CROTALUS HORRIDUS. 



and freckles. At the extremity of the tail is situated the rattle, 

 consisting of several hard, dry, bony processes. It consists, 

 in fact, of a number of hollow, hard, dry, and semi-transpar- 

 ent bones, nearly of the same size and figure, resembling in 

 some degree the shape of the human os sacrum, for although 

 only the last or terminal one seems to have a rigid epiphysis 

 joined to it, yet have every one of them the like ; so that the 

 tip of every uppermost bone runs within two of the bones 

 below it ; by which they have not only a movable coherence, 

 but also make a more multiplied sound, each bone hitting 

 against two others at the same time. The rattle is placed 

 with the broad part perpendicular to the body, and not hori- 

 zontal, and the first joint is fastened to the last vertebra of the 

 tail by means of a thick muscle under it, as well as by the 

 membranes which unite it to the skin ; all the remaining 

 bones are so many extraneous bodies, as it were, or perfect- 

 ly unconnected to the tail by any other means than their cu- 

 rious insertion into each other. These bony rings increase 

 in number with the age of the animal, and it is said that it 

 acquires an additional one at each casting of the skin. 



The habits of the rattlesnake are sluggish ; they move 

 slowly, and only bite when provoked, or for the purpose of 

 killing their prey. They have two kinds of teeth, viz. the 

 smaller, which are seated in each jaw, and serve to catch and 

 retain their food; and, secondly, the fangs or poisonous teeth, 

 which kill the prey, and are placed without the upper jaw. 

 These fangs constitute perhaps the most terrible weapons of 

 attack met with in the animal creation. The poison-teeth are 

 two in number, one fixed to each superior maxillary bone ; 

 when not in use, they are laid flat upon the roof of the mouth, 

 and covered by a kind of sheath formed by the mucous mem- 

 brane of the palate ; but when the animal is irritated, or about 

 to strike its prey, they are plucked up from their concealment 

 by muscles inserted into the upper maxillary bone, and stand 

 out like two long lancets attached to the upper jaw. Each 

 fang is traversed by a canal, not, as it is generally described, 

 excavated in the substance of the tooth, bat formed by bend- 

 ing, as it were, the tooth upon itself, so as to inclose a narrow 

 channel, through which the poison flows. The canal so 

 formed opens towards the base of the tooth by a large tri- 

 angular orifice, but at the opposite extremity it terminates 

 near the point of the fang by a narrow longitudinal fissure. 



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