CROTALUS HORRIDUS. 



The gland wherein the poison is elaborated occupies the 

 greater part of the temporal fossa, and is inclosed in a white 

 and tendinous capsule ; the substance of the organ is spon- 

 gy, and composed of cells communicating with its excretory 

 duct, by which the venom is conveyed to the opening at the 

 base of the fang. The poison-gland is covered by a strong 

 process of the temporal muscle, which is attached to a thin 

 aponeurotic line. The greater portion of the fibres of this 

 muscle take their origin from* the capsule of the secreting 

 apparatus, which they partially envelop, and then, winding 

 round all the posterior part of the gland, and passing behind 

 the commissure of the lips, the lower part of the muscle is 

 firmly implanted into the lower jaw very far anterior to the 

 angle of the mouth. The process of the temporal muscle 

 which thus surrounds the gland is very thick and strong, so 

 that it is easy to imagine with what force the poison will by 

 this mechanism be injected into the wounds inflicted by the 

 fangs, seeing that the same muscles which close the jaw at 

 the same time compress the bag of venom with proportion- 

 ate energy. 



M. Duvernoy, who has devoted much time to the study of 

 the organization of venomous serpents, has ascertained, that, 

 besides the venomous teeth in front, the existence of which 

 has long been known, they have, in the hinder part of the 

 jaw, longer and stronger teeth, of as great malignity. He is 

 also inclined to the opinion, that the secretions of the lachry- 

 mal glands, in some descriptions of venomous serpents, do not 

 go to moisten the eyeballs, but enter the mouth, and assist in 

 communicating saliva to the food. 



Behind the large poison-fang in use, the capsule that in- 

 closes it generally contains the germs of several others, ready 

 to supply its place should the former be broken off; and in 

 the event of such an accident, one of these supplementary 

 teeth soon becomes consolidated with the superior maxilla, 

 and adapted in all respects to take upon itself the terrible 

 office of its predecessor. 



Dreadful as are the means of offence thus conferred upon 

 the poisonous serpents, it is impossible to avoid noticing in 

 this place that admirable provision of Nature, which, in one 

 genus at least, serves to give timely warning of the vicinity 

 of such dangerous a'ssailants. It is only necessary to men- 

 tion the rattle of the animal under consideration ; an organ 



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