636 REPTILES AND AMPHIBIANS. 
the Snapping Turtle, preys upon frogs, fishes, and young ducks; while 
Trionyx ferox is said to feed upon fish and small aquatic reptiles. 
Serpents vary full as much as turtles in regard to food. For instance 
Thopeltis vernalis, the Green Snake, is insectivorous; Diadophis punctatus 
the Ring-necked Snake, eats worms, insects, and grubs; Storeria dekayt, 
the Little Brown Snake, has been found with the elytra of beetles in its 
stomach; Hutzenia sirtalis feeds upon frogs, toads, and small quadrupeds; 
Abastor erythrogrammus takes rats; Bascanion flagelliforme, the Coach- 
whip Snake, preys upon birds; Boa Constrictors and Pythons swallow their 
species; Ancistrodon contoririx, the Copperhead, eats mice, Ranide, and 
small birds; Pitycphis melanoleucus takes mice, rats, rabbits, and young 
chickens; Ophibolus triangulus uses frogs and toads ; Bascanton constrictor, 
the Blue Racer, consumes frogs, small birds, and other snakes, having been 
observed swallowing a dead Eutznia ; while in the stomach of Tropidonotus 
stpedon, the Water Snake, I have found frogs and small fishes, and in 
Ophibolus getulus, the Chain Snake, the remains of other serpents; Crotalus 
durissus, the Rattlesnake, is said to live upon insects, frogs, lizards, mice, 
moles, young birds, and chickens. Toads are ordinarily believed to be 
eaten by serpents. However, the writer’s experience, having in vain 
endeavored to feed them to Bascanion constrictor and Crotalophorus ter- 
geminus, leads him to believe that toads are rarely preyed upon by snakes, 
but that they are sometimes eaten by Eutexnia sirtalis and Ophibolus 
triangulus is, it appears, beyond question. The former he has himself 
seen in the act of swallowing a Bufo americanus. 
The fangs of the venomous serpents* are firmly soldered to the lower 
side of the maxillary bone, which joins the lachrymal above by a 
ginglymoid articulation. Posteriorly it is in contact with the external 
pterygoid and palate bones. A muscle, the spheno-pterygoid, which has 
no analogue in other animals, extends from the base of the cranium in 
the middle line, backward and outward, to be inserted into the external 
pterygoid, which by contraction it draws forward, pushing the maxillary 
before it and causing the fangs to be erected. At the same time, other 
muscles cause the mouth to be widely opened and the anterior portion 
of the body to be thrown forward, downward, or backward toward the 
object aimed at. If the enemy is missed, the venom may spirt several 
feet, but if struck, another pair of muscles, the external pterygoid, which 
run from the point of articulation of the lower jaw forwards, and are 
spread out as a fascial layer over the gland, and inserted by two slips 
*For a fuller treatise upon Crotalus poisoning, its venom and antidotes, see the ex- 
cellent article by Dr. S. Wier Mitchell, Smithsonian Cont., vol. xii, to which the author 
is largely indebted for facts here given. 
