Part 134

AT´ROPHY, n. See HYPERTROPHY.

ATTEN´UATE, a. Growing gradually slenderer toward an extremity; or, narrowly produced for a long distance; in neither case necessarily sharp-pointed, which would be rather acuminate.

ATTYP´ICAL, a. Of particular character acquired in specialization from a common type.

AUCHE´NIUM, n. Lower back part of neck; the scruff. (50.) (Little used.)

AU´RAL or AURIC´ULAR, a. Pertaining to the ear.

AU´RICLE, n. The external ear; wanting or imperfect in birds. Also, cavity (right and left) of the heart receiving blood from the system and lungs; also called atrium.

AURIC´ULARS, n. pl. Peculiar feathers overlying the ear-opening.

AUTOCH´THONOUS, a. Indigenous.

AUTOG´ENOUS, a. Literally, self-producing. In homology, developing from distinct and independent centres. Opposed to exogenous.

AU´TOPSY, n. Personal observation or examination.

AUTOP´TICAL, a. Personally inspected.

AUTUM´NAL PLUM´AGE. That ensuing from the first moult, if any, or prior to the spring moult, from which it is different in many birds.

A´VIARY, n. Place where birds are kept captive.

AVIC´ULA, n. Little bird; hence, nestling, fledgling, or any ungrown bird.

AVICUL´TURE, n. Care of birds.

A´VIS, n.; pl. aves. Bird.

AXIL´LA, n. Armpit; hollow beneath the shoulder. (78.)

AX´ILLAR or AX´ILLARY, a. Pertaining to the armpit.

AX´ILLARIES, n. pl. Lengthened or otherwise distinguished feathers growing from the axillary region. (81.)

AX´IS, n. Second cervical vertebra. Also, an imaginary line passing along the middle of any one of the three mutually perpendicular planes of the body, the longitudinal, vertical, and transverse. Also, a pivot.

A´ZYGOS, a. Single, in the sense of not paired.

BACK, n. Upper surface of body proper, corresponding to dorsal and sacral vertebræ. Includes INTERSCAPILIUM and TERGUM (which see). (57.)

BACK OF NECK. Cervical region. Includes NUCHA and CERVIX (which see). Equivalent to hind-neck. (48.)

BACK OF TAR´SUS. Hinder edge and hinder half, on each side, of tarsus. See PLANTA. Homologically the sole. (106.)

BAND or BAR. Any crosswise color-mark, transverse to long axis of the body.

BAND´ED or BARRED, a. Marked crosswise.

BARB, n. Any one of the laminæ composing the vane of a feather.

BAR´BA, n. Beard. Lengthened or otherwise distinguished feathers of chin or throat.