1870.] MYOLOGY OF PLATYDACTYLUS JAPONICUS. 419 
is inserted into the scaphoid bone of the carpus; it does not quite 
correspond to ext. carp. rad., but it does so more nearly than to any 
other extensor of the forearm. 
Extensor carpi ulnaris arises by two heads, one from the distal 
extremity of the outer condyle of the humerus, the other from the 
proximal half of the ulna; it is inserted into the pisiform bone and 
the base of metacarpal of the fifth digit. 
Letensor communis digitorum arises tendinous from the outer 
condyle between the last two muscles, and muscular from the whole 
length of the ulna, as far as its distal articulation; in the middle of 
the forearm it forms a thick fleshy mass, which soon divides into 
three broad tendons, which are inserted into the heads of the second, 
third, and fourth metacarpal bones; the one to the second sends a 
slip to be attached to the fascia covering the metacarpal bone of the 
pollex; in another specimen this part was divided into two, giving 
the appearance of five tendons instead of three. 
Interossei dorsales.—Each digit has two dorsal interossei, one on 
each side; they are inserted into the penultimate phalanx, being 
united together on the dorsum by a raphe ; this is a feature they all 
have incommon. Their origins are as follows :—The one on the ulnar 
side of the fifth digit arises from metacarpal bone of the same; that 
of the radial side from the tendon of the extensor digitorum, and 
also from the same metacarpal bone. The one on the ulnar side of 
the fourth digit arises from the same tendon with last, and also from 
its own metacarpal bone; the radial one of this digit from its own 
metacarpal bone. The one on the ulnar side of the third digit from 
the middle tendon of the extensor and its own metacarpal bone ; 
the radial one of this digit from the ulnar side of the head of the 
metacarpal bone of the second digit. The ulnar of the second digit 
from its own metacarpal bone and extensor tendon; its radial from 
the metacarpal bone of pollex in conjunction with the single one 
belonging to the latter. 
Extensor ossis metacarpi pollicis arises from the distal end of the 
ulna for one-fourth of its length, and passing across the forearm it 
is inserted into the whole length of the radial side of the metacarpal 
bone of the pollex. 
Extensor brevis digitorum arises from the bone of the carpus re- 
presenting the cuneiform, and immediately divides into five slips ; 
the first passes across the hand to be inserted into the base of the 
first phalanx of the pollex; each of the other four slips ends in a 
slender tendon, which is inserted into the penultimate phalanx of 
each of the other digits. 
Compleaus is the superficial muscle of the back of the neck. It 
is a distinct continuation forward of the longissimus and spinalis 
dorsi, and is inserted into the fascia covering the temporal muscle, 
into the supraoccipital and neural spine of the first vertebra, and 
also into the membrane which fills up the, space between the parietal 
and the supra- and exoccipitals. 
Trachelo-mastoid is a continuation forward of the longissimus 
dorsi. It also arises from the zygapophysis of the first cervical 
