CROCODILIANS. LIZARDS, AND SNAKES. 761 



hiive no representatives in ecjuatorial America or the West Indies. A 

 genus Lystrophu Cope', is found in subtropical and temperate South 

 America, which resembles HeUrodon superficially, but belongs to the 

 Xenodontida'. A genus occurs in Madagascar [Anomalodon Jan) 

 which agrees su])erflcially with Lystrophi.s^ but dififers in having an 

 entire anal shield, but belongs by the penial characters to the Lyco- 

 dontinae. 



The species of Heierodon have some peculiar habits which indicate 

 greater intelligence than most other snakes possess. They throw 

 themselves into remarkable contortions when alarmed, and expand 

 their anterior ribs, inflate their lung, and open the mouth widely. 

 They do not attempt to bite from the ground, but the long posterior 

 maxillary tooth may be used with considerable effect if the snake is 

 carelessly handled. The trowel-shaped rostral plate enables them to 

 excavate sand with ease, and in such soil they are usually most 

 abundant. 



Three species of this genus may be distinguished as follows : 



I, No accessory scales about the azygous plate. 



Scales in 25 rows ; rostral plate less developed ; larger H. platyrMnus. 



II. Accessory scales about the azygous scuta. 



Scales in 25 rows; stouter, smaller; an inferior nasal plate; one row of lateral 

 spots; belly white in adults H. sivius. 



Scales in 23 rows; smaller, more slender; no inferior nasal scuta; two rows of 

 lateral spots; belly more or less black H. nasicus. 



The H. platyrhinus ranges throughout the Eastern and Austroripa- 

 rian regions, and the H. simus inhabits the Austroriparian only. The 

 H. nasicus is divided into two subspecies, one of which extends over 

 the Central and the other over the Sonorau regions. 



HETERODON PLATYRHINUS Latreille. 



Heierodon lylatyrhinus Latreille, Hist. Nat. des Eeptiles, 1\ , 1800, p. 32, figs. 



1-3.— HoLimoOK, N. Anier. Herp., II, 1828, p. 97, pi. xxi; 2d ed., IV, 1842, 



p. 67, pi. xvn.— Dumi;;ril aud Bibrox, Erp. G6n., VIII, 1854, p. 765.— Baird 



and GiRAHD, Cat. N. Amer. Kept., 18-53, p. 51.— Cope, Check-list N. Amcr. 



Batr. Rept., 1875, p. 43.— Boulengeh, Cat. Snakes Brit. Mus., II, 1894, p. 154. 

 Coluber heierodon Daudin, Hist. Nat. Repfc., VII, 1799, p. 153, pi. 60, fig. 28.— 



Say, Amer. .Journ. Sci. Arts., I, 1818, p. 261. — Harlan, .Journ. Acad. Nat. Sci. 



Phila., 1827, p. 357. 

 Coluber cacodwmon Shaw, Gen. Zool., Ill, 1802, p. 377, pi. 102. 

 Scytale niger Daudin, Hist. Nat. Rept., V, 180.3, p. 342.— Harlan, .Toiini. Acad. 



Nat. Sci. Phila., 1827, V, p. 367. 

 Pelias niger Merrem, Tentiiraen, 1820, ]>. 149. 

 Heierodon niger Troost, Ann. Lye. Nat. Hist., New York, III, 1836, p. 186. — HoL- 



BROOK, N. Amer. Herp., IV, 1842, p. 63, j)]. xvi.— Bairo and Gihard, Cat. 



N. Amer. Rept., 1853, p. 55.— Dum^ril and Bibrox, Krp.'Gf^u., VII, p. 769. 

 Heierodon cognaiua Baird and Giraro, Cat. N. Amer. Rept., 1853, p. 54. 

 Heierodon atmodes Baird and Girard, Cat. N. Amer. Rept., 1853, p. 57. 

 Parietals and frontal longer than broad, about eciual in length. 

 Center of eye anterior. Dorsal rows twenty-five, all cariuated, the 



' Bull. U. S. Nat. Mu8., No. 32, 1887, p. 54. 



