938 THE OSTEOLOGY AND MYOLOGY OF THE DEATH ADDER, 



It is this muscle which acts slightly on the gland in venomous 

 serpents, while it is the masseter in the non-venomous. This 

 muscle is supplied by the same nerve as the parieto-pterygoid, 

 and we regard it as part of that muscle. In Diemenia there is 

 essentially but one muscle. We have changed the title of spheno- 

 to parieto-palatine, since the muscle arises wholly from the lateral 

 plate of the parietal in all the venomous forms that we have 

 examined ; while in Morelia it arises lower down, but even here 

 but few fibres are attached to the basisphenoid. In Python, 

 according to D' Alton, the muscle arises in great part from the 

 basisphenoid. The muscle in Daboia arises more anteriorly than 

 in Acanthophis, so that it comes to lie more in the orbital fossa. 



The muscle retracts the palatine and pterygoid bones, and also, 

 as mentioned above, acts on the mucous membrane of the fangs in 

 the Ela^ndcB ; this action being performed by the pterygoid in the 

 vipers. 



M. VOMERO-SPHENOIDEUS. 



M. vomero-sjyhenoideus, Hoffmann; Zuruchzieher des Vomer, 

 D'Alton ; M. spheno-vomerien, Duges and Duvernoy ; Prespheno- 

 vomerine f Owen, and R. Jones. 



The vomero-sphenoideus is a small muscle displayed on removing 

 the fascia from the roof of the mouth. It arises as a small belly 

 of muscle from a depression on the lateral plate of the parietal, 

 close to the basisphenoid. The muscle runs forward beneath the 

 trabecules cranii, and ends in a very fine tendon which is inserted 

 on the posterior end of the vomer. 



The muscle appears to be a differentiated portion of the pterygo- 

 sphenoideus. Its action is to depress and retract the premaxilla 

 through acting on the vomer. 



Some authors have stated that they consider the muscles con- 

 nected with the pterygoid and palatine bones of the snake to 

 have no analogues in other animals. The muscles certainly 

 present an extremely different aspect and function to the palate 

 muscles ; yet when we consider the extreme modification that the 

 bones have undergone, we cease to wonder at the change in the 



