MORPHOLOGY OF VENOMOUS SNAKES 41 



Lachesis sumatranus. 



Color bright green with or without black crossbands; yellowish band on each 

 side; belly yellow or green with or without black speckles; end of tail red. 

 Length about 3.5 feet. Singapore, Sumatra, Borneo, Palawan. 



Lachesis anamallensis. (Plate 17, D.) 



Color green, olive, yellow or reddish-brown; black temporal band; belly pale 

 green; tail usually black or yellow. Length 2.5 feet. Anamallay and Nilgherries, 

 southern India. 



Lachesis trigonocephalus. 



Coloration similar to preceding. Length about 2.5 feet. Ceylon. 

 Lachesis macrolepis. 



Color bright green or olive. Belly pale green. Length about 2 feet. Southern 

 parts of India. 



B. First infralabial plate is divided; the separated portion forms a 

 pair of small supplementary dental plates; 144 to 176 ventrals; 

 38 to 57 subcaudals; tail prehensile. 

 Lachesis puniceus. 



Scales in 21 to 23 rows. General coloration gray, brown, or red; belly spotted 

 brownish; end of tail red. Length 2 feet. Java, Borneo. 



Lachesis borneensis. 



Length about 2.2 feet. Borneo, Sumatra. 



C. Scales in 19 to 27 rows; ventrals 127 to 156, subcaudals 



45 to 55. Tail prehensile. 

 Lachesis wagleri. 



Color green with lighter or deeper black and yellow speckles. Length about 

 3 feet. Malay Archipelago and Peninsula. 



Genus SISTRURUS Garman. 



Head very distinct from neck, covered with 9 large symmetric plates. 1 Eyes rather 

 small, with vertical pupils. Body cylindrical; scales carinated, apical fossa. Tail 

 short, terminated by a horny appendix which produces a peculiar sound (the 

 rattle); subcaudals for the most part in one row. 



Sistrurus miliarius. " Southern Pigmy Rattlesnake." 



A very small species with stout body and distinct, flattened head. Tail thin, 

 minute rattle. Dark ashy gray, with a series of large, black blotches on the back, 

 these irregularly rounded and separated by reddish spaces; on the sides are several 

 series of black spots, smaller and less distinct than those on the back; tail un- 

 usually reddish ; belly white, thickly marbled with black spots or blotches. Length 

 about 1.8 feet. Florida, central North Carolina, coastal region along the Gulf of 

 Mexico to Texas. Along the Mississippi valley'to Arkansas and central Oklahoma. 



Sistrurus catenates. " Massasauga." (Plate 19, A.) 



Large and comparatively stouter snake than S. miliarius. Tail shorter, rattle 

 better developed. Ground-color grayish-brown, with a series of large, rich-brown 

 blotches on the back, these faintly bordered with white; tail ringed with dark 

 brown; belly dull gray marbled with black or entirely black; throat paler. The 

 maximum number of joints of the rattles examined by Ditmars was eight. Length 

 about 2.5 feet, but reaches 3.5 feet. 



1 Crotaltts is covered with granular scales. 



