952 THE OSTEOLOGY AND MYOLOGY OF THE DEATH ADDER, 

 M. OBLIQUUS INTERNUS. 



M. cutaneus internus, Hoffmann ; Der innere oder untere 

 Bauchhautmuskel, D'Alton ; Innerer, schiefer BaucJwiuskel, 

 Heusinger. 



The internal oblique is composed of a number of " leaves " of 

 muscle, which arise from the external surface of the costal 

 cartilages ; and in addition a tendinous expansion spreads over 

 the pretrahentes costarum inferiores, constituting a lateral 

 portion of the muscle. The whole runs forward and inwards 

 towards the mid-line, the "leaves" of muscle widen by encroaching 

 on the lateral tendinous portion, and then fuse with the upper 

 layer of the rectus, which is differentiated to form the scutal 

 muscles; at the same time these "leaves" give rise to a tendinous 

 expansion internally, which fuses with the fascia of the trans- 

 versalis in the mid-line. 



"VVe do not find that an obliquus internus is described in the 

 snake by other writers ; the muscle " leaves " mentioned above 

 correspond, we believe, with portion of the rectus as described by 

 Humphry in Fseudojnis. We however think, after comparing 

 this muscle with the internal oblique of Hydrosaurus^ that we 

 have given its true homology. 



If we follow the internal oblique forward we find it converted 

 into the costo-mandibularis, or, as pointed out in the description of 

 that muscle, into a muscle which represents the sterno-hyoid group. 



M. RECTUS. 



Hautmusheln, Hoffmann, D'Alton. 



The rectus is represented by a large mass of muscle, which is 

 chiefly concerned in forming the scutal bundles. It consists of 

 two layers. The inferior is composed of a broad sheet of muscle 

 whose fibres run antero-posteriorly. This layer is inserted on to 

 the upper surface of the ventral scutes, and is continuous laterally 

 with the external oblique muscle. The superior layer is differ- 

 entiated into special bundles, which constitute the scutal muscles 

 proper. The several bundles occupy different planes, and have 



