AVES. 



337 



course, in the same manner as the vessels of 

 the uterus of the human subject. 



" There are no regular cmulgent arteries in 

 birds; the kidneys deriving their blood from 

 various sources, which will be pointed out as 

 they occur 



" The inferior extremity is supplied with two 

 arteries, which have a separate origin from the 

 aorta. One corresponds with the femoral ar- 

 tery, and the other deserves the name of ischia- 

 dic artery. 



"The ft moral artery (23, fig. 170, 171) is a 

 small trunk, which takes its origin from the side 

 of the aorta, opposite to the notch in the bones of 

 the pelvis immediately under the last rib. This 

 notch is formed into a round hole in the recent 

 subject by a ligament which is extended from it 

 to the rib ; and it is through this hole that the 

 femoral artery makes its exit from the pelvis; just 

 before it passes out upon the thigh, it sends oft" a 

 long branch (25), which runs backwards the 

 whole length of the margin of the pelvis, dis- 

 pensing arteries to the abdominal muscles on one 

 side, and the obturator internus on the other. 

 This branch also appears to supply one to the 

 oviduct. The femoral artery, immediately after 

 leaving the pelvis, separates into two branches; 

 one goes upwards and outwards, ramifying 

 amongst the muscles in that situation ; the 

 other turns downwards, and is distributed to 

 the flexors of the limb and round the joint, and 

 sends an artery to the edge of the vastus inter- 

 nus, which can be traced as far as the knee. 

 The kidneys appear to derive some irregular 

 inconsiderable branches from the femoral artery 

 while it is within the pelvis. 



"The ischiadic artery (26, fg. 166, 170) 

 is the principal trunk of the lower extremities, 

 exceeding very much in size the femoral. When 

 it is produced by the aorta, it appears to be the 

 continuation of that trunk ; the remaining part 

 of the aorta becomes so much and so suddenly 

 diminished, and seems, as it were, to proceed as 

 a branch from the back part of the vessel. 



" The ischiadic artery, while in the pelvis, is 

 concealed by the kidneys, in which situation it 

 gives a branch from its lower side, which di- 

 vides into three others that are distributed to 

 the substance of the kidneys ; one of these on 

 the left side is continued out of the kidney to 

 be lost upon the oviduct. The artery leaves 

 the pelvis by the ischiadic foramen in company 

 with the great nerve, while, within the foramen, 

 it gives a branch obliquely downwards under 

 the biceps to the muscles lying in the pelvis ; 

 and as it passes over the adductor it sends oft" 

 another along the lower edge of that muscle, 

 which is chiefly lost in the semi-membranosus. 

 It then detaches several small branches to the 

 muscles on the outer and fore part of the 

 thigh, some of which anastomose round the 

 joint witli the branches of the femoral artery. 

 Just as the ischiadic arrives in the ham, it 

 furnishes a very large branch downwards, 

 which divides into two ; one goes under the 

 gastrocnemius, to which and the deep-seated 

 flexors its branches are distributed as far as the 

 heel ; the other is analogous to the peroneal 

 artery ; it goes to the outside of the leg, sup- 



VOL. I. 



plies the peroneal muscles posteriorly, and 

 passes along the outer edge of the flexors of 

 the toes to the heel, above which, and behind 

 the flexor tendon, it divides, running on each 

 side of the heel, and forming several articular 

 arteries around the joint, and communicating 

 with the other branch, and with the anterior 

 tibial, and the metatarsal branch of the plantar 

 artery. 



" The articular arteries go off next from the 

 artery in the ham ; the two principal ones are 

 deep-seated. One proceeds under the vastus 

 internus to the external part of the joint; the 

 other is large, and situated upon the inside. 

 It forms two vessels : one is the true articular 

 artery, and spreads upon the ligaments of the 

 joint; the other is distributed in the substance 

 of the flexor of the heel, which is placed upon 

 the inside and fore part of the leg, and comes 

 out upon the edge of this muscle to be lost in 

 the integuments. 



" The posterior tibial artery (28, Jig. 171) 

 is extremely small; it only supplies muscular 

 branches to the internal head of the gastrocne- 

 mius, and some of the flexors of the toes ; it 

 is lost on the inside of the heel in anastomoses 

 with the peroneal artery, and other small 

 superficial branches. 



" The trunk of the artery of the leg now gets 

 upon the posterior surface of the tibia, and 

 sends off, through the deficiency left between 

 the tibia and fibula at the superior part, a 

 branch which is distributed to all the muscles 

 upon the fore part of the leg. The artery then 

 creeps along the back of the bones for some 

 way, and passing between them above, where 

 the fibula is anchylosed with the tibia, it re- 

 appears on the anterior part of the leg in the 

 situation of the anterior tibial artery; at this 

 place it detaches some very small branches, 

 which frequently divide and unite again, to 

 produce a most singular reticulation or plexus 

 of vessels, which closely adheres to the trunk 

 of the artery, and is continued with it as far as 

 the articulation of the tibia with the metatarsal 

 bone, where it disappears without seeming to 

 answer any useful design. This plexus resem- 

 bles in appearance exactly the division of the 

 arteries of the extremities, which has been 

 described by Mr. Carlisle in the tardigrade 

 quadrupeds, but differs from it in this cir- 

 cumstance, that the trunk of the artery is pre- 

 served behind it, without suffering any "material 

 diminution of its size. 



" The anterior tibial artery furnishes no 

 branch of any importance during the time it is 

 proceeding along the fore part of the leg. It 

 passes under the strong ligament which binds 

 down the tendons of the anterior muscles of 

 the leg, and over the fore part of the joint on 

 the inside of the tendon of the tibialis anticus, 

 at which places it distributes some brandies 

 which inosculate with the other arteries round 

 the joint ; it then pursues its course in the 

 groove along the anterior surface of the meta- 

 tarsal bone, and covered by the tendon of the 

 flexor digitorum. On coming near the foot it 

 sends oft' an artery, which divides, behind the 

 joint of the internal toe, into two branches ; 



