Detached Hydrophyllia 
of Athorybia rosacea, a si- 
phonophorous hydrozoan. 
Hydrophyllaceae 
A natural order of plants, the waterleaf family, 
consisting mostly of herbs, or rarely shrubs, 
with a watery insipid juice, alternate or rarely 
opposite leaves, no stipules, mostly scorpioid in- 
florescence, regular pentamerous and pentan- 
drous flowers, with the stamens borne on the 
lower part of the corolla and alternate with its 
lobes, a dimerous ovary, and 2 distinct styles. 
There are 16 genera and about 150 species, most 
of which are North American. Also called Hy- 
droleacece. 
Hydrophylleae (hi-dro-fil'e-e), n. pi. [NL., < 
Hydrophyllum + -ea;.~\ A tribe of plants of the 
natural order Syd/ropkyttavece, differing from the 
other tribes in having the corolla-lobes often 
contorted. 
hydrophyllia, . Plural of hydrophyllium. 
hydrophylliaceous (hi-dro-fil-i-a'shius), a. [< 
Hydrophyllium + -aceous.\ Having the char- 
acters of a hydrophyllium. 
hydrophyllium (hi-dro-fil'i-um), .; pi. hydro- 
phyllia (-a). [NL., < Gr. 
Mup (Mp-), water, + </>>').- 
"t.ov = L. folium, leaf.] 
The peculiar protective 
envelop or hydrotheca of 
the hydranths of some 
oceanic hydrozoans, as the 
Siphonophora, of laminar 
or foliaceous character. 
Also called bract. 
hydrophylls (hi'dro-filz), n. pi. [(Lindley, 
1846) < Hydrophyllum.] Lindley's name for 
the waterleaf family, the Hydrophyllacea. 
Hydrophyllum (hi-dro-fil'um), n. [NL. 
(Tournefort) (so called because of a cavity in 
each leaf which 
holds a small 
quantity of wa- 
ter), < Gr. Map 
(Mp-), water, + 
<j>vMav, a leaf.] 
A genus of 
dicotyledonous 
gamopetalous 
plants, the type 
of the natural 
order Hydro- 
phyllacea; and 
tribe Hydro- 
phylleie. They 
are characterized 
by having thecalyx 
nearly open, with 
or without a small 
appendage at each 
sinus; the corolla 
campanulate, the 
tube within bear- 
ing a linear longi- 
tudinal appendage 
opposite each 
lobe, with in- 
folded edges form- 
ing a nectariferous 
groove ; filaments 
and style long-ex- 
serted ; ample petioled leaves ; and the flowers white or 
pale-blue, and cymose. Only 6 or 8 species are known, all 
natives of North America. They are all called waterleaf. 
hydrophysocele (hl-dro-fi'so-sel), . [< Gr. 
Mup (vdp-), water, + Qiiaa, a bellows, a bubble, + 
IOI'MI, a tumor.] In pathol., a hernia containing 
both serous fluids and gas. 
Hydrophyta (hl-drof 'i-ta), n. pi. [NL. (Lyng- 
bye, 1819), < Gr. Mup (Mp-), water, + <t>vr6v, a 
'plant.] 1 . A name proposed as a substitute for 
the word Algw. The word has never been much used, 
and is, moreover, objectionable, since not all submerged 
plants are algse, and it is not applicable to aerial forms. 
2. [/. c.] Plural of hydrophyton. 
hydrophyte (hi'dro-fit), . [< Gr. Mup (Mp-), 
water, + <j>vr6v, a plant. ] A plant which grows 
in water ; an aquatic plant. 
hydrophytography (hi' / dro-fi-tog'ra-fi), n. [As 
hydrophyte + Gr. -ypaQia, < ypcujie/v, write.] The 
description of water-plants. [Bare.] 
hydrophytology (hi*dro-fl-tol'o-ji), n. [As hy- 
drophyte + Gr. -).oyia,<. teyem, speak : see -ology.] 
That branch of botany which relates to aquatic 
plants. 
hydrophyton (hi-drof'i-ton), n. ; pi. hydrophyta 
(-ta). [NL., < Gr. Mup (vdp-), water, + $vr6v, a 
plant.] In the hydroid acalephs, the common 
support by which the several zoSids of a colony 
are connected one with another. The base or 
proximal end of the hydrophyton is the hydrorhiza; the 
Intermediate part between the hydrorhiza and the hydranth 
is the hifdrocaulus. 
hydrophytous (hl-drof 'i-tus), a. [As hydrophy- 
ton -t- -on*.] Having the character of a hydro- 
phytou. 
hydrppically (hi-drop'i 
dropical or dropsical ma 
2939 
hydropic (hl-drop'ik), a. and H. [< ME. ydropik, 
< OF. hydropique, idropique, F. hydropique = Sp. 
hidropico = Pg. hydropico = It. idropico, < L. hy- 
tlropicux, < Gr. vtipumKOf, dropsical, < Mpoty, 
dropsy: see hydropsy, dropsy.] I. a. Contain- 
ing or produced by water ; dropsical. 
Drye folk & ydropiJce, & dede at the laste ; 
Alle called on that cortayse t claymed his grace. 
Alliterative Poems (ed. Morris), ii. 1006. 
Hydropick humors not discernable at first from a fair 
and juicy fleshinesse of body. 
Milioii, On Def. of Humb. Kemonst. 
Every lust is a kind of hydropic distemper, and the more 
we drink the more we shall thirst Tillotson. 
II. n. 1. A medicine that relieves or cures 
dropsy. 2. A dropsical person, 
hydropical (hi-drop'i-kal), a. [< hydropic + 
-al.] Same as hydropic" 
Waterish or hydropical tumours are the effects of an 
extravasated serum. Wiseman, Surgery, i. 23. 
-kal-i), adv. In a hy- 
manner. 
It may I confess by siccity and astriction afford a con- 
firmation unto parts relaxed, and such as be hydropically 
disposed. Sir T. Browne, Vnlg. Err., ii. 3. 
hydropisyt, n. An earlier form of hydropsy. 
hydroplanula (hi-dro-plan'u-la), n.; pi. hydro- 
planma; (-le). [NL., < Hydra, a genus of hy- 
drozoans, + planula, a stage of the embryo.] 
The transitional stage of the embryo of a hy- 
drozoan intermediate between the planula and 
the tentaculated actinula. 
hydropneumatic (hl'dro-nu-mat'ik), a. [< Gr. 
vdup (Mp-), water, + irvev/uaTiKof, of or caused 
by wind or air : see pneumatic.] Of or pertain- 
ing to, or produced by, the action of water and 
air; involving the combined action of water 
and air or gas Hydropneumatic accumulator. 
See accumulator. 
hydropneumonia (hl"dr6-nu-m6'ni-a), n. [NL., 
< Gr. Mup (Mp-), water, 4- NL. pneumonia, q. v.] 
In pathol., dropsy or edema of the lungs. 
hydr opneumopericar dium ( hi-dro-nu-mo-per- 
i-kar'di-um), n. [NL.,< Gr. Mup (Mp-), water, + 
irvevfia, breath, wind (cf. nvevfiuv, lung), + irtpt- 
Kapdtov, pericardium.] In pathol., the presence 
of serous fluid and air in the pericardial cavity. 
hydropneumothorax (hi-dro-nu-mo-tho'raks), 
n. [NL., < Gr. Mup (vdp-), water, -f- NL. pneu- 
mothorax, q. v.] In. pathol., the presence of air 
and serous fluid in a pleural cavity. 
hydropolyp (hl'dro-pol-ip), . [< Gr. Mup 
(Mp-), water, + iro/lwrovf, polyp : see polyp.] A 
hydroid polyp; a hydrozoan, as distinguished 
from a coral polyp or actinozoan. 
Hydropolypinse fhi-dro-pol-i-pi'ne), n. pi. 
[NL., < Gr. vdup (Mp-), water, + iroZvirarvf, polyp, 
+ -inw.] A suborder of Hydromedusce, mul- 
tiplying by budding and by sexual products 
which do not appear in the shape of medusas. 
The budding polyps may be disintegrated from the parent 
Waterleaf (HydrafhyUum Yirginicum). 
a, flower ; b, fruit. 
and so all remain solitary, or they may remain ati 
and so form a colony. In both cases sexual multiplication 
alternates with the process of budding. The sexual pro- 
ducts are matured in the wall of the body-cavity, which 
may form hollow tentacular processes in which the ova 
and spermatozoa are found. 
hydropropulsion (hi'dro-pro-pul'shon), n. [< 
Gr. Mup (Mp-), water, * E. 'propulsion.] Pro- 
pulsion of vessels by a hydromotor. 
hydrqps (hi'drops), n. [NL., < Gr. Mputy, drop- 
sy^ Mup (Mp-), water: see hydro-. Cf. hydrop- 
sy.] Same as hydropsy.-SyOiofB of the anterior 
chamber. Same as buphthalmos. 
hydropsy (hi'drop-si), n. [Earlier hydropisy, < 
F. hydropisie = Sp. hidropesta = Pg. hydropesia, 
hydropisia = It. idropisia, < L. hydropisis, for 
*hydropiasis, < Gr. Mpuiriaats, dropsy, < vdpumav, 
have the dropsy, < Mpuiji, dropsy : see hydrops.] 
Dropsy : the original form, of which dropsy is a 
contraction. 
Soft-swoln and pale, here lay the Hydropsy: 
Unwieldy man ; with belly monstrous round. 
Thomson, Castle of Indolence, i. "5. 
Hydropsyche (hi-drop-si'ke), . [NL., < Gr. 
Mup (vdp-), water, + Tlnixfi, a butterfly: see Psy- 
che.] The typical genus of Hy dropsy chida;. 
Hydropsychidae (hi-drop-sik'i-de), n. pi. [NL. 
(Curtis, 1835), < Hydropsyche + -idee.] A fam- 
ily of trichopterous insects, or caddis-flies, typi- 
fied by the genus Hydropsyche, having the third 
joint of the maxillary palpi elongate and fili- 
form, the antenna? setaceous, and the feet 
spurred . The larva? are aquatic and predaceous, 
and inhabit stationary cases. 
Hydropterideae(hi-drop-te-rid / e-e), n.pl. [NL., 
< Gr. Mup(Mp-), water, -f- itTepic oTTTTsptc (-id-), a 
Hydrosaurus 
the families Marsiliacece and Salviniacece, which 
are characterized by possessing both macro- 
spores and microspores. Also called Hhizocar- 
jiin . 
hydroptic (lii-drpp'tik), a. [Irreg. < hydropsy 
+ -ic.] Pertaining to or affected with hydrop- 
sy; dropsical; hence, thirsty. [Rare.] 
This I made account that I begun early, when I under- 
stood the study of our laws ; but was diverted by the worst 
voluptuousness, which is an hydroptic immoderate desire 
of human learning and languages. Donne, Letters, xx. 
He, Boul-hydroptic with a sacred t hii st . 
Sucked at the flagon. 
Browning, Grammarian's Funeral. 
Hydroptila (hi-drop'ti-la), . [NL. (Dalman, 
1819), < Gr. Mup (mp-), water, + KT'I)J>V, down, 
feathers.] The typical genus of caddis-flies of 
the family Hydroptilidai, having ocelli, scarcely 
acuminate wings, and the head with elevated 
lobes posteriorly. 
Hydroptilidae (M-drop-til'i-de), n. pi. [NL. 
(Stephens, 1836), < Hydroptila + -id7] A fam- 
ily of trichopterous insects, or caddis-flies, typi- 
fied by the genus Hydroptila, containing very 
minute forms which resemble microlepidopter- 
OUS insects. They are very hairy, with simple palpi 
and short antennee. The larvee are found in both running 
and standing water, and build free membranous cases, to 
which a few grains of sand are sometimes added. 
hydropult (hi'dro-pult), n. [< Gr. Mup (Mp-), wa- 
ter, + E. (cata)pult.] A portable force-pump; 
a garden-pump. Also hydrapult. 
hydropyretic (hi'dro-pl-ret'ik), a. [< Gr. Map 
(Mp-), water, + irvperSf, fever: see jiyretic.] In 
pathol., of or pertaining to fever that is accom- 
panied by sweating. 
hydroquinone (hl-dro-kwi'non), . [< hydro- 
(gen) + quinone.] A divalent phenol (CfiH 4 
(OH) 2 ) prepared by the oxidation of aniline 
and treatment of the quinol formed with sul- 
phurous acid . It is a crystalline substance with a sweet 
taste, and is readily soluble in hot water. It is much used in 
place of pyrogallic acid as an agent for the development 
of photographic plates. Also hydrochinon and ericinone, 
and more properly hydroquinol. 
Hydroquinone belongs to a class of organic bodies that 
the chemist calls diphenols. Sci. Amer., N. S., LVII. 376. 
hydrorachis, hydrorrhachis (hi-dror'a-kis), 
n. [NL., < Gr. Mup (Mp-), water, + payis, spine.] 
In pathol., serous effusion in the spinal canal. 
When this is in cavities within the spinal cord it is called 
hydrorachis interna, or Jiydromyelia; when between the 
cord and the walls of the canal, hydrorachis externa. Hy- 
drorachis alone usually denotes hydrorachis externa. 
hydrorhiza (hl-dro-ri'zfl), n.; pi. hydrorhiza! 
(-ze). [NL., < Gr. Mop (Mp-), water, + pit^a, 
root.] The corm or rootstock of a fixed hydro- 
zoan ; the common base of a colony of hydroids, 
by which it is attached to some support. 
The base begins to divide up and send out processes. 
These latter grow and ramify in a manner strikingly like 
that of the roots of a tree, and produce what is technically 
known as the hydrorhiza. Stand. Nat. Hist., I. 78. 
hydrorhizal (hl-dro-ri'zal), a. [< hydrorhiza + 
-al.] Having the character of a hydrorhiza; 
pertaining to a hydrorhiza. 
hydrorhodonite (hl"dro-r6'do-nit), . [< Gr. 
Mup (Mp-), water, + i>66ov, rose, + -i<e 2 .] A hy- 
drated manganese silicate found at Langban in 
Sweden. 
hydrorrhea, hydrorrhoea (hl-dro-re'a), . 
[NL. hydrorrho3a,<.Gi. Mptppoea, lit. a flowing of 
water, < Mup (Mp-), water, + poia, a flowing, < 
ptiv, flow.] In pathol., a copious watery dis- 
charge. 
hydrosalpinx (hi-dro-sal'pingks), n. [< Gr.. 
Mup (Mp-), water, + o-a/tTRyf, a trumpet.] In 
pathol., the accumulation of serous liquid in a 
Fallopian tube. 
hydrosarcocele (hi-dro-sar'ko-sel), n. [< Gr. 
Mup (Mp-), water, + sarcocele, q. v.] In pathol., 
sarcocele attended with dropsy of the tunica 
vaginalis. 
Hydrosaurus (hi-dro-sa'rus), n. [NL., < Gr. 
(Mp-), water, + aavpoc, lizard.] A notable 
fern, + -em.] A class or group of cryptogamous 
plants, the heterosporous Filicinece, comprising 
Water-monitor {Hyilrosaurus salvator}. 
