BY W. J, UcKAY. 975 



the maxilla this bone moves slightly on the prefrontal, which in 

 turn moves forward and upward, since it is articulated by a joint 

 with the frontal. 



Mitchell says that the spheno-pterygoid alone erects the fangs 

 by acting on the pterygoid, but this is an error, as the parieto- 

 pterygoid shares largely in this action. 



The snake is now ready to strike. With head firmly fixed, 

 mandibles depressed, and fangs erect, the blow is struck by 

 the sudden contraction of the rectus capitis anticus group 

 of muscles, which are attached to the processes on the basi- 

 occipital, and also by the contraction of the sacro-lumbalis group 

 prolonged to the side of the basioccipital. The fangs enter 

 in a downward and outward direction, and the jaw is closed by the 

 contraction of the masseter, temporal, external pterygoid, and 

 parieto-mandibularis muscles, along with which action the poison 

 is injected through the contraction of the masseter on the gland. 

 The squeezing of the gland is brought about thus : — the superior, 

 or superficial, portion of the masseter contracting, pulls forward the 

 posterior extremity of the gland ; this action, however, is opposed 

 by the strong zygomatic ligament attached to the gland externally 

 and posteriorly. If now the inferior portion of the masseter con- 

 tracts, the gland will be pulled downwards ; this is opposed by the 

 suspensory ligaments and by the integument below and externally 

 made tense by the contraction of the retractor oris muscle ; and 

 also by the internal pterygoid, which is now contracting in order 

 that it may pull the fangs more deeply into the wound. Thus 

 opposed on all sides the gland is squeezed by the masseter most 

 effectually. Now that the fangs are deeply sunk in the wound, 

 and the solid teeth of the palatine are also driven in, the snake, if 

 it no longer wishes to hold its prey, proceeds to extricate its teeth. 

 This is not always an easy matter, and frequently the head is 

 rotated from side to side in order to loosen the too firm hold. 

 This rotating action is evidently largely aided by the insertion of 

 the longissimus and sacro-lumbalis groups in the skull. If, how- 

 ever, the snake can disengage itself without any difficulty, it does 



