Hal´lucal, a. Pertaining to the hallux.
Hal´lux, n. The hind toe. The name is retained, even when the hind toe is brought round to the front. When the toes are in pairs, it is the inner of the two hind ones, excepting in Trogonidæ. In the genus Picoides the actual single hind toe is not the hallux, but the fourth toe reversed, there being no hallux. This toe may always be recognized by presence of not more than two joints. It is the one usually wanting in three-toed birds, and is frequently rudimentary or functionless, even when present. Its large size, with largest claw, and specialization of its flexor muscle, marks the passerine or highest group of birds. (129.) (Sometimes written hallex or allex.)
Halo´nes, n. pl. Certain appearances of the yolk, probably due to the margins of its successive layers.
Ham´ulate, a. Hooked.
Ham´ulus, n.; pl. hamuli. Hooked fringe of a barbule; hooked barbicel.
Hand-quills, n. Primary remiges. (75.)
Has´tate, a. Spear-head shaped.
Head, n. (9, 29.)
Heel, n. (107.) See Calcaneus and Talus. Upper back part of tarso-metatarsus (tarsus or shank), rarely resting on the ground in birds when standing erect. (Commonly, but most improperly, called knee.)
Heel-joint, n. (103.) See Suffrago. The tibio-tarsal articulation, as it is called; that between the leg (crus), and the tarso-metatarsus (shank). With few exceptions among certain Raptores, it always bends backward; the knee always has its convexity forward.