TRIMERESURUS GRAMINEUS. 385 



When roused these snakes are extremely fierce, striking at everything within their reach, 

 and Cantor says that in the extreme of fury they will fix the fangs in their own bodies. 

 Frogs, mammals, and birds form their food, and I have never found a lizard or snake in 

 their stomach. 



The Trimeresures occur only in the East Indies, and belong to a tribe of snakes which is 

 provided with a singular pit in the loreal region, and found in the New and Old World. We 

 are not at present acquainted with the use of this organ. The following species are known : — 



* The second upper labial shield forms the front part of the facial pit ; the last ventral shields entire ; 



ventral shields less than 200. 

 Grass-green. Scales in nineteen or twenty-one rows ; one or two small 



shields between the supranasals T. gramineus, p. 385. 



Grass-green. Scales in twenty-one rows; supranasals in immediate 



contact with each other T. erythrurus, p. 386. 



Grass-green. Scales in twenty-three or twenty-five rows T. carinatus, p. 386. 



Upper parts dull reddish brown. Scales in twenty-five or twenty-seven 



rows T. purpureus, p. 387. 



A black or brown temporal band. Scales in tn'enty-one series . . . T. anamallensis, p. 387. 

 Ground-colour brown or black; a yellow temporal band. Scales in 



twenty-three series T. monticola, p. 388. 



** The shield forming the front part of the facial pit is separate from the second upper labial ; ventral 

 shields less than 200. 



Scales in twenty-three or twenty-five rows T. wagleri,^. ^S^. 



Ground-colour brown. Scales in twenty-one rows T. strigatus, p. 389. 



*** The ventral shield before the anal is deeply notched or divided into two; ventral shields less 

 than 200. 

 Scales in seventeen or nineteen rows T. trigonocephalus, p. 390. 



**** Ventral shields more than 200. 



Brownish grey above with black rings T. mucrosquamatus , p. 390. 



Trimeeesurus gramineus. 



Russell, Ind. Serp. i. pi. 9. 



Coluber gramineus, Shaw, Zool. iii. p. 420. 



Vipera viiidis, Baud. Rept. vi. p. 112. 



gramineus, Cantor, Mai. Rept. p. 119. 



Trimesurus viridis. Gray, Ann. ^ Mag. Nat. Hist. 1842, xii. p. 391. 

 elegans. Gray, Ann. §• Mag. Nat. Hist. 1853, xii. p. 391 (young). 



The second upper labial shield forms the front part of the facial pit. The supranasal is 

 separated from its fellow by an azygos shield or by a pair of very small shields, situated 

 behind the rostral. Scales in from nineteen to twenty-one rows; 

 those on the crown of the head smooth or very indistinctly keeled. 

 Ventrals 158-170 ; subcaudals 58-71. Grass-green above, lighter 

 on the sides ; tail sometimes cinnamon-red ; a yellow or brick-red 

 line runs from behind the eye along the outer series of scales. 

 Lower parts pale greenish. 



3d 



