MORPHOLOGY OP VENOMOUS SNAKES 43 



II. A Row of Rounded, Dark-Bordered Blotches, Well 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 stales 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. 



(&) 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 nsr 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 dwissus 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 19,0. 



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

 familiar 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. 



