42 THOMAS DWKiHT OX 



toe. The second ami tliird are extra niuscle.s, each arising from mw side ol' the third 

 metatarsal and inserted into rither side of tlie phalanx. The fourtli passes from the 

 tibial side of the fourth metatarsal to its phalanx. The fifth arises from the fibular side 

 of the fourtli metatarsal and is attached to both the fourth and fifth toes as is the dorsal. 

 It differs from it by arising only from the fourth metatarsal. This excessive redundancy 

 of interosseous muscles in the foot has not, I believe, been observed. 



Heart. 



The heart and great vessels, removed with the lungs, were in the center of a mass 

 of disease intensely repulsive. At my request a veteran dissector undertook to make a 

 careful dissection of the roots of the lungs and the chief vessels. He was obliged after 

 several hours' work to give up the task. The heart was therefore cut ol¥ from the rest. 

 The left auricle was cut so close that nothing of the pulmonary veins is to be seen. 

 The branches of the aorta could not be followed. Their identification is, however, from 

 the manner of their arrangement, practically certain. 



The length of the heart (after preservation in alcohol) is 11.5 cm. and its breadth 

 al)Out 8 cm. The external appearance is not unlike that of the liinnan heart. It seems 

 relatively broader, and the origin of the aorta is less concealed by the pulmonary artery. 

 The conus arteriosus is well marked; so are also the auricular appendices. The arch of 

 the aorta gives off first an innominate artery about 1 cm. long which divides into the 

 rio-ht subclavian and the right carotid. After an interval of 2 mm. the left carotid and 

 the left subclavian arise close together, so close as at first to suggest a second innomi- 

 nate. A minute vessel springs from the aorta just in front of the intej'space between the 

 innominate and the left carotid, very probably a thyroidea ima, since Sutton has seen this. 

 The subclavian arteries are much larger than the carotids, the lumen of the right sub- 

 clavian being nearly 6 mm. in diameter and that of the right carotid less than 4 mm. 

 Both these vessels on the right side are a little larger than their fellows of the left. 

 Gratiolet and Alix, while noting this discrepancy between subclavians and carotids in the 

 T. aubryi, comment on the relatively small size of all the four great arteries. In this sub- 

 ject the carotids seem to me relatively as large as in man, and the subclavians relatively 

 laro-er. The diameter of the lumen of the aorta iunnediately after the origin of the left 

 subclavian is about 1 cm. 



Dr. Arthur Keith' finds accounts of the origin of the great vessels in eleven chim- 

 panzees. In seven the plan was as in man. In three the left carotid sprang from the 

 innominate. This, it may be noted, is not an uncommon arrangement in man. In one 



' Jouni. anat. phy.siol., vol. 29. 



