962 THE OSTEOLOGY AND MYOLOGY OP THE DEATH ADDER, 



ligament, stretching between the tubercles representing the hjpa- 

 pophyses. Along with this mode of origin we have also a change 

 in the appearance of the muscles, which now have the appearance 

 of a number of quadrilateral plates, and these do not form such a 

 prominent column as when the muscles arise from the well deve- 

 loped hypapophyses. The muscles are separated from the internal 

 levatores costarum by the intercostal nerves ; while below or 

 internal to it is the vertebral fascia of the transversalis muscle. 

 These muscles are present in all the lizards that we have examined, 

 Hydrosaurus, Calotes, Rinulia, etc. 



St. George Mivart describes them in Menopoma alleghaniense^ 

 adding the remark that " the muscle gets thinner and smaller 

 backwards, but anteriorly it enlarges and passes in a fleshy mass 

 beneath the skull." He also describes them in Iguana tuherculata^ 

 while Sanders mentions them in Platydactylus japonicus. 

 Humphry describes them in Cryptohranchus and Pseudopus. 

 The lower part of the longus colli in higher animals shows us the 

 cervical representatives of these muscles. The arrangement of the 

 origin of different parts of this muscle may offer some explanation 

 as to the varying length of the hypapophyses. 



Subvertehral Rectus. 



The bundles of fibres which compose the subvertebral rectus 

 spring from the sides and the bases of the hypapophyses, and 

 running backwards and slightly outwards are inserted into the 

 parapophyses of the third vertebra from the origin. The bundles 

 are well marked in venomous snakes, but are but slightly 

 developed in the non-venomous forms. The muscles are separated 

 from the levatores costarum interni by the intercostal nerves ', 

 whilst they lie on the depressores costarum beneath. 



We can find no reference to a subvertebral rectus as occurring 

 in snakes, as it seems that this muscle has generally been taken 

 along with the levatores costarum interni. That it belongs to a 

 different group of muscles is evident from the relation of the 

 intercostal nerves to it. 



