Comparative Myology of the Chimpanzee. 377 



passed through a separate loop just in front of the astra- 

 galus. In a small Macacus now before me, the real annu- 

 lar ligament is attached to the fibula higher than to the 

 tibia, and not at all to the calcaneum ; and there is also a 

 perfect loop for the Extensor dig-itorutn, of which both 

 ends are attached close together on the upper border of the 

 calcaneum. This loop is one third of an inch long, and 

 freely movable after the fascia has been taken away. I 

 should think that the position of the annular ligament 

 wholly above the joint, and of this extra loop wholly be- 

 low, would better enable the muscle to act, not only as an 

 extensor of the toes, but also more freely as a flexor of the 

 foot, when also the insertion of the loop on the outer edge 

 of the calcaneum would perhaps supply the place of the 

 Peroneus tertius. 



Peroneus tertius. So far as I know, this has been found 

 in the Quadrumana only once, in the Howling- Monkey 

 by Prof. Wyman, where, however, instead of being a 

 flexor of the foot, it passed beneath the outer malleolus, 

 and was inserted into the base of the little toe, which it 

 would serve to extend. 



Extensor proprius poUicis. Probably present, though I 

 neglected to make a note of it ; on the right side as in 

 man. 



Tibialis posticus. Origin and insertion apparently as 

 in man, but I saw no sesamoid bone near the insertion 

 In Owen's Orang it was inserted into the internal cunei- 

 form, and in Ateles Paniscus into the scaphoid bone only. 

 It is usually more slender than in man. 



Flexor longus digitorum. Arises as in man, but con- 

 tinues fleshy to the ancle, below which it divides into two 

 tendons, which are inserted into the distal phalanges of 

 the second and fifth toes. The Musculus accessorius is 

 inserted into the external border of this muscle, and from 

 the tendon arise the three fasciculi of the Lumbricales 



JOOKNAL B. S. iN. H. 48 AUGUST, 1861. 



