opercular 
these are unlte<l into u more <>i less movable 1M \vtii<'h 
rovrrH tilt' gills. -^" I" 1 '! 1 "1C 'IcVfluJM'il ill the t\|. ir.it 
tt'leosts, but our nr more an: wanting in sonic llshea. See 
cut under ('(<"/. Opercular fissure, the pumatic fls- 
stire of a monk. "v's bruin. Seej/owwdV. Opercular flap, 
u backward prolOQgAtloa of the opercle or nmny ii>h. -, aa 
the - n 1 1 iMn-s, in some of which It attains a gi eat siz.-. - . . 
Lepmni*. opercular gill scefftKi. 
Operculata (o-per-ku-la'tii), n. ///. [NL., neut. 
pl. of Li.opfiriilnliix, covered with a lid: soeoper- 
i-M/ri/f-'.] Bhelli which are operculftte. The term 
is sperillcully applied to those pulmonate gastropods which 
have an opercufum developed from the upper back por- 
tion of the foot, closing the shell when the iinlmul Is with- 
drawn into it. The chief family Is CycloKtumidce. See cuts 
under AmpuUariidas and Mtuinnfidn'. 
operculate (o-p6r'ku-lii,t),n. [= !'. //(///<' = 
Sp. Pg. opercitlado, < L. optrculatus, pp. of 
operciilun: furnish with a Hit or cover, s opcr- 
culum, a lid: Hee<>/KTe<iiiM.] Having an oper- 
oulum; operculigerous; specifically, of or per- 
taining to tlic Oparoulaia, 
operculated (o-per'ku-la-ted), . [< operculate 
+ -orf 2 .] Same as operculate. 
opercule (o-per'kul), n. Same as /)<- 
MM. 
operculiferous (o-per-ku-lif'e-rus). . [< L. 
operculum, a lid, + ferre = E. 6crl.J Opercu- 
ligo rous. 
operculiform (o-per'ku-li-fdrm), . [< L. 
operritliun, a lid, 4- forma, form.] Having the 
form of a lid or cover ; resembling an opereu- 
lum. 
operculigenous (o-p6r-ku-lij'e-nus), a. [< L. 
operctiluiii, a lid, + gigitcre, gcttere, proauce: 
see -f]enous.~\ Producing an operculum: specif- 
ically, noting the inetapodium or posterior part 
of the foot of gastropods. 
operculigerous (o-per-ku-lij'e-rus), a. [< L. 
operi'ulum, a lid, + gerere, carry.] Having an 
operculum; operculate. 
Operculum (o-per'ku-lum), n. ; pi. operciila 
(-la). [= F.'opercule = Sp. operciilo = Pg. It. 
operciilo, < L. operculum, a lid, cover, 
< opcrire, cover, cover over, shut, 
close, conceal: see overt.] A lid or 
cover; in not. hist., a part, organ, or 
structure which forms a lid, nap, or 
cover. Specifically -(<z) In (XX. : (IJInJftMei, 
the lid of the capsule : it covers the peristome, operculum 
and usually fulls off when the spores are ready of Moss. 
for dispersion. (2) In phanerogams, some- 
times, the lid or top of certain circumscissile capsules 
(pyxlsX as in Portulaca, Planlago, etc. (3) The conical 
limb of the calyx of Eucalyptus. See cuts under Ascidium 
and inogg. (6) In zool.: (1) In conchology, a horny or shelly 
plate secreted by 
the operculige- 
nous organ of 
gastropods and 
some other mol- 
lusks, serving to 
close the aper- 
ture of the shell 
when the ani- 
mal is retracted. 
See cuts under 
Ampullariidce 
and Macluriti- 
d<K. (2) In cirri- 
peds as llalani- 
ner side. *. concentric operculum Jf/* th .n*wKl.i 
} ; c. imbricated or lamellar (Pur- <*. t he movable 
. 
, rf. nmltispiral (TrecAuj]; r. unguicu- 
late or claw-shaped (f-'Hsus) ;/, subspiral (Mr- 
'I :r, articulated (Nfrilal : *, pa 
cispiral 
Capsule and Operculum of Shell. 
a. Turbo olearitts g. operculuin, outside ; A, 
operculum. Inner side. *. concentric operculum 
{Amfullar,, } ; c. imbricated or lamellar (Pur- 
Part of the rig- 
id shell, which 
forma a fl ap cov . 
erlng the en- 
trance to the mantle-cavity. (3) In Crustacea, the eighth 
pair of appendages of a king-crab, united together into a 
single broad plate, on the dorsal surface of which the 
genital organs open, and which forms a flap covering the 
succeeding appendages of this division of the body. See 
l.iiHiilnx. (4) In Polyzoa, as Chiloxtamata, that part of 
the ectocyst of the cell of the polypid which forms a 
movable lid shutting down upon the zooid when the latter 
is withdrawn into its cell. (6) In ichthyology, the hind- 
most and uppermost bone of the opercular apparatus or 
gill-cover. See opercular apparatus, and also cuts under 
palatitqiiadrate, SpattUaria, and telewt. (6) In ornithology: 
(a) The nasal scale; the small horny or membranous lid 
or flap which covers or closes the external nostrils of sun- 
dry birds. (8) The ear-conch or feathered flap which closes 
the ear of an owl. (7) In mammalogy, parts of the ear of 
an aquatic mammal, as a shrew or vole, so arranged as to 
act like a valve to prevent the entrance of water. (8) In en- 
tomology. one of two small pieces on the sides of the ineta- 
thorax, covering the spiracles or breathing-orifices. Also 
called teyula and covering-Kale. (9) In Araehniiia, one of 
the small scales covering the stigmata or brcathing-ori 
tlces of a spider. They are distinguished as the branchial 
nla, covering the openings of the branchiie, and the 
traclif.al vperciUa, nearer the base of the abdomen or 
sometimes at the end, covering the iinth-rs of tli" ti 
The latter ure often absent. (10) In Infusoria, the lid of 
the lorica, as of the VortictUulas. (c) In mint, of the brain, 
the principal covering of the insnla or island of Beil. over- 
lapping the pryri operti from above, and formed mainly by 
the precentral ami postccntral gyri united below the end 
of the Ilolandic or central flssure. See cuts under cerebral 
and <ryrus. Muricold operculum. See mwruxM. 
opere in medio (op'e-re in me'di-6). [L.: <I\M n: 
abl.of opus, work; in, in: media. abl. of median, 
middle.] In the midst of (one's) work. 
4123 
Operetta top-e-ret'ii), H. [= F. nprrettr, < It. 
o/ii-rettii, dim. of opent, nil opera,: sec i/p/vvi.J 
A short opera, generally of a light ; character 
and so belonging to the class of comic opera or 
opera bouffe. 
operose (p';;-r6s), (i. [= Sp. Pg. It. operano, < 
li.aptnisitii. giving much labor, laborious, indus- 
trious, also costing much labor, troublesome, 
toilsome, < oju-rn. .</rv (/<cr-),\vork: see //</, 
opux.~\ Laborious; attended with labor; tvilions. 
Aa to the Jewish religion, it was made up of a busy and 
operose law of carnal ordinances, which had but a very dim 
pronpect beyond the enjoyment of plenty and uttluence. 
Keelyii, True Religion, II. 17'.). 
The task, . . . however (rpertme it may seem, is within 
the power of any one learned lawyer. 
Story, Misc. Writing!, p. 898. 
operosely (op'e-ros-li), rfc. In an operose 
manner. 
operoseness (op'e-ros-nes), . The state of be- 
ing operose or laborious. 
operosity (op-e-ros'i-ti), H. [= It. aperosita; 
as operose + -%.] Ijaboriousness. 
There is a kind of operoniy in sin, In regard whereof 
sinners are styled the workers of iniquity. 
Bp. Hall, Select Thoughts, | 66. 
OperoUSt (op'e-rus), a. Operose. Holder. 
operouslyt (o"p'e-rus-li), adv. In an operous 
manner. 
opertaneous (op-er-ta'ne-us), a. [< L. oper fa- 
ttens, concealed, hidden, < opertun, pp. of ope- 
rire, cover, conceal : see operculitm. j Secret ; 
private. [Rare.] 
opetidet (op'tid), n. See open-tide. 1. 
Ophiastra (of-i-as'tra), n. pi. [NL., < Gr. 6^<f, 
a serpent, T aariip, a star.] In Lankester's clas- 
sification, one of two orders of OpJiiuroidea, con- 
trasted with Phytastra. 
Ophibolus (o-fib'6-lus), H. [NL., irreg. (cf. 
ixptofJA&of, serpent-slaying) < Gr. o^if, a serpent, 
T pd)J^tv, throw.] A large and beautiful genus 
of harmless serpents of the family Colubrida'. 
There are numerous species in the United States, called 
kiny -miilcr* and by other names, such as 0. gttulut, O. myi, 
and 0. eximiwt. They are of various shades of black, 
brown, or red. blotched with lighter colors, the blotches 
generally black-bordered. 
ophicalcite (of-i-kal'sit), n. [< Or. tyif, a ser- 
pent, + E. calcite. Cf. serpentine, n.] Same as 
rcrd-antiquc. lirongniart. 
Ophichthyidae (of-i'k-thi'i-de), n. pi. [NL., < 
Ophichthys + -ifte.] A family of apodal fishes, 
typified by the genus Opliichtliys, containing 
eels whose nostrils perforate the edge or inner 
side of the lip. The form is often slenderer than in a 
common eel : the posterior nostrils are labial that is, are 
on the margin or even the inside of the upper lip ; and the 
tongue is attached to the floor of the mouth. In some spe- 
cies the tail is conical or Unless ; in others it is surround- 
ed by a lin. as usual in eels, whence the two subfamilies 
OphichthyincK and Myrince. Several genera are found in 
the waters of the southern and Pacific coasts of the United 
States. 
Ophichthyinae (o-fik-thi-i'ne), . pi. [NL., < 
Oph ich thys + -in<B.] A subfamily of Ophich thy- 
ida; having the tail finless: contrasted with 
Myrinif. 
Opnichthys (6-fik'this), . [NL., < Gr. 6<t>if, a 
serpent, + i;r&'<;, a fish.] The typical genus of 
Ophic)itlii/idir, of snake-like form (whence the 
name), and haying no pectoral fins. Swainson. 
ophicleide (of 'i-klid), n. [< Gr. tyic,, a serpent, 
-I- it).tif (K/IFJ-), a key: see clavig.] A metal 
musical wind-instrument, invented about 1790, 
having a large tube of conical bore, 
bent double, with a cupped mouth- 
piece. It is essentially a development of the 
old wooden serpent, and has sometimes been 
made partly of wood ; It is the bass represen- 
tative of the keyed-bugle family. The tones 
produced are the harmonics of the tube, as in 
the horn; but the fundamental tone may be 
altered by means of keys which control vents 
in the side of the tube. Eleven such keys are 
employed, so that the entire compass is over 
three octaves, beginning (in the usual bass 
variety) on the third B below the middle C, 
with all the semitones all obtainable with 
exceptional accuracy of intonation. Its re- 
sources are therefore considerable, and as its ophE< 
tone is highly resonant and pungent it is an 
important orchestral instrument. The alto ophicleide is 
pitched a fifth higher than that described above, while 
lower varieties also occur. 
ophicleidist (of'i-kli-dist), . [< opnideide + 
-is?.] A performer on the ophicleide. 
Ophideres (o-fid'e-rez), n. [NL. (Boisduval, 
ls:W), prop. "Ophiodcres (cf. Gr. tyMeipof, ser- 
pent-necked), C60/f, a serpent, + tfpr/, Attic 6rt- 
!,: neck, throat.] The typical genus of Opliide- 
ridir, having the palpi spatulate or clavate, and 
the hind wings lutecms. It is very widely distrib- 
uted in both hemispheres : the species are large and often 
beautifully colored. 0. fullonica of South Africa damages 
PI 
-MX 
Base of Ordinary Ophidian 
Skull ( python). 
no, basioccipital ; BS, basi- 
sphenoid ; MX, maxillary ; 
Pmx, premaxillary ; /'/. pala- 
tine ; ft, jtterygoi<l ; ON, quad- 
rate; Sq, squaiiiosal; lr, trans- 
verse bone: l-'o. vomer. (The 
tcetli are aglyphodont.) 
Ophidium 
oranges by piriring tlmn with its haii-t< Hum and suck* 
ing the juice. 
Ophideridae (oi'-i-.i.T'i-de), . pl. [NL. (Gue- 
nee, 1X5:.'), < OphMerm + -ida:'] A family <>( ni - 
t uiil moths of large size and striking coloration, 
represented by Ojihideres and five other genera 
in nearly all fauna except the European. 
Ophidia (y-liil'i-ii),H.;;/. [N'L.,pl. of "niih id inn, 
\Gr. ixtiiihov, dim. in form, but not in sense, of 
6^/f, a serpent; or improp. for 'Ophioiilca, !r. 
ty/f, a serpent, + / iriof, fonn.] An order of t lie 
class Brptilia, without developed limbs, with 
mobile quadrate bone and separate mandiim- 
lar raini ; the snakes or serpents. The name was 
introduced to replace Scrprntei of I.inmeus, and at first 
Included not only serpents in a proper sense, but certain 
footless lizards, and even the amphibians of the family 
Cieciliidif. In Ophidia proper there is never any trace of 
fore limbs, and at most very 
rudimentary hind limbs, rep- 
resented externally by mere 
anal spurs or processes of the 
Integument There is no ster- 
num. The ribs are very nu- 
merous, and are so arranged 
as to become indirect organs 
of locomotion by their action 
upon the skin and so on the 
scales of the belly. The ver- 
tebra; are precocious, very nu- 
merous, not united in any 
sacrum, and bearing no chev- 
ron-bones. The skull has no 
qnadratojugal arch nor pari- 
etal foramen ; the lower jaw 
is articulated with a movable 
quadrate bone, and its ram! 
are connected only by fibrous 
tissue. The bones of both 
jaws are generally freely mov- 
able, so that the mouth is 
enormously distensible. The 
tongue is slender, forked, and 
protrusile, subserving atactile 
office. Teeth are present in 
one or both jaws, usually in 
both ; they are numerous and 
sharp, and in venomous Ophi- 
dia some of the upper ones, 
usually a single pair, are en- 
larged, hooked, grooved, or ap- 
parently perforate, and thus converted Into poison-fangs. 
The eyes nave no movable lids, the cuticle extending direct- 
ly over the eyeball. The cuticle is scaly, forming many very 
regularly arranged rows of scales on the upper parts, and 
usually larger modified scutes on the under side, called 
gatrtrogteyes and urogtegen, serving to some extent for loco- 
motion. There is a pair of extracloacal penes In the male ; 
the female is oviparous or ovoviviparous. Ophidia are 
variously subdivided by bmncril and fiibron into Ovo- 
terodonta, Aglyphodonta, Proteroglypha, and Soleiwglypha , 
an arrangement substantially now current, though with 
some modifications. Cope's latest arrangement is Epano- 
donta, Catodonta, Tartricina, which are opoterodont, An- 
nea, which are aglyphodont, Proteroglypha, and Solenogly- 
pha. There are 20 families and about SCO genera, of 
which more than 200 belong to the family Cijubrida alone. 
See also cut under Python. 
ophidian (9-fid'i-an), a. and . [< Ophidia + 
-an.] I. a. Having tne nature or characters of 
a snake or serpent; belonging or relating to 
ophidians; of or pertaining to the Ophidia. 
Also ophidians. 
H. n. A member of the Ophidia, as a snake 
or serpent. 
ophidiana (o-fid-i-a'nS), n.pl. [< Gr. fyUltov, 
dim. of o^(f, a serpent, snake (cf. ophidian), 
+ -flH 2 .] Anecdotes or stories of snakes. 
ophidiarium (o-fid-i-a'ri-um), n. ; pl. ophidiari- 
ii in* or ophidiaria (-umz, -ft). [NL., (Ophidia 
+ -arium.] A place where serpents are kept in 
confinement, for exhibition or other purposes; 
a snake-house. 
Ophidiidae ( of-i-dl'Me), n. pl. [NL. , < Ojihidi- 
um + -ido-.] A family of ophidioid fishes, typi- 
fied by the genus Ophidium, having the ventral 
fins advanced to the lower jaw, or situated un- 
der the chin, so that they resemble barbels. 
(1) In Bonaparte's early systems* the Ophidiida embraced 
two subfamilies, Ophidiitii and Ammodytini. (2) In Gun- 
ther's system they are a family of gadoid fishes corre- 
sponding to the modern Ophidiaidea. (3) In Gill's system 
the family is restricted to those Ophidioidea which have 
the ventral fins under the chin, bifid barbels, and the anus 
in the anterior half of the length of the fish, represented 
by four genera. See cut at Ophidium. 
ophidioid (o-fid'i-oid), . and n. [As Opliidia 
+ -oid.1 I. a. Belonging to the family Ophidi- 
idtf, or having their characters. 
II. n. A fish of the family Ophidiida'. 
Ophidioidea (o-fid-i-oi'de-ii\ . pl. [NL., < 
Opliiiliinii + -oidea.] A siiperfamily of teleo- 
cephalous fishes, embracing the families liro- 
tulida', Ophidiidte, Fierusferida', and perhaps 
others less known than these. 
ophidious io-fid'i-us), a. [< Ophidia + -oua.] 
Sumo as njiiiiilian. 
Ophidium (9-fid'i-um), . [XL.. < Gr. IxfiSiav, 
dim. of 6o<r, a serpent. ( '{. o^liiilio.} 1. A ge- 
nus of fishes of the family Ophidiida: instituted 
