378 Contributions to the 



Flexoris longi digitonim. The disposition of the tendons 

 of this muscle, and of the Flexor long-us pollicis, is various 

 in different individuals and species. 



Flexor longus pollicis. This is a large, strong muscle 

 arising as in man and continuing fleshy to the joint, where 

 it forms a broad tendon which divides into three, which are 

 inserted into the distal phalanges of the first, third, and 

 fourth toes, as in the Chimpanzees of Vrolik and Traill, and 

 in Duvernoy's Gorilla ; the tendon of the first toe passes 

 through a separate strong loop at the base of the meta- 

 tarsal bone. In Owen's Orang the great toe received no 

 tendon from either of the long flexors, but in the Howl- 

 ing-Monkey the great toe received the single tendon 

 of the Flexor longus pollicis. In dissecting the Ateles 

 Paniscus, both Mr. Folsom and myself at first described 

 this muscle as the Flexor longus digitorwn, being deceived 

 by its great size, and the number of its tendons. The 

 tendons of the two muscles before their subdivision are 

 firmly connected by a whitish substance. As in Owen's 

 Orang, bending the foot up against the leg caused a me- 

 chanical flexion of the toes which would materially in- 

 crease the firmness of the foothold upon a branch. 



Flexor brevis digitorum. Arises as in man, but has only 

 two tendons, which are inserted into the middle phalanges 

 of the second and third toes. 



Flexor accessorius. Has but one, the external head, 

 which is joined to the outer border of the Flexor longus 

 digitorum. Both this and the Flexor brevis vary consider- 

 ably in different species, and also in different Chimpanzees. 



Lumbricales Flexoris longi digitorum. Three fasciculi 

 arising upon the tendon of the Flexor longus digitorum; 

 the inner one is attached to the inner border of the first 

 phalanx of the second toe, the middle one joins the tendon 

 of the Flexor brevis, to be inserted into the second pha- 

 lanx of the third toe after being perforated by the tendon 



