MYOLOGY OF OPISTHOCOMUS CRISTATUS. 559 
Flexor carpi ulnaris is well developed. Origin similar to preceding muscles. 
Insertion into the ulnar carpal bone. Arising in conjunction with the latter, also from 
the olecranon of the ulna, is a moderately developed muscle, which is applied closely 
against the bases of the five or six posterior ulnar wing-feathers. ‘This terminates in a 
long fibro-elastic tendon, and is connected to the bases of the remainder wing-feathers as 
far as the carpus; this is the extensor carpi ulnaris. Immediately inferior to the latter 
is another elastic tendon, which connects the bases of all the wing-feathers together, its 
line of attachment corresponding to that of the integuments. It is strong, powerful, 
and as elastic as a piece of india-rubber. Its action is to approximate all the wing- 
feathers, and to maintain the carpus flexed on to the metacarpus. 
Flexor profundus digitorum.—Consists of two portions. The first arises from the 
proximal two-thirds of the inner or flexorial aspect of the ulna, and terminates in a 
common tendon, which grooves the carpus, and there divides into two tendons,—-a short 
and a radial one, which is inserted into the base of the distal phalanx of the Ist or rudi- 
mentary digit; the second or long one (internal to the preceding) goes to the distal 
extremity of the second or long digit. The second portion is the flexor metacarpi 
pollicis. 
It arises by fleshy fibres from the lower third of the ulna. It crosses obliquely over 
the lower end of that bone, terminating ina short tendon which grooves the outer portion 
of the carpus (the radial carpal). It is inserted into the superior and dorsal aspect of 
the carpus adjoining the rudimentary Ist digit. It is a powerful flexor of the carpus. 
Muscles on the superior border of the Radius. 
The eatensores carpi radialis longior et brevior are both closely associated at their 
origin, and receive, respectively, a tendinous slip from the extensor plice alaris. The 
distal tendons of these two muscles unite opposite the lower end of the radius, to be 
inserted into the base of the first metacarpal. The latter arrangement is common in 
many mammals, and is occasionally found in Man. 
The extensor ossis metacarpi pollicis arises from the posterior surface of the upper 
half of the shaft of the radius, and by a few fibres from the ulna. It is inserted by a 
slender tendon into the base of the 2nd metacarpal immediately posterior to the con- 
joined tendons of the extensors carpi radialis longior et brevior. A small rudimentary 
interosseous membrane intervenes between the extensor and flexor muscles. 
The extensor indicis arises from the lower half of the shaft of the radius (from the 
interosseous membrane) and from the adjoining portion of the ulna. It terminates in 
astrong tendon, which grooves the lower end of the ulna, crosses beneath the innermost 
tendon of the extensor communis digitorum to its ulnar side, and is finally inserted into 
the base of the 2nd phalanx of the 2nd digit. 
The extensor longus digitorum consists of two muscles, both of which arise from the 
external condyle. ‘The radial one terminates in a slender tendon, which is inserted into 
