78 CROTALUSADAMANTEUS. 



the pupil elliptical, vertical and dark; the iris light gray, with a tinge of yellow. 

 The mouth is large, the upper jaw furnished with poisonous fangs, and covered 

 externally with twelve labial plates, all of which are quadrilateral, the largest in 

 front. The neck is remarkably small and contracted; the body elongated, very 

 thick, even to the tail; above it is covered with scales, approaching an hexagonal 

 form, strongly carinated on the mesial line, less so near the abdomen, which is 

 covered with very large plates. The tail is short and thick, with scales and plates 

 below, and sustains a greater or less number of rattles. 



Colour. The head is very dark brown above, with a light coloured line 

 descending from near the snout to the angle of the mouth; above this is a broad 

 black vitta, reaching from the orbit of the eye nearly to the neck; and above this 

 again is a white line of the same extent and direction. The neck and body are 

 a dusky-brown, sometimes tinged with a dusky-green — indeed the whole colour 

 of this animal is singularly dingy — the body is marked with a series of regular 

 rhombs of the darkest-brown, lighter towards the middle; each rhomb is bordered 

 with a margin of dirty-white; these gradually disappear towards the tail, and their 

 place is supplied by dusky bars, which at the end also disappear; the tail is dusky 

 near the rattles. 



Dimensions. Length of head, 2| inches; greatest breadth of head, 2£ inches; 

 circumference of the neck, 4 inches; length of body, GO inches; length of tail, 2£ 

 inches; length of rattles, 3 inches. In the individual here described, there were 

 172 abdominal plates, and 25 plates under the tail. 



Habits. The Crotalus adamanteus chooses damp and shady places, keeping 

 constantly near the water, from which circumstance it is commonly called "the 

 water-rattle," though there is no evidence of their taking to the water in search 

 of prey. 



Geographical Distribution. Its range seems very limited. Hitherto it has 

 never been found north of Carolina, where it is common on the sea board; it 



