OCR Text |
Show 1881.] OF CERCOPITHECUS CALLITRICHUS. 815 side of the tendon of the flexor profundus for the pollex, and is inserted into the base of the terminal phalanx of that digit. The aB-ductor, adductor,and opponenspollicis are well developed ; the flexor pollicis Brevis smaller, and quite concealed by the aBductor pollicis. These last four muscles are quite distinct from the small muscle above described, which arises much higher up, and the tendon of which passes forwards superficial to all. It is difficult to trace the homology of this muscle, which corresponds in its insertion to that of the flexor pollicis longus of human anatomy, but differs altogether in its origin. Is it a separated part of the aBductor pollicis or of the flexor pollicis Brevis 1 The aBductor minimi digiti is very large, arising by two heads, one from the pisiform bone, the other from the annular ligament in common with the flexor minimi digiti; both unite to form a round tendon, which has the usual insertion. Flexor minimi digiti is also well developed, and larger than the flexor ossis metacarpi minimi digiti. The four lumBricales are well developed ; they arise together from the palmar surface of the yet united four inner tendons of the flexor digitorum profundus. Cercopithecus ca llitrichus. Flexor muscles of right foot, ad. J. ft. br. Flexor digitorum brevis; fl. ace. flexor accessorius; I, I, I. lumbricales ; fl. long. dig. flexor longus digitorum (distr. to second and fifth toes); fl. long. hall, flexor longus hallucis (distr. to first, third, and fourth toes); pi. tendon of plantaris. In the foot the flexor digitorum brevis tendon for the second digit arises from a bundle of muscular fibres having their origin wholly from the expanded plantaris tendon ; lower down it is joined by a few muscular fibres arising from the tendon of the flexor digitorum longus (fig. 1.), the other flexor brevis tendons having their origin from muscular fibres arising from the conjoined tendons of the flexor digitorum longus and flexor hallucis longus. Tbe three lumBricales are well developed and have the same mode of origin in both feet, arising from the inner sides of the flexor tendons for the three outer toes, into which they are inserted. The transversus pedis is present, but instead of arising, as in the human foot, from the extremity of the fifth metatarsal bone, arises from that of the second and by a fascial aponeurosis from the shaft of the third (fig. 2). |