88 H. D. SENIOR 
of the distal part of the a. tibialis anterior which is developed 
between the stages of 15 and 16 mm. 
Branches. One of the adult rr. tarseae laterales represents 
the dorsal end of the r. perforans tarsi, all other branches are 
derived from the rete dorsale. 
A. femoralis. This artery arises from the a. iliaca externa 
between the stages of 11 and 12 mm. From the time of the 
first appearance of the femoral artery its growing end is bifur- 
cated into the r. communicans superius and the r. saphenus. 
The r. communicans superius traverses the hiatus tendineus and 
joins the a. axis between the stages of 12 and 14 mm., while the 
r. saphenus terminates below the region of the knee-joint. 
Branches. The A. profunda femoris seems to be derived from 
an arterial plexus which envelops the femur as early as the stage 
of 14mm. The proximal end of the artery is distinguishable at 
the stage of 22 mm. The a. circumflexa lateralis arises from the 
femoral trunk shortly before the stage of 14mm. Althoughthis 
artery is commonly regarded as a branch of the a. profunda, its 
original connection with the a. femoralis is frequently retained 
in the adult. The a. circumflexa medialis is not present at the 
stage of 22 mm. One of the a. perforantes, the first or second, 
is present at the stage of 22 mm., and is involved at that period 
of development in an extensive arterial plexus connected with 
the remainder of the distal part of the a. ischiadica. The other 
perforating arteries are not present. at the stage of 22mm. The 
a. pudenda externa is the only superficial inguinal branch present 
at the stage of 22 mm. The a. genu suprema corresponds to 
the part of the r. saphenus upon the proximal side of the origin 
of the rr. musculares and articulares. These branches arise 
directly from the a. femoralis, but have migrated to the em- 
bryonic r. saphenus by the stage of 22mm. The distal portion 
of the latter vessel corresponds to the r. saphenus of the adult. 
A. hypogastrica. The main stem of this artery represents the 
part of the dorsal root of the a. umbilicalis which lies beyond 
the place of origin of the a. iliaca externa. 
Branches. The anterior division of the a. hypogastrica is de- 
rived from the proximal part of the a. axis, which becomes the 
