1870.j MR.J. B. PERRIN ON BALEZNOPTERA ROSTRATA. 815 
it gave off a tendon to the index digit. From this tendon an addi- 
tional one was given off to the dorsal carpal fascia and the base of 
the middle metacarpal bone. Besides these it gave off three other 
tendons respectively to the second, third, and fourth digits. 
This muscle presented a few differences from the corresponding 
one described by Carte and Macalister, namely :— 
1. It attained a humeral attachment, whereas Macalister’s spe- 
cimen had only a radio-ulnar attachment. 
2. Its indicator tendon gave off an additional slip to the metacarpus. 
3. It was well developed, Macalister’s specimen being a mere 
rudimentary fasciculus. 
The flexor muscles are three in number—namely, flexor carpi 
ulnaris, flexor sublimis digitorum, and flexor profundus digitorum. 
The flewor carpi ulnaris (fig. 2, Flx. Carp. Ul.) arose from the 
olecranon, its ventral aspect, and was inserted into the ventral border 
of the lower end of the ulna. 
The flewor sublimis digitorum (fig. 2, Fl. I.) was a small and bi- 
" penniform muscle, occupying the interval between the ulnar and radial 
divisions of the profundus flexor. It arose from the distal end of the 
humerus, immediately below the insertion of the latissimus dorsi, and 
behind the aponeurosis from the masto-humeral. Its muscular fibres 
soon terminated in a long slender tendon, which passed downwards 
in the interval between those of the deep flexor tendons. Opposite 
the lower end of the radius it divided into’ two tendons: the radial 
tendon was short, and joined a corresponding tendon from the ulnar 
portion of the deep flexor; the ulnar tendon was also short, and 
terminated in the palmar carpal fascia. Between the divisions 
the radial tendon of the ulnar portion of the deep flexor passed, 
forming a rudimentary condition of perforatus and perforans. 
The flexor profundus digitorum (fig. 2, Flx. Rad. Digt., Flx. Ul. 
Digét.) consisted of two distinct portions, separated by the flexor sub- 
limis. The ulnar portion was fan-shaped, arising by fleshy fibres 
from the anterior surface of the distal end of the humerus, from the 
adjoining surface of the ulna and its olecranon, from the upper part 
of the shaft of the ulna and the strong fascia which covered it. It 
terminates in a strong flat tendon, fully half an inch wide, about the 
middle of the shaft of the ulna, and opposite the lower end of that 
bone divided into four tendons. The radial one passed through the 
two divisions of the flexor sublimis, joining the radial one, already 
described, to be inserted into the radial tendon of the deep flexor. 
The three remaining tendons were prolonged to the distal extremities 
of the phalanges of the second, third, and fourth digits respectively, 
imbedded in aponeurotic canals. The radial portion of the deep flexor 
was much smaller than the preceding: it arose from the upper two- 
thirds of the anterior surface of the shaft of the radius, and from the 
membrane occupying the interosseous groove. Its fleshy fibres ter- 
minated in a strong tendon, which was joined opposite the carpus by 
the conjoined tendon formed by the radial divisions of the sublimis 
and ulnar portion of the deep flexor tendons. The resulting tendon 
was finally inserted into the distal extremity of the first digit. 
