1896.] ANATOMY or PETROGALB XAJfTHOPUSj 705 



The Thyroid body consists of two separate oval lobes about 

 I inch long, lying one on each side of the trachea without any 

 isthmus connecting them. 



The Arch of the Aorta has only two branches, the innominate 

 and the left subclavian ; the former gives off the right subclavian, 

 soon after which it divides into right and left cnrotids. 



The Subclavian arteries pursue a normal course and give off 

 vertebral, internal mammary, and transverse cervical branches, but 

 no inferior thyroid or superior intercostal were seen. The common 

 Carotid gives off the superior thyroid and, at the anterior margin 

 of the larynx, divides into external and internal carotids, the 

 former giving off lingual, facial, and occipital branches, and 

 ending almost entirely in the internal maxillary, the temporal 

 being very small. The superior laryngeal branch comes off from 

 the lingual. 



The Axillary artery gives off well-marked thoracic, subscapular, 

 and circumflex branches. The Brachial gives off a small superior 

 profunda which accompanies the musculo-spiral nerve, as well as 

 a large nutrient branch to the humerus. About the middle of the 

 arm, at the place where the median nerve is finally formed, a 

 superficial branch comes off, which possibly represents the inferior 

 profunda though it does not accompany the ulnar nerve. The 

 brachial artery then passes through the supra-condylar foramen, 

 after which it gives off some muscular branches and soon divides 

 into posterior interosseous and median. 



The posterior Interosseous passes to the back of the forearm 

 between the two bones, giving off a large posterior interosseous 

 re(;urrent branch ; while the median accompanies its nerve into the 

 ])alm of the hand, where it divides into four digital branches for 

 the clefts between the digits. There is no radial or ulnar artery 

 and no deep palmar arch. Owen' describes the artery which I 

 have called median as the ulnar, and says that there is also a 

 radial artery. 



The Thoracic aorta shows nothing worthy of special notice. 



The Abdominal aorta gives off the cteliac, mesenteric, and two renal 

 arteries close together, just behind the opening in the diaphragm. 

 Of the two renals the right is a little in front of the left. There is 

 no posterior mesenteric artery, a condition which Owen has noticed 

 in all Marsupials. The aorta trifurcates opposite the disc between 

 the fifth and sixth lumbar vertebrae into the caudal and two 

 external ihacs. The internal iliacs are given off from the caudal 

 opposite the posterior part of the sixth lumbar vertebra, as has 

 been pointed out by Owen. 



The External Iliac gives off a large ilio-lumbar branch, and, just 

 before reaching the brim of the pelvis, a common trunk, which 

 divides into obturator and deep epigastric. 



The Common Femoral soon after its commencement gives off an 

 external circumflex branch, which runs outward between the super- 



' ' Anatomy of Vorlebrat«o,' yol. iii. p. 541. 



