354 Contributions to the 



more extensive than in man. On the upper surface of 

 part of the parietal and frontal portions of the Occipito- 

 frontalis may be seen a thin layer of muscular fibres, about 

 two inches in width, near the sagittal suture, thence con- 

 verging downward towards the ear. If this represents the 

 Attollcns aurcm, it is much more extensive than in man. 



Cutaneous muscles. In the Chimpanzee, as in the Go- 

 rilla and Orang, the Platysma myoides is rather thicker than 

 in man, but I could find no cutaneous muscles upon the 

 trunk as in the lower animals. There was a distinct Der- 

 mo-lmmeralis in each of the two Cynocephali and three 

 Macaci which I dissected, and it is not mentioned as ab- 

 sent in the others. It is generally inserted over the ten- 

 don of the Latissimus dorsi, and would thus serve either 

 to wrinkle the skin, or to assist the latter muscle to flex 

 the humerus, as in climbing. 



Digastricus. The anterior belly is much broader than 

 in man,- being composed of two portions, — one external, 

 next the jaw bone, rounded and more directly connected 

 with the tendon, — the other internal and twice as broad, 

 reaching to the middle line to join that of the opposite 

 side. The two muscles fill the space between the rami of 

 the jaw. 



Sterno-mastoid. Wholly distinct from Clcido-mastoid. 

 Occipital portion very broad, the aponeurotic attachment 

 reaching from just behind the ear to the middle line on the 

 superior occipital crest. Thence downward it gradually 

 becomes narrower, thicker, and more rounded, crossing the 

 Clcido-mastoid to be inserted by a short, round tendon 

 into the manubrium, as in man. 



Clcido-mastoid. This is smaller than the preceding, and 

 the reverse in shape, the small end being above, and at- 

 tached to the skull just within tiie anterior edge of the 

 Sterno-mastoid^ while the lower end is wider and inserted 

 into the upper border of the clavicle, near the sternum. 

 In the Gorilla, according to Duvernoy, the sternal portion 



