v2 H. D. SENIOR 
The part of the a. tibialis posterior superficialis distal to the 
newly formed origin of the a. plantaris lateralis now becomes 
the a. plantaris medialis. The portion of the remainder of that 
vessel which is not concerned in the formation of the a. poplitea. 
becomes the a. tibialis posterior. 
The branches of the medial plantar artery anastomose, upon 
the lateral side of the foot, with the plantar rete, thus consti- 
tuting a (transitory) superficial plantar arch. 
The a. tibialis anterior, pars distalis, extends from the part of 
r. perforans cruris which lies in the extensor region of the leg to. 
the rete dorsale. The portion of the r. perforans which now lies 
beyond the proximal end of the pars distalis corresponds to the 
adult a. recurrens tibialis anterior. The portion which extends. 
from the a. poplitea profunda to the pars distalis enters into. 
the composition of the adult a. tibialis anterior. The a. recurrens. 
tibialis anterior is connected by means of a plexiform anastomosis, 
with the r. saphenus of the a. femoralis. 
Upon the medial side of the a. femoralis there are at this. 
stage three branches exclusive of the r. saphenus. Of these the 
most distal, which has a longer individual course than the others, 
takes a recurrent direction. The three branches break up to. 
form an extensive plexus (not indicated in the figures) which 
ramifies throughout the thigh and is particularly rich around. 
the perichondrium. It is probable that this plexus is eventually 
taken over by the adult a. profunda femoris and its branches. 
Two branches arise from the lateral side of the a. femoralis as. 
in the preceding stage. 
The a. glutaea superior now takes direct origin from the a. hy- 
pogastrica upon the proximal side of the origin of the a. ischiadica. 
f. Stage of 18 mm. C. 1. E. C., no. 409, figs. 6 and 9 F 
From the time of the junction between the r, communicans 
superius and the axial artery the caliber of the a. femoralis has. 
gradually exceeded that of the a. ischiadica, which has now 
become exceedingly slender. After having traversed the lower 
portion of the sacropudendal plexus, the a. ischiadica passes. 
