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.
HEEL-PAD, _n._ (115.) Pterna; tuber (which see). The posterior portion
of _pelma_, immediately under the foot-joint, and frequently prominent.
(But _heel-pad_ should not be used in this connection, since the _heel_
(_calcaneus_) is at the top of the tarsus, and not at the bottom where
the _heel-pad_ lies.) (115.)
HEMI- (_in composition_). Semi-; demi-; half.
HEPAT´IC, _a._ Pertaining to the liver; as, _hepatic_ artery, _hepatic_
secretion.
HETEROGE´NEOUS, _a._ Of different or dissimilar nature; of mixed or
miscellaneous character.
HEX´AGON, _n._ Figure of six sides and six edges.
HEXAG´ONAL, _a._ Having six sides and edges.
HIBER´NAL, _a._ Pertaining to the winter time. (Neither this nor
_æstival_ are much used, although _vernal_ and _autumnal_ are
continually employed.)
HIND-NECK, _n._ (48.) See CERVIX.
HIND-TOE, _n._ (129.) See HALLUX.
HINDER PARTS. (8.) See URÆUM.
HIP, _n._ Joint of femur with pelvis; projection formed by femoral
trochanter over the joint.
HIRSUTE´, _a._ Hairy; rather shaggy, as the feet of a grouse.
HISTOG´ENY, _n._ Formation of tissue.
HISTOL´OGY, _n._ Minute anatomy; history of tissue.
HISTON´OMY, _n._ Laws of formation of tissue.
HOAR´Y, _a._ Of a pale silvery-gray.
HOLORHI´NAL, _a._ Having the nasal bones contiguous.
HOMOGENE´ITY, _n._ Sameness; structural similarity.
HOMOGE´NEOUS, _a._ Of the same kind or nature. Opposed to
_heterogeneous_. A _homogeneous_ group contains only structurally
related forms.
HOMOLOG´ICAL, HOMOL´OGOUS, _a._ Structurally related; having structural
affinity. Opposed to _analogous_, which implies similarity of
appearance, purpose, or use without corresponding affinity.
HOMOL´OGY, _n._ Structural affinity, generally implying genetic
relationship. Opposed to _analogy_, or mere resemblance.
HOMOTYP´ICAL, _a._ Of the same type of structure.
HOMOT´YPY, _n._ A particular kind of homology.
HOR´NOTINE, _a._ or _n._ Yearling; a bird of the year.
HU´MERAL, _a._ Pertaining to the humerus, or, more generally, to the
upper arm.
HU´MERUS, _n._ The upper arm bone; sometimes the whole upper-arm, from
shoulder to elbow.
HY´ALINE, HY´ALOID, _a._ Transparent, like glass; said chiefly of the
vitreous humor of the eye, and of certain appurtenances of the back
chamber of the eye.
HY´BRID, _a._ or _n._ Cross-born between two species; mongrel.
HYBRIDIZA´TION, _n._ Cross-fertilization. Production of hybrids.
HY´BRIDIZE. To cross and bear mongrel offspring.
HY´OID, HYOID´EAN, _a._ Pertaining to the _os hyoides_ or tongue-bone,
or, more generally, to the tongue itself.
HYPAPOPH´YSIS, _n._ Bony process from the under side of a vertebra,
sometimes very large, as in the loon.
HYPER- (_in composition_). Same as _super-_ (which see).
HYPERBO´REAN, _a._ Northern; boreal.
HYPERCHROM´ATISM, _n._ State of unusually increased or intensified
coloration.
HYPER´TROPHY, _n._ Inordinate enlargement of a part or organ, due to
excessive nutrition. The opposite of _atrophy_, or the wasting away of
an organ through deficient nutrition.
HYPO- (_in composition_). Same as _sub-_ (which see).
HYPOCHON´DRIUM, _n._ The flank. (Oftener used in the plural,
_hypochondria_, flanks.) (67.)