1909-10.] Short Muscles of the Hand of the Agile Gibbon. 217 
EXPLANATION OF PLATES. 
Plate I. 
The short muscles of the hand of the gibbon, slightly over the natural size. 
The different layers are shown as follows : — 1st, unshaded ; 2nd, moderately shaded ; 
3rd, darkly shaded. 
Ad.P. Adductors transversus and obliquus pollicis, or contrahens 1. 
F.P. Tendon of the flexor profundus digitorum to the thumb. 
F.B.P. Flexor brevis pollicis, both heads. 
A.P. Abductor pollicis. 
Op.P. Opponens pollicis. 
A.An.Lig. Anterior annular ligament cut. 
P. Pisiform bone. 
A.M.D. Abductor minimi digiti. 
F.B.M.D. Flexor brevis minimi digiti. 
Op.M.D. Opponens minimi digiti. 
P. 1 and P. 3. The first and third palmar interossei ; the latter muscle is only 
just seen, but its outline is dotted. 
C. 2, 3, 4. The second, third, and fourth contrahentes ; the first is Ad.P. 
D. 1, 2, 3, 4. The dorsal interossei according to their numbers 
M.A. 1, 2, 3, 4. The musculi interossei accessorii according to their numbers. 
Plate II. 
Fig. 1. The typical manus, after Cunningham. 
1, 2, 3, 4, 5. The metacarpal bones. 
D. 1, 2, 3, 4, 5, 6. The dorsal layer (abductores). 
M. 1, 2, 3, 4, 5. The intermediate layer (flexores breves). 
P. 1, 2, 3, 4. The palmar layer (adductores). 
D.U. The deep division of the ulnar nerve. 
S.U. The superficial division of the ulnar nerve. 
Fig. 2. The hand of the gibbon. 
Fig. 3. The hand of man (as I believe). 
Fig. 4. The hand of man as depicted in Quain’s Anatomy ; the diagram has in this 
case been reversed. The figures are the same for each. 
1, 2, 3, 4, 5. The metacarpals. 
D.I. 1, 2, 3, 4. The dorsal interossei. 
P.I. 1, 2, 3, 4. The palmar interossei. 
M.A. 1, 2, 3, 4. The musculi interossei accessorii. 
C. 2, 3, 4. The contrahentes. 
A.P. The abductor pollicis. 
Ad.P. The adductor pollicis. 
F.B.P. The flexor brevis pollicis. 
Op.P. The opponens pollicis. 
