378 REPORT OF NATIONAL MUSI^JM, 1893. 



tlie purpose of the blow. The closure of the jaw is el't'ected by the posterior, midtlle, 

 au(l auterior teru])or!il iniuscles. The first, two tend simply to shut the mouth; the 

 anterior temporal, however, is so fohUid about the poison gland that while it draws 

 up the lower jaw it simultaneously compresses two-thirds of the body of the gland. 

 This force is applied in such a manner as to squeeze the lluids out of the upper and 

 back parts of the gland and drive them forward into the duct. The anterior lower 

 angle of the gland, as well as a portion of the duct, is subjected to similar pressure 

 .at the same instant, owing to the Hat tendinous insertion of a part of the external 

 l)terygoid upon the parts in question. 



It will thus be observed that the same muscular acts which deepen the wound fix 

 the prey, and inject the venom through the ducts and into the tissues penetrated by 

 the teeth. The whole process here described at such length is the work of an 

 instant, and the serpent's next etfort is to disentangle itself from its victim. This 

 step is effected by relaxing the muscles of the neck so as to leave the head passive, 

 while the continued traction of the muscles of the body pull upon it, and thus with- 

 draw the fang, over which glides the elastic mucous sheath as the pterygoid, again 

 acting, depresses the fang, and the serpent recovers its posture of defense. 



It happens, not infreciuently, that the teeth of the lower jaw catch in the skin of 

 the bitten animal, and thus prevent the snake from retreating at once. When this 

 takes place the serpent shakes its head from side to side with a motion whicli so 

 nearly resembles the shake a dog gives its prey that it has been mistaken by at least 

 one observer for an expression of rage. It is really an attem])t to escape; nor is it 

 always successful, since a large animal will often drag a snake until the fangs them- 

 selves break loose and are left in or on the bitten part. 



In considering this portion of our subject it is well to notice what has been too 

 much overlooked, the fact that, while the snake commonly employs both fangs, it 

 does often inflict but a single wound. When obtaining venom from living snakes, 

 I have been accustomed to allow them to bite upon the inner edge of a cup, and I 

 have observed that on some occasions both fangs were used at once, and that on 

 others only one was active. Or, the fangs Avere used in succession, an appreciable 

 interval of time intervening. If this occur when a snake at freedom strikes an 

 object, it is, of course, possible that the animal may escape before the. second fang 

 is driven in by the traction of its proper external pterygoid muscle. At all events, 

 it is certain that these facts should receive due appreciation in estimating the dan- 

 ger of a given bite and the value of an antidote. 



There remains for consideration one muscular motion, which I have observed to 

 accompany the effort to bite when the snake is held by the back of the neck. It 

 consists in a turning outward of the points of the fangs, so as to separate them 

 from one another.* This divergence of the fang points is disadvantageous, inas- 

 much as it causes them to enter somewhat obliquely, and frequently throws one 

 fang beyond the part bitten, when that part happens to be small. It has a use with 

 reference to the snake itself, since the fang point.s, when thus widely separated, lie 

 oustide of the lower jaw, and are thus prevented from wounding it. This purpose is 

 greatly aided by the.action of a muscle analogous to the mylo-hyoid, which approxi- 

 mates the anterior extremities of the low^er maxillary, or numdibular bones, so as 

 to make narrow the extremity of the jaw. The protection thus obtained is very 

 essential, since the serpent always closes the jaw violently when biting, but does 

 not always succeed in seizing its prey. Whether or not this divergence of the fang 

 points occurs when the snake bites unrestrainedly, I can not say, but as I have been 

 very often astonished at the distance between the wonnds, when both fangs had 

 taken effect, it is highly jirobable that it occurs under all circumstances. 



The power with which the venom is ejected from the tooth depends somewhat 

 upon the amount contained in the gland and its ducts. When the snake fails to 



* I could not determine whether this divergence took place when the snake, at 

 freedom, struck an animal. 



