Variation in the Muscles and Nerves of the Leg in Two Genera of Grouse (Tympanuchus and Pedioecetes)

by E. Bruce Holmes

Innervation.—The compound nerve formed by the fusion of a branch of the superficial peroneal nerve with a branch of the deep peroneal nerve gives a twig to the anterolateral edge of the muscle.

Individual Variation.—In some cases, the twig arises from the deep peroneal branch alone (which is not joined by the superficial peroneal nerve).

T. cupido

Individual Variation.—In one leg, some of the fleshy fibers arising from the first metatarsal insert independently on the medial surface of the trochlea for digit II (deep to the main part of the muscle).

P. p. jamesi

Individual Variation.—None of significance.

M. Extensor Brevis Digiti III (M. extensor proprius digiti III), [Figs. 19]E, [20]N

T. pallidicinctus

General Description and Relations.—Short and relatively broad (narrow proximally); on mid-anterior surface of distal part of tarsometatarsus; tendon of insertion fused with articular capsule.