268 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
digits. This divides into four tendons, two large and two small; the 
two large ones, after passing through the sheaths formed by the perfora- 
tus, are inserted into the ungual phalanges of digits three and four ; the 
two smaller tendons are attached similarly to the second and fifth digits. 
As regards the innervation of the normal manus, we need concern our- 
selves with the condition of the median nerve only, by which the digits 
--]-------\ ------flz. perf.’ 
Lar flac. perf. 
Fic. J. —Left normal manus of pig, showing flexor muscles. lz. perf., tendons of 
flexor perforatus; fla. perf’., flexor perforans. 4% natural size. 
are chiefly supplied. The trunk of the median nerve (Fig. J, n.m.) 
passes between the two flexor muscles at the carpal joint ; nearly at a level 
with the proximal ends of metacarpals 11 and v it gives off two lateral 
branches (2, 5) to supply these digits. The main nerve, continuing dis- 
tally, soon separates into two large branches (3, 4), which pass 
together along the region between digits 11 and tv, to which they 
are distributed. The lateral branches (2, 5) before passing to their 
