MORPHOLOGY OF VENOMOUS SNAKES 43 



II. A Row OF ROUNDED, DARK-BORDERED BLOTCHES, WELI, SEPARATED. 



(a) No horn over the eye : 



A pale band, one scale wide, in front of eye. (Central United States, Canada 



to Mexico) Crotalus confluentus. 



A pale band, two scales wide, in front of eye. (Extreme western United 



States) Crotalus oregonus. 



Two rows of blotches on anterior part, fusing into a single row in rear of body. 



(Arizona and Mexico) Crotalus pricei. 



(b) A horn over each eye : 



Yellowish; square, dull blotches on back and black spots on sides. (Deserts 



of Arizona, Nevada, and California) Crotalus cerastes. 



III. MARKINGS IN THE FORM OF DARK, TRANSVERSE BANDS. 



(a) Bands angular : 



Bands regular in the rear sometimes broken into three blotches the central 

 the largest. (Eastern United States, Vermont to Florida; westward to the 

 plains) Crotalus horridus . 



(b) Bands even : 



Yellowish or gray; three series of blotches on anterior portion of body. On 

 latter two-thirds of body bands closely situated. (Desert mountains of 

 southern California, Arizona, Nevada) Crotalus tigris. 



Greenish; narrow and regular black bands at a considerable distance apart. 

 (Region of the Mexican boundary, from western Texas to western 

 Arizona) Crotalus lepidus. 



Crotalus adamanteus Beauvois. " Diamond-back Rattlesnake." (Plate 19, B.) 

 Crotalus durissus Linnaeus. 



This is the largest species of the whole family and grows over 6 feet and even 

 up to 8 feet in some specimens. Body stout and heavy. Head broad, flat, and dis- 

 tinct from the neck. Scales in 25 to 29 rows, the dorsals highly carinated; 169 

 to 181 ventrals; 24 to 32 subcaudals. The poison fangs are of highest efficiency 

 both in structure and in dimension. Coloration olive or grayish-green, with a 

 chain of large, diamond markings of a darker hue, these with bright yellow borders 

 about the width of a single scale; toward the tail they become obscure and fuse 

 into crossbands; the tail on top is olive, ringed with black; belly dull yellow. 

 Southeastern United States, from North Carolina to Florida and along the mouth 

 of the Mississippi. 



This reptile is said to be very bold and alert. A diamond rattler seldom glides 

 for cover, if disturbed. Pine swamps and hummock lands are its favorite haunts. 

 It is mostly of a nocturnal nature and hunts its prey after twilight. Wild rabbits, 

 rats, birds, and the like constitute its food. It swims well, but seldom climbs trees. 



Crotalus horridus Linnaeus. " Banded Rattlesnake" or " Timber Rattlesnake." (Plate 13, F; plate 19, c. 



The general scutellation is similar to the Crotalus adamanteus. The most 

 familiai: coloration is that of a sulphur-yellow ground-color, with wide, dark-brown 

 or black crossbands, these usually wavy or sharply pointed in the rear; tail black. 

 Another common phase is olive. On the anterior portion of the body are three 

 series of dark blotches, margined with yellow; these fuse into wavy, yellow-edged 

 crossbands on posterior two-thirds of body; belly uniformly yellow or spotted with 

 black on yellow. Length about 3.5 to 4"feet. 



Central Vermont to the northern portion of Florida, thence westward to Iowa, 

 Kansas, Indian Territory, eastern Texas. Abundant in the coastal regions of the 

 Atlantic and the Gulf (variety cane-brake rattlesnake). The mountains of south- 

 ern New York, Massachusetts, and eastern Pennsylvania. 



