522 ON THE ANATOMY OF PELECANOIDES. 
reach the sciatic artery, with which it then runs parallel to the knee. 
It crosses the femur on the inner side of that bone, and passes internal 
to the tendon of the femoro-caudal muscle, in such a way that on 
dissecting the subfemoral region (the femur being assumed to be at 
right angles with the tibia, and parallel with the ground) from the 
outer side of the thigh, after the biceps cruris is turned back, the 
femoral vein is seen to emerge from the anterior margin of the femoro- 
caudal tendon, quite close to its insertion into the femur. In Pele- 
canoides the femoral vein always runs eaternal to the femoro-caudal 
tendon, so that in the dissection just described it is seen to cross it, 
instead of being crossed by it. In no other Procellarian with which I 
am acquainted does this condition obtain; the only other bird in which 
LT have found a similar condition being Dacelo gigantea amongst the 
Alcedinidee.* 
* Vide “ Proceedings of the Zoological Sodiety,” 1873, p. 629. (Supra, p. 191.) 
