MORPHOLOGY OF VENOMOUS SNAKES 43 
II. A Row or ROUNDED, DARK-BORDERED BLOTCHES, WELL SEPARATED. 
(2) No horn over the eye: 
A pale band, one scale wide, in front of eye. (Central United States, Canada 
LONE CEICO) ete a ter itnthe ots eietelaraie al sl> oloiis akei eve) sel sie /elelarsietolelel s\el= ..- Crotalus confluentus. 
A pale band, two scales wide, in front of eye. (Extreme western United 
SCALES) Meee rey sree: ora stabs) wacactelt elo hat hel otarnlshetadatetoreloiegetal ole) chet ei sete (or siei(el=.0) sie! Crotalus oregonus. 
Two rows of blotches on anterior part, fusing into a single row in rear of body. 
(Arizonavamd IWlexico) iets ce cre soreiete clots ehevetareleale cine lofe e elerel« cleleloe- ete Crotalus pricet. 
(6) A horn over each eye: 
Yellowish; square, dull blotches on back and black spots on sides. (Deserts 
Ob Arizona NE VAG Asta Calif OxMId) ey merieloe ste eres clolele eo ole eletal ats lavas 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 
POLIS) Ree efarmeree eccrine cues eace ei sintcray ote ce Grctatchahanere oro) stsyetere) cleaners Crotalus horridus . 
(6) 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 Galitonias ArizomasINEVAGd) i: ae acces cies cvs volo a sis Stee aioe Crotalus tigris. 
Greenish; narrow and regular black bands at a considerable distance apart. 
(Region of the Mexican boundary, from western Texas to western 
PATIO) cere Nate, isae Poca ce erale STOTT aR IS ca cesT over vs wiles kone sie erro the Crotalus lepidus. 
Crotalus adamanteus Beauvois. ‘‘ Diamond-back Rattlesnake.’’ (Plate 10, B.) 
Crotalus durissus Linneus. 
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 18r 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 Linneus. “ Banded Rattlesnake” or ‘‘ Timber Rattlesnake.” (Plate 13,F; plate 19, C. 
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. 
