VEINS OF BIKDS. 205 



myelonal sheath, and these appear to dispose of their blood 

 gradually, as they descend in the neck, by means of lateral com- 

 munication mth the vertebral veins. The superior longitudinal 

 sinus is continued at its anterior part under the frontal and nasal 

 bones, and anastomoses with the ophthalmic and nasal veins. 

 There are other small sinuses in the several duplicatures of the 

 dura mater. 



The veins of the icings, which are derived from the parts within 

 the chest, the muscles about the scapula, and the pectoral muscles, 

 accompany jthe arteries of the same parts so regularly that their 

 course does not require description. 



The axillary/ vein, fig. 94, I, lies considerably lower in the axilla 

 than the artery, but still continues to receive corresponding 

 branches {m indicates the great pectoral vein). The trunk of 

 the vein descends in the course of the humeral artery, but more 

 superficially ; in this situation it may be called the humeral vein, 

 ib. n. Branches of this vein accompany the articular and 

 profunda arteries, and at the middle of the humerus a large 

 branch of the vein enters the bone ; there are also two very 

 small branches which lie in close contact with the humeral artery, 

 which they accompany nearly its whole length. 



The principal vein of the wing di\ddes into two, opposite to 

 the joint of the humerus with the fore-arm. One of these 

 branches, ib. o, belongs to the sides of the radius ; it receives 

 blood from the muscles and skin on the upper part of the fore- 

 arm, but its chief vessels lie between the integuments of the fold 

 of the Aving. The other branch of the humeral vein, ib. p, crosses 

 the fore-arm, just below the articulation, in company with the 

 nerve, and running along the inferior edge of the ulna, receives 

 a branch from between the basis of each quill, is continued along 

 the ligament which sustains the rest of the quills to the extremity 

 of the wing, recei\dng many veins of the joints from the opposite 

 side of the fingers. Besides these large superficial veins of the 

 fore-arm, there appears to be one, and sometimes two, small 

 accompanying veins to the ulnar and interosseous arteries, ib. q. 



The inferior vena cava, ib. K, before it enters the auricle. A, re- 

 ceives as usual the hepatic veins, ib. s; these are numerous, and open 

 into the cava as it passes behind the liver, or more frequently 

 within the substance of that viscus in the back part. 



The trunk of the vena cava is very short in the abdomen ; it 

 separates into two great branches analogous to the primary iliac 

 veins, ib. t, opposite to the adrenals ; these turn to each side, and 

 experience a very singular distribution. On coming near the 



