their conjoint operation in man; the doctrine of the relation of function or dependence between body and
(Psy"cho*pomp) n. [Gr. psychh` the soul + to send: cf. F. psychopompe.] (Myth.) A
leader or guide of souls . J. Fiske.
(Psy*cho"sis) n. [NL. See Psycho- .]
1. Any vital action or activity. Mivart.
2. (Med.) A disease of the mind; especially, a functional mental disorder, that is, one unattended with
evident organic changes.
(Psy`cho*zo"ic) a. [Psycho- + Gr. life.] (Geol.)Designating, or applied to the Era of man; as,
the psychozoic era.
(Psy*chrom"e*ter) n. [Gr. psychro`s cold + -meter: cf. F. psychromètre.] An instrument
for measuring the tension of the aqueous vapor in the atmosphere, being essentially a wet and dry bulb
(Psy`chro*met"ric*al) a. Of or pertaining to the psychrometer or psychrometry.
(Psy*chrom"e*try) n. Hygrometry.
(||Psyl"la) n.; pl. Psyllæ [NL., from Gr. a flea.] (Zoöl.) Any leaping plant louse of the genus Psylla,
or family Psyllidæ.
(Ptar"mi*gan) n. [Gael. tarmachan; cf. Ir. tarmochan, tarmonach.] (Zoöl.) Any grouse of
the genus Lagopus, of which numerous species are known. The feet are completely feathered. Most of
the species are brown in summer, but turn white, or nearly white, in winter.
They chiefly inhabit the northern countries and high mountains of Europe, Asia, and America. The common
European species is Lagopus mutus. The Scotch grouse, red grouse, or moor fowl is reddish brown,
and does not turn white in winter. The white, or willow, ptarmigan (L. albus) is found in both Europe and
(||Pte`no*glos"sa) n. pl. [NL., fr. Gr. feathered + tongue.] (Zoöl.) A division of gastropod
mollusks having the teeth of the radula arranged in long transverse rows, somewhat like the barbs of a
(Pte`no*glos"sate) a. (Zoöl.) Of or pertaining to the Ptenoglossa.
(Pte*ran"o*don) n. [Gr. wing + priv. + a tooth.] (Paleon.) A genus of American Cretaceous
pterodactyls destitute of teeth. Several species are known, some of which had an expanse of wings of
twenty feet or more.
(||Pte*ran`o*don"ti*a) n. pl. [NL.] (Paleon.) A group of pterodactyls destitute of teeth, as
in the genus Pteranodon.
(||Pte*rich"thys) n. [NL., fr. Gr. wing + fish.] (Paleon.) A genus of Devonian fossil fishes
with winglike appendages. The head and most of the body were covered with large bony plates. See
(Pter`i*dol"o*gist) n. One who is versed in pteridology.
(Pter`i*dol"o*gy) n. [Gr. a fern + -logy.] That department of botany which treats of ferns.