114 The Alligator and Its Allies 
ventral part of the last rib that reaches the sternum, 
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. 
