76 H. D. SENIOR 
proximal and distal ends of the r. communicans inferior are 
respectively connected also take part in the formation of the 
a. peronaea. ‘ 
Of the branches of the a. femoralis, those arising from the 
lateral side are identical with the branches of the preceding 
stage. There are three branches upon the medial side. The 
recurrent branch (R in figures) seems to be identical with the 
similar branch of the preceding stage. It is doubtful whether 
the two other medial branches correspond to those observed in 
the preceding stage or not. 
g. Stage of 22mm C.I.C no. 1, figs. 8 and 9 G 
At this stage of development the continuity of the a. ischiadica 
has been interrupted and the a. femoralis alone conveys blood 
to the region beyond the knee. 
The femoral artery pursues a more direct course than before 
and gives origin to most of its important branches. In addition 
to the a. circumflexa lateralis which appeared at the stage of 
14 mm., it gives origin to the a. pudenda externa and the a. 
profunda. The r. musculo-articularis has migrated to the em- 
bryonic r. saphenus. The root of the latter branch, therefore, 
now appears as the a. genu suprema and gives origin to the r. 
saphenus and the rr. muscularis and articulares of the adult. 
The a. profunda arises from the a. femoralis quite close to the 
origin of the a. circumflexa lateralis. It seems probable that 
the embryonic a. profunda sometimes ar:ses from the root of 
the latter artery and sometimes directly from the femoral. In 
the former case the adult a. circumflexa lateralis would 
appear to arise from the a. profunda and in the latter from the 
femoral. The great variation in the site of the origin of the 
vessel is well known. 
The a. profunda femoris gives origin to one perforating artery 
which, since it pierces the adductores brevis and magus, repre- 
sents the first or second of the adult series. The single a. per- 
forans is connected, by means of an extensive plexus, with the 
more distal section of the now interrupted a. ischiadica. 
