

 median line, with a pair of small ones in front and another pair 

 behind. 17 or 18 transverse series of dorsal scutes, the broadest 

 composed of 8 scutes. Fingers hardly half-webbed, outer toes about 

 two-thirds webbed. Tail strongly compressed and crested poste- 

 riorly. Dark green or blackish above, young with yellowish cross- 

 bands ; lower parts yellowish. 



Total length 2 metres 20 centim.; reaches a length of 4|| metres. 



South-eastern L^nited States, from the mouth of the liio Grande 

 to North Carolina. 



a. Hgr., stffd. Daupliin Island, Major De Bathe [P.]. 



Mobile Bay. (Type of C. cuvieri). 



b. Yg., spir. New Orleans. 



c-d. Yg., spir. N. America. Lord AmptliiU [P.]. 



e. Yg., stffd. N. America. E. Boubleday, Esq. [P.]. 



/, (J, h, i, k. Ad., N. America. 



ligr., & yg., stffd. 



I, m, n, 0. Hgr. & N. America. 



yg., skels. 



2). Ad., skull. N. America. 



q. Ad., skull. N. America. Dr. Falconer [P.]. 



2. Alligator helois. 



Alligator helois, Cope, Proe. Ac. Philad. 1805, p. 185. 



Two keels behind and between the eyes, diverging posteriorly ; a 

 short and nearly transverse keel in frontof the eyes. Two oblique rows 

 of elevated horn-like scutes on each side of the neck, of rather small 

 size, four in the inner, three in the outer row, the third of the inner 

 and tlie second of the outer forming, with two large elevated median 

 scutes, a transverse row. Eight longitudinal rows of dorsal scutes 



