114 The Alligator and Its Allies 



ventral part of the last rib that reaches the sterniuTi, 

 and extends with direct longitudinal fiber-bundles of 

 equal mass over the ventral third of the body back 

 to the pelvis. It is inserted as a fleshy tendon on 

 the anterior border of the pubis and more laterally is 

 united, together with the obliquus internus muscle, 

 chiefly to the last abdominal ribs which arise as an 

 ossification of the last strongly developed inscriptio 

 tendinea. This muscle-band, which unites with 

 that of the opposite side to form the linea alba, is 

 divided metamerically by seven distinct inscrip- 

 tiones tendinea. These inscriptiones are the above 

 described abdominal ribs which consist of bony 

 connective- tissue without a trace of cartilage cells. 

 These so-called abdominal ribs, then, are not true 

 ribs but are ossifications of the tendinous structures. 



II. From the anterior border of the os pubis 

 and the last strong inscription, also, to some extent, 

 as a process of the preceding part, begins a new 

 fleshy layer which, extending in diminishing size 

 backward, is inserted by a strong tendon on the 

 distoventral end of the ischium somewhat laterad 

 to the symphysis. It is the muscle that is called 

 by different authors the pyramidalis. 



III. Rectus lateralis. About in the region of 

 the twentieth vertebra, or at the level of the fifth 

 inscription, a fleshy band-like muscle separates 

 itself from the edge of the rectus muscle and the 

 obliquus internus muscle and passes over to fuse 

 with the ischio-coccygeus muscle. 



