928 THE OSTEOLOGY AND MYOLOGY OF THE DEATH ADDER, 



ticulierement, a maintenir le bol alimentaire pendant les con- 

 tractions que necessite Facte de la deglutition, et a faciliter son 

 cheminement a travers le canal alimentaire." 



After examining the subject attentively we certainly reject the 

 suggestion of Rochebrune with regard to the processes hindering 

 the regurgitation of the- food. We do not hesitate to say, that had 

 such been the case "selection" would in time have brought about a 

 much more efficient mechanism than at present exists in the poorly 

 developed hypapophyses of non- venomous snakes. In Deitrodon 

 alone have we not an example of how efficiently " selection " will 

 act when called upon 1 We prefer to adhere to the view that 

 the hypapophyses are developed to give attachment to muscles. 

 The question therefore arises, why should the hypapophyses disap- 

 pear in some species and not in others 1 The only explanation 

 we can give is that the hypapophyses are developed not only in 

 snakes, but also in the higher animals in the cervical and caudal 

 regions, while less commonly in the lumbar region; and that along 

 with the appearance of the hypapophyses we have well mcirked 

 hypaxial muscles developed. In the snake, while the hypaxial 

 muscles are developed throughout the whole column, yet we have 

 anteriorly the conspicuous bundles of the rectus capitis group 

 calling for much more extensive bony attachment than could be 

 affi)rded by the vertebrae without hypapophyses. In the venomous 

 snakes we find that the hypaxial muscular bundles do not flatten 

 out as in the non-venomous species, and this may be the reason 

 why we should always find greater processes. And going a step 

 further we say that the muscles remain more rounded in order to 

 act most efficiently, by aiding the rapid movements which charac- 

 terise venomous snakes. 



The Ribs. 



The rib consists of a shaft and two extremities. The inner 

 or vertebral extremity presents for examination an articular sur- 

 face and a well marked process. The articular face is reniform, 

 the concavity being anterior. Its superior portion is concave, and 

 articulates with the upper facet of the transverse process of the 



