POISON APPARATUS OF VENOMOUS SNAKES 67 



important is the anterior temporal/ which arises from behind the orbit and 

 from the upper two-thirds of the firm fascia of the poison gland. Its fibers 

 run backwards over the gland and descend between it and the middle tem- 

 poral muscle. In this course the fibers lie posteriorly to the suspensory 

 ligament, and the outer ones, as they fold about the anterior end of the gland, 

 lie in contact with the prolongation of the external lateral articular ligament 

 upon the glandular body. Finally, the muscle winds around the commissure 

 of the lips, and is inserted into the mandible some distance in front of the 

 angle of the lips. The middle and posterior temporal muscles arise chiefly 

 from the temporal fossa and are inserted, one behind the other, into the 

 lower jaw. Their fibers descend nearly vertically and their obvious func- 

 tion is to close the jaw. The function of the anterior temporal muscle is 

 apparently twofold — to exert the pressure upon the poison gland and to aid 

 in shutting the mouth in the meanwhile. 



The poison gland of Crotalus occupies the side of the head, behind the eye 

 and beneath the anterior temporal muscle. Its posterior end extends three 

 or four lines beyond the commissure of the lips, while the anterior extremity 

 reaches below and just behind the eye. Thus situated, the gland is in rela- 

 tion with the bony surface behind the eye, with the middle temporal muscle, 

 with nerves which emerge under the suspensory ligament, and with the 

 anterior temporal muscle above and behind where that muscle descends to 

 its insertion. Beneath, the gland is in contact with the external pterygoid 

 muscle, with whose aponeurosis it has peculiar relations. The portion of 

 the gland below the anterior temporal muscle and above the line of the lip 

 is in direct contact with the skin, which is here loosely connected with the 

 areolar tissue. 



The ligaments of the poison gland are firmly connected with the tough, 

 fibrous capsule of the gland, and are really in continuation of the latter. 

 Anteriorly the ligament gradually tapers thin and runs forwards with the 

 duct, constituting a part of its thickness. Posteriorly there is one ligament 

 which attaches firmly upon the fascia of the temporal muscles. Another 

 strong ligament is found to extend from the capsule of the gland to the bony 

 surface beneath the gland. A third attachment of the gland is by means of 

 a fascia which forms a strong expansion upon the external pterygoid muscle 

 and then runs off laterally, to be inserted in the outer capsule of the gland. 



THE BITE. 



The mechanism of the bite has been studied most exactly and exhaustively 

 by Weir Mitchell, who made observations on the rattlesnakes. The snake 

 prepares itself for striking by raising the head a little above the rest of the 

 body, but not, usually, more than 3 or 4 inches, even in large snakes. The 

 neck and upper end of the trunk are not thrown into complete circle, but 

 lie in two or three abrupt curves across the mass of the coiled body. The 



1 M. temporalis anterior of Mitchell may be identical with M. masseter of authors, and his middle 

 temporal muscle with M. temporalis anterior of authors. 



