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Full text of "A dictionary of scientific terms : pronunciation, derivation, and definition of terms in biology, botany, zoology, anatomy, cytology, embryology, physiology"

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(2ik O f Stephen Rook 



A Dictionary of Scientific Terms 








W. D. HENDERSON, M.A., B.Sc.,PH.D.,F.R.S.E. 









Tins compilation was undertaken as it was thought desirable 
that there should be available to students and scientists, an 
up-to-date work somewhat on the lines of Stormonth's Manual 
of Scientific Terms (1879, republished 1903). It contains 
definitions of about ten thousand terms, including several 
hundred lately coined expressions, many of which have not 
hitherto appeared in a dictionary. The work is expected to 
supply a want felt by many students and other readers of 
the Biological Sciences, as the usual handy-sized dictionary 
contains comparatively few purely scientific terms. The sub- 
jects selected for treatment are Biology and its allies, Anatomy, 
Botany, Zoology, Embryology, Cytology, Physiology ; and 
some terms in Bacteriology and Palaeontology are included. 

In a first edition of a book of this kind, errors of omission are 
inevitable, as few people have convenient access to each text- 
book and treatise, even in one subject, as it makes its appearance 
Suggestions for additions will be welcomed and noted for future 
use, and should be accompanied by the name of the work in 
which the original definition is to be found ; derivation offers 
no difficulty as a rule, but pronunciation might be indicated by 
coiners of entirely new terms. 

In the etymological section, Greek words have been trans- 
literated, as science and medical students are seldom acquainted 
with that language, and on the advice of an authority on 
Greek, the transliteration of certain combinations of letters 
represents the sound rather than the exact letters of the 
original ; hence the frequent occurrence of such words as 
brangchia, hydor, etc. 

This work was begun by Mr J. H. Kenneth, who compiled 
most of the primary lists from which the whole has been 
elaborated. Mr Kenneth had completed upwards of three 



hundred terms when ill-health prevented his continuing the 
work, and it was handed over to the present authors. 

We have to acknowledge our indebtedness to Professor 
J. H. Ashworth of Edinburgh University, who has very kindly 
read over the manuscript and given us some suggestions for 

I. F. H. 



IT has seemed expedient in many cases to give alternatives, as different 
centres of learning have different types of pronunciation ; again, as it is 
usage which determines correct pronunciation, and the terms are not 
everyday words, it will be long before a term which lends itself equally 
well to two methods will be fixed down to one. 

As to many anatomical and other purely Latin terms, students will 
probably follow the type of pronunciation, English or Continental, 
learned at school ; in the latter case, the second alternative or some 
modification of it will be employed. Those who can readily pronounce 
ch as in loch, and who have so learned to pronounce the combination 
in Greek, will naturally introduce that sound into such words as 
branchial, brachycnemic ; although the k sound has been adopted in 
this as in other dictionaries, the other is not to be regarded as 

The sound-symbols have been made as simple as possible, only the 
broader differences of vowel-sounds having been included. A general 
indication of pronunciation, rather than a critically exact reproduction, 
is what is wanted for the average reader of scientific works. 

In the case of words which have not previously appeared in a 
dictionary, and whose pronunciation is not clearly indicated by 
etymological or other rules, it remains for the coiner to indicate his 




bot. . 
cyt. . 

Ar. . 
F. . 
Gk. . 
I eel. 
It. . 



as in not. 

































French u. 

















J opposite, 

applied to. 


\opposed to. 



pertaining to. 




for example. 



that is. 

v. . 
















L. . 




Late Latin. 






Middle English. 



Old French. 



Old High German. 










abactinal (abak'tinal, abakti'nal) a. 
[L. ab, from ; Gk. aktis, ray.] 
Appl. the area of an echinoderm 
body without tube-feet and in which 
the madreporite is usually included ; 
abambulacral ; antambulacral ; opp. 
actinal (zoo/.). 

abambulacral (ab'ambula'kral) a. [L. 
ab t from ; ambulare, to walk.] 
Appl. the area of an echinoderm 
body remote from that on which 
the tube-feet are found (zoo/.). 

abaxial (abak'slal) a. [L. ab, from ; 
axis, axle.] Pert, that surface of 
any structure which is remote or 
turned away from the axis (biol.). 

abaxile (abak'sil) a. [L. ab, from ; 
axis, axle.] Appl. an embryo in 
which the axis has not the same 
direction as the axis of the seed 

abbreviated (abre'vlated) a. [L. ad, 
to ; brevis, short.] Shortened ; 

abdomen (abdo'men, ab'domen) n. 
[L. abdomen, belly.] The belly ; in 
vertebrates, the part of the body 
containing the digestive organs ; in 
Arthropods and certain Polychaets, 
the posterior part of the body ; in 
Synascidians, part of the zooid 
below the thorax (zoo/., anat.). 

abdominal (abdom'Inal) a. [L. ab- 
domen, belly.] Pert, abdomen ; 
appl. structures, organs, or parts of 
organs situated in, on, or closely 
related to, the abdomen. 

abdominal pores, single or paired 
openings leading from the coelom 
to the exterior, in Cyclostomes and 
certain other fishes (zoo/.). 

abdominal reflex, contraction of ab- 
dominal wall muscles when the skin 
over the side of the abdomen is 
stimulated (phys.). 

abdominal regions, nine areas into 
which the abdomen is divided by 


two horizontal and two vertical 
imaginary lines, viz., hypochondriac 
(2), lumbar (2), inguinal (2), epigas- 
tric, umbilical, hyppgastric (anat.). 

abdominal ribs, ossifications occur- 
ring in the fibrous tissue between 
skin and muscles of certain reptiles 

abdominal ring, one of two openings 
in the fasciae of the abdominal 
muscles through which passes the 
spermatic cord in the male, and the 
round ligament in the female ; 
inguinal ring (anat.}. 

abducens (abdu'se'nz) n. [L. abducere, 
to lead away.] The sixth cranial 
nerve supplying the rectus externus 
which turns the eyeball outwards 

abduct (abdukt') v. [L. abducere, to 
lead away.] To draw away from 
the median axis (phys.}. 

abductor (abduk'tor) n. [L. abducere, 
to lead away.] A muscle that 
draws a limb or part outwards 

aberrant (abeYant) a. [L. aberare, to 
wander away.] Appl. species with 
characteristics not strictly in accord- 
ance with the type (bot., zoo/.). 

abiogenesis (abiqje'n'gsis) n. [Gk. a, 
not ; bios, life ; genesis, birth.] The 
production of living from non-living 
matter ; archegony ; autogony ; 
spontaneous generation (oio/.). 

abiology (ablol'oji) n. [Gk. a, not ; 
bios, life ; logos, discourse.] The 
study of non-living things ; anor- 

abomasum (aboma'zum, abom'azum) 
n. [L. ab, from ; omasum, paunch.] 
The read or fourth chamber of the 
stomach of ruminants (zoo/.). 

aboral (abo'ral) a. [L. ab, from ; os, 
oris, mouth.] Away from, or 
opposite to, the mouth. 

abort (abort') v. [L. abortus, prc- 



mature birth.] To be arrested in 
development ; to be born prema- 
turely (biol.) 

abortion (abor'shun) n. [L. abortus, 
premature birth.] Premature birth ; 
arrest of development of an organ 

abranchiate (abrang'kiat) a. [Gk. a, 
without ; brangchia, gills.] Without 
gills (zool.). 

abrupt (abrupt') a. [L. ab, from ; rum- 
pere, to break.] Appearing as if 
broken, or cut off, at the extremity. 
abruptly-acuminate, having a.broad 
extremity, as a leaf, from which a 
point arises (hot.). 

abruptly-pinnate, having the main 
axis of the epipodium not winged, 
but bearing a number of secondary 
axes which are winged (bot.). 
absciss (ab'sls) a. [L. abscindere, to 
cut off.] Appl. layer of cells just 
outside the cork-layer, to whose 
disorganization the fall of the leaf 
is due (bot). 

abscission (absish'un) n. [L. abscin- 
dere, to cut off.] The separation 
of parts (dot.). 

absorption (absorp'shun) n. [L. 
absorbere, to suck in.] The intus- 
susception of fluid by living cells 
or tissues ; the passage of nutritive 
material through living cells (biol., 

abstriction (abstrik'shun) n. [L. 
abstringere, to cut off.] The pro- 
cess of detaching spores (conidia) 
by the rounding off of the tips of 
the sporophores, as in mildews (bot.). 
abterininal (abter'mmal) a. [L. ab, 
from ; terminus, end.] Going from 
the end inwards (phys.). 
abysmal (abiz'mal) a. [Gk. abysses, 
bottomless.] Pert, depths of the 

abyssal (abis'al) a. [Gk. abysses, 
bottomless.] Pert, depths of the 
ocean ; appl. organisms or material 
usually found there (biol.). 
acanaceous (akana'shus) a. [Gk. 
akanos, thorn.] Bearing thorns or 
prickles, as leaves (bot.). 
acantha (akan'tha) n. [Gk. akantha, 
thorn.] Prickle (bot.) ; spinous 
process (zool). 

acanthaceous (akantha'shus) a. [Gk. 
akantha, thorn.] Bearing prickles. 

acanthin (akan'thin) n. [Gk. akantha, 
thorn.] A substance like chitin, 
strontium sulphate, forming the 
skeleton of the Radiolarians (phys.). 
acanthion (akan'thion) n. [Gk. akan- 
tha, thorn.] The most prominent 
point on the nasal spine (anat.). 
acanthocarpous (akan'thokar'pus) a. 
[Gk. akantha, thorn ; karpos, fruit.] 
Having the fruit covered with spines 
or prickles. 

acanthocephalous (akan'thokef'alus, 
-sef-) a. [Gk. akantha, thorn ; keph- 
ale, head.] With a hooked pro- 
boscis (zool.). 

acanthocladous (akan'thoklad'us) a. 
[Gk. akantha, thorn ; klados, branch.] 
Having spiny branches, 
acanthocyst (akan'thosist) n. [Gk. 
akantha, thorn ; kystis, bladder.] 
A sac containing lateral or reserve 
stylets in Nemerteans (zool.). 
acanthophore (akan'thofor) n. [Gk. 
akantha, thorn ; pherein, to bear.] 
A conical mass, the basis of the 
median stylet in Nemerteans (zool.). 
acanthosphenote (akan'thosfe'not) a. 
[Gk. akantha, thorn ; sphen, wedge.] 
Appl. an echinoid spine made up of 
solid wedges separated by porous 
tissue (zool.). 

acanthozooid (akan'thozo'oid) n. [Gk. 

akantha, thorn ; soon, animal ; eidos, 

form.] The tail part of the pro- 

scolex of Cestodes as distinguished 

from the body or cystozooid (zool.). 

acapnia (akap'nia) n. [Gk. akapnos, 

without smoke.] Diminution or 

want of carbon dioxide (phys.). 

acaulescent (akoles'ent) a. [Gk. a, 

without ; kaulos, stalk.] Having a 

shortened stem (bot.). 

accelerator (aksgl'erator) n. [L. ac- 

celerare, to hasten.] Appl. muscle 

or nerve which increases the rate 

of action (phys.). 

acceptor (aksep'tor) n. [L. accipere, 
to accept.] A body or substance 
which receives and unites with 
another substance or gas intro- 
duced (phys.). 

accessorius (akseso'rius) n. [L. ac- 
cedere, to go to.] A muscle aiding 
in the action of another ; the spinal 
accessory or eleventh cranial nerve 
accessory (akseVori) a. [L. accedere, 



to go to.] Additional or accom- 

accessory bud, an additional axillary 
bud (bot.). 

accessory chromosome, a chromo- 
some found in the sex-cells of various 
animals which by its peculiar be- 
haviour and the stage it appears at, 
is considered by some authorities 
to be the factor that determines sex. 

accessory nerve, the eleventh cranial 
nerve (anat.). 

accessory pancreatic duct, Santo- 
rini's duct (anat.). 

accommodation (akomoda'shun) n. 
[L. ad, to ; commodus, fitting.] The 
adjustment of the eye for receiving 
clear images of objects at different 
distances (phys.). 

accrescent (akres'ent) a. [L. accre- 
scere, to increase.] Appl. plants that 
continue to grow after flowering, or 
calyx continuing to grow after pol- 
lination (bot.). 

accretion (akre'shun) n. [L. accre- 
scere, to increase.] Growth by the 
external addition of new matter ; in 
protozoology, agglomeration (biol.). 

accumbent (akum'bent) a. [L. ac- 
cumbere, to lie on.] Appl. embryo 
having cotyledons with their edges 
turned towards the radicle, as in 
Cruciferae (bot.). 

acentrous (asen'trus) a. [L. a, with- 
out ; centrum, centre.] With no 
vertebral centra and with per- 
sistent notochord, as in certain 
fishes (zoo/.). 

acephalous (akef'alus, -sef-) a. [Gk. 
a, not ; kephale, head.] Having no 
structure comparable to the head, 
as in some molluscs (zool.). 

acerate (as'grat) a. [L. acer, sharp.] 
Needle-shaped ; pointed at one end, 
appl. monaxon or oxeote spicules 

acerose (as'eros) a. [L. acer, sharp.] 
Narrow and slender, with a sharp 
point ; as a pine-leaf (bot.). 

acervuline (aseYviilin) a. [L. acervus, 
heap.] Irregularly heaped to- 
gether, appl. foraminiferal tests 

acervulus (aser'vulus) n. [LL. dim. 
of acervus, heap.] A small heap 
or cluster ; especially of sporo- 
genous mycelium (bot.). 

acervulus cerebri, minute grains of 
a calcareous nature in the pineal 
gland, etc., of the brain (anat.). 

acetabulum (asgtab'ulum) n. [L. 
acetabulum, vinegar - cup.] The 
socket for the head of the femur, 

situated at the junction of the 
ilium, ischium, and pubis, all of 
which may or may not take part in 
its formation (anat.) ; in insects, 
the cavity of the thorax formed by 
the epimeron, sternum, and occa- 
sionally epigastrium, in which the 
legs are inserted ; the large pos- 
terior sucker in leeches ; one of 
the cotyledons of the ruminant 
placenta ; the sucker on the arms 
of a Cephalopod (sool.). 

acheilary (akl'lan) a. [Gk. a, with- 
out ; cheilos, lip.] Having the 
labellum undeveloped, as in some 
orchids (bot.). 

achene (aken') . [Gk. a, not ; 
chainein, to gape.] A monosper- 
mal seed-vessel which does not 
open or crack (bot.). 

Achillis tendo (Skills ten'do) n. 
[Achilles, hero of the Iliad, who 
had a vulnerable heel ; L. tendo, 
tendon.] The hamstring ; the 
united strong tendon of the gastro- 
cnemiusand solaeus muscles (anat.). 

achlamydeous (ak'lamid'eus) a. [Gk. 
a, without; chlamys, cloak.] Having 
neither calyx nor corolla (bot.). 

achromatin (akro'matin) n. [Gk. , 
without ; chroma, colour.] The 
non-staining ground substance and 
linin of the nucleus (cyt.). 

achromatinic (akro'matin'ik) a. [Gk. 
a, without ; chroma, colour.] Pert. 
achromatin, or resembling achro- 
matin in its properties (cyt.). 

acicular (aslk'ular) a. [L. acicula, 
small needle.] Like a needle in 
shape ; sharp-pointed (bot.). 

aciculum (aslk'ulum) n. [L. acicula, 
small needle.] One of the stiff 
basal setae in the parapodium of 
a worm (zool.). 

acinaciform (aslnas'iform) a. [L. 
acinaces, short sword ; forma, 
shape.] Shaped like a sabre or 
scimitar ; appl. leaf (bot.). 

acinarious (aslna'rlus) a. [L. acinus, 
berry.] Having globose vesicles, 
as some Algae (bot.). 



acinus (as'fnus) . [L. acinus, berry.] 
One of the pulpy drupes composing 
the fruit of bramble or raspberry 
(hot.} ; the sac-like termination of 
a branched gland (anat.). 

acoelomate (ase'lomat) a, [Gk. a, 
without ; koilos, hollow.] Appl. 
animals not having a true body 

acoelomatous,acoelous, acoelomate. 

acontia (akon'tia, akon'shia) n. plu. 
[Gk. akontion, small javelin.] 
Threadlike processes of the mesen- 
teric filaments armed with stinging 
cells, in Actinians (zoo/.'). 

acotyledon (a'kotlle'don) . [Gk. a, 
without ; kotyledon, a cup-shaped 
hollow.] A plant without a coty- 
ledon (hot.}. 

acquired character, a modification 
or mutilation, due to disease or to 
use or disuse of a special organ or 
organs, which has actually made its 
appearance during the lifetime of 
the individual (biol.). 

acraspedote (akras'pgdot) a. [Gk. a, 
without ; kraspedon, an edge or 
border.] Having no velum (zool.). 

acrobryous (ak'robrl'us) a. [Gk. akros, 
tip ; bryein, to swell.] Growing at 
the tip only (dot.). 

acrocarpous (ak'rokar'pus) a. [Gk. 
akros, tip ; karpos, fruit.] Having 
the fructification terminating the 
axis (bot.). 

acrocoracoid (ak'rokSr'akoid) n. [Gk. 
akros, tip ; korax, crow ; eidos, 
shape.] A process at the dorsal 
end of the coracoid in birds (zoo!.). 

acrocyst (ak'roslst) n. [Gk. akros, tip ; 
kystis, bladder.] The spherical 
gelatinous cyst formed by the gono- 
phore, when it projects after migra- 
tion on the blastostyle beyond the 
mouth of the gonotheca, for the 
completion of the maturation of the 
generative cells (zool.). 

acrodont (ak'rodont) a. [Gk. akros, 
tip ; odous, tooth.] Appl. teeth 
which are ankylosed by their base 
to the summit of a parapet of bone 

aerodrome (ak'rodrom), acrodromous 
(akrSd'romus) a. [Gk. akros, tip ; 
dromein, to run.] Appl. leaf with 
nerves converging at its point (bot.). 

acrogenous (akr6j'6nus) a. [Gk. akros, 

tip ; genos, offspring.] Increasing 
in growth at the summit or growing 
point (bot.). 

acromial (akro'mial) a. [Gk. akros, 
summit ; omos, shoulder.] Pert. 
the acromion, appl. artery, process, 
ligament, etc. (anat.). 

acromio-clavicular (akro'mio-klavik'- 
ular) a. [Gk. akromion, shoulder- 
summit ; L. claviculus, dim. of 
clavts, key.] Appl. ligaments cover- 
ing the joint between the acromion 
and the clavicle (anat.). 

acromion (akro'mion) n. [Gk. akros, 
summit ; omos, shoulder.] The 
ventral prolongation of the spina 
scapulae (anat.}. 

acropetal (ak'ropeVal) a. [Gk. akros, 
summit ; L. petere, to seek.] Appl. 
leaves or flowers developing from 
an axis so that the youngest arise 
nearest the apex (bot.). 

acrorhagus (akrora'gus) n. [Gk. akros, 
summit ; rhax, grape.] A tubercle 
on the margin of certain Actinians, 
containing nematocysts (zool.). 

acrosarc (ak'rosark) n. [Gk. akros, 
summit ; sarx, flesh.] A pulpy 
berry resulting from the union of 
ovary and calyx (bot.). 

acrosome (ak'rosom) n. [Gk. akros, 
tip ; sotna, body.] Body at the apex 
of a spermatozoon, the apical body 

acrospire (ak'rospir) n. [Gk. akros, 
summit ; speira, something twisted.] 
The first shoot or sprout, being 
spiral, at the end of a germinating 
seed (bot.). 

acrospore (ak'rospor) n. [Gk. akros, 
tip ; sporos, seed.] The spore at 
the end of a sporophore (bot.). 

actinal (ak'tmal, aktfnal) a. [Gk. 
aktis, ray.] Appl. area of an echino- 
derm body in which the tube-feet 
are situated ; appl. the oral area 
with tentacles in Actinaria (zool.). 

actine (ak'tln) n. [Gk. aktis, ray.] A 
star-shaped spicule (zool.). 

actinenchyma (ak'tlngng'kima) n. 
[Gk. aktis, ray ; en, in ; chein, to 
pour.] Cellular tissue having a 
stellate appearance (bot.). 

actinoblast (aktln'oblast) n. [Gk. 
aktis, ray ; blastos, bud.] The 
mother-cell from which a spicule 
is developed (zool.). 



actinocarpous (ak'tinokar'pus) a. [Gk. 
aktis, ray ; karpos, fruit.] Appl. 
plants with flowers and fruit radially 
arranged (bot.). 

actinodrome (aktm'b'drom) a. [Gk. 
aktis, ray ; dramas, a running.] 
Veined palmately (hot.}. 

actinogonidial (ak'tinogonid'ial) a. 
[Gk. aktis, ray ; gonos, offspring.] 
Having radiately arranged genital 
organs as in Stelleroids (zool.). 

actinoid (ak'tinoid) a. [Gk. aktis, ray ; 
eidos, shape.] Rayed, star-shaped. 

actinomere (aktin'omer) n. [Gk. aktis, 
ray ; meros, part.] A radial seg- 
ment (zool.}. 

actinomorphic (ak'tinomor'f Ik), actino- 
morphous (ak'tinomor'fus) a. [Gk. 
aktis, ray ; morphe, shape.] Appl. 
flowers which can be divided into 
like halves by a vertical section 
through the centre ; radiosym- 

actinost (ak'tinost) n. [Gk. aktis, ray ; 
os/eon, bone.] Basal bone of the 
fin-rays in Teleosteans (zool.}. 

actinostome (aktin'ostom) n. [Gk. 
aktis, ray ; stoma, mouth.] The 
five-rayed oral aperture of the star- 
fish (zool.}. 

actlnotrichium (ak'tinotrlk'ium) n. 
[Gk. aktis, ray ; thrix, hair.] A 
delicate unjointed horny fibre of 
mesoblastic origin found at the 
edge of all the fins in adult Tele- 
ostomes, probably homologous with 
the ceratotrichia of Elasmobranchs 

actinotrocha (ak'tfnotro'ka) n. [Gk. 
aktis, ray ; trochos, wheel.] Free- 
swimming larval form of Phoronis 

actinula (aktin'ula) n. [Gk. aktis, 
ray.] A larval stage in some Hydro- 
medusae, in which a coelenteron, 
mouth, and tentacles are formed, 
and cell differentiation has taken 
place before the larva is set free 
from the parent form (zool.}. 

aculeate (aku'leat) a. [L. aculeus, 
prickle, thorn.] Having prickles 
or sharp points (bot.}. 

aculeiform (akule'iform) a. [L. 
aculeus, prickle ; forma, shape.] 
Formed like a prickle or thorn 

aculeus (aku'leus) n. [L. aculeus, 

prickle.] A prickle growing from 
the bark, as in the rose (bot.} ; a 
sting (zool.}. 

acuminate (aku'minat) a. [L. acumen. 
point.] Drawn out into a long 
point ; tapering (bot.} ; pointed 

acuminiferous (akummlf'e'rus) a. [L. 
acumen, point ; ferre, to carry.] 
Having pointed tubercles (zoo/.}. 

acuminulate (ak'umm'ulat) a. [L. 
acuminulus, dim. of acumen, point.] 
Having a very sharp tapering point. 

acute (akut')#. [L. acutus, sharpened.] 
Ending in a sharp point. 

acyclic (asik'llk) a. [Gk. a, without ; 
kyklos, circle.] Appl. flowers in 
which the series of floral leaves are 
arranged in a spiral ; opp. cyclic 

adamantoblast (adaman'toblast) n. 
[L. adamas, diamond ; Gk. blastos, 
bud.] A cell of the internal epi- 
thelial layer of the mammalian 
enamel organ, columnar in shape ; 
the enamel cell ; in many of the 
lower forms the enamel organ con- 
sists only of such cells (zool.}. 

adambulacral (ad'ambula'kral) a. 
[L. ad, to ; ambulare, to walk.] 
Appl. ossicles or structure adjacent 
to the ambulacral areas in Echino- 
derms (zool.}. 

adaptation (adapta'shun) n. [L. ad, 
to ; aptare, to fit.] The process by 
which an organism becomes fitted 
to its environment ; a structure or 
habit fitted for some special environ- 
ment ; the fitting of cutaneous and 
other sensations to a point when 
discomfort ceases, as the physio- 
logical zero in the case of adapta- 
tion to temperature (phys.}. 

adduction (aduk'shun) n. [L. ad, to ; 
ducere^ to lead.] The movement 
towards the median axis (phys.}. 

adductor (aduk'tor) n. [L. ad, to ; 
ducere, to lead.] Any muscle which 
brings one part towards another 

adeciduate (adesld'uat) a. [L. a, 
away from ; df, from ; cadere, to 
fall.] Not falling, or coming 
away, appl. evergreens (bot.) ; 
appl. placenta (zool.). 

adelocodonic (ad'61okod6n'lk, ade'- 
I6kod6n'lk) a. [Gk. adelos, con- 



cealed; kodon, bell.] Appl. the 
undetached medusome of certain 
Gymnoblastea, which degenerates 
after discharging ripe sexual cells, 
as opp. the free or phanerocodonic 
gonophore or medusome (zoo/.). 
adelomorphic (ad'elomor'fik, ade'- 
I6m6r'(ik) a. [Gk. adelos, con- 
cealed ; morphe, shape.] Indefinite 
in form ; appl. central cells of peptic 
glands (anat.). 

adelphous (adel'fus) a. [Gk. adel- 
phos, brother.] Joined together in 
bundles (hot.} ; used in compounds 
monadelphous and diadelphous, 
which see. 

adenocheiri (ad'gnokl'n, -re) n. plu. 
[Gk. aden, gland ; cheir, hand.] 
Elaborate accessory copulatory 
organs, outgrowths of the atrial 
walls in the turbellarian genus 
Artioposthia (zool.}. 
adenodactyli (ad'Snodak'till, -le) n. 
plu. [Gk. aden, gland ; daktylos, 
finger.] Adenocheiri, which see 

adenoid (ad'gnoid) a. [Gk. aden, 
gland ; etdos, shape.] Pert, or 
resembling a gland ; pert, or re- 
sembling lymphoid tissue. 
adenophore (ad'enofor') n. [Gk. aden, 
gland ; pherezn, to carry.] The stalk 
of a nectar gland (bot.}. 
adenophyllous (ad'enb'fil'Cis) a. [Gk. 
aden, gland ; phyllon, leaf.] Bear- 
ing glands on the leaves (hot.}. 
adenopodous (adenop'odus) a. [Gk. 
aden, gland ; pous, foot.] Bearing 
glands on the peduncles (bot.}. 
adenostemonous (ad'enostgrn'onus) a. 
[Gk. aden, gland ; steinon, a spun 
thread.] Having glands on the 
stamens (bot.}. 

adesmy (adgs'mi) n. [Gk. adesmos, 
unfettered.] A break or division 
in an organ usually entire (bot.}. 
adetopneusic (ad'gtopnu'sik) a. [Gk. 
adetos, free ; pnein, to breathe.] 
Having papulae or dermal 
branchiae occurring beyond the 
abactinal surface, as in certain of 
the Stelleroids (zool.}. 
adherent (adhe'rgnt) a. [L. ad, to ; 
haerere, to stick.] Pert, union of 
parts which are normally separate, 
as calyx and ovary ; adnate (dot.}. 
adhesion (adhe'zhun) n. [L. ad, to ; 

haerere, to stick.] Condition of 
being united to, or separate from, 
one another, appl. elements of a 
whorl (bot.}. 

adhesive cells, Glandular or special- 
ized cells found in various animals; 
on the tentacles of Ctenophores, on 
the epidermis of certain Turbel- 
larians, on the pedal disc of 
Hydra, etc. 

adipose (ad'Tpos) a. [L. adeps, fat.] 
Pert, or designating animal fat ; 
fatty (phys.}. 

adipose tissue, the special animal 
tissue for the formation and storage 

adminicula (ad'mimk'ula) n. plu. [L. 
adminiculum, support.] Spines of 
certain pupae, assisting in wriggling 
motion (zoo!.). 

adnate (adnat') a. [L. ad, to ; gnatus, 
born.] Pert, or designating the con- 
dition of being closely attached to 
the side of the petiole or stalk, as 
in the case of stipules or leaves ; 
designating the condition of the 
anther when its back is attached 
throughout its whole length to the 
filament, or to its continuation the 
connective (bot.}. 

adnexa (adngk'sa) n. plu. [L. ad, to ; 
nectere, to bind.] Certain structures 
or parts of structures closely related 
to any organ (anat.}. 

adnexed (adneksf) a. [L. ad, to ; 
nectere, to bind.] Reaching to the 
stem only (bot.}. 

adoral (ado'ral) a. [L. ad, to ; os, 
mouth.] Near the mouth, or pert. 
the mouth (zoo!.). 

ad-radius (adra'diiis) n. [L. ad, to ; 
radius, radius.] The radius in 
Coelenterates midway between the 
perradius and the interradius, a 
radius of the third order (zool.). 

adrectal (adrgk'tal) a. [L. ad, to ; 
rectum, rectum.] Near to or 
closely connected with rectum 

adrenal (adre'nal) a. [L. ad, to ; 
renes, kidneys.] Suprarenal. 

adrenalin (adre'nalTn), adrenaline 
(adre'nalin, adre'nalen) n. [L. ad, 
to ; renes, kidneys.] A crystalline 
substance obtained from suprarenal 
extract (phys.}. 

adrostral (adros'tral) a. [L. ad, to ; 


rostrum, beak.] Near to or closely 
connected with the beak or rostrum 

adsorption (iidsorp'shun) n. [L. ad, 
to ; sorbere, to suck in.] The con- 
centration of a substance in solution 
in a liquid on a surface in contact 
with the surface of another phase ; 
the adhesion of molecules to solid 
bodies (phys.). 

aduncate (adung'kat) a. [L. aduncus, 
hooked.] Crooked ; bent in the 
form of a hook. 

advehent (ad've'he'nt) a. [L. adve- 
here, to carry to.] Appl. veins, 
same as afferent (anat.). 

adventitious (advgntish'iis) a. [L. ad, 
to ; venire, to come.] Accidental ; 
appl. organs arising in abnormal 
positions (hot.}. 

aecidiospores (esld'iosporz', as-) n. plu. 
[L. aecidium, cup ; Gk. sporos, seed.] 
The spores contained in an aeci- 
dium or clustercup (bot.). 

aecidium (estd'ium, as-) n. [L. aeci- 
dium, cup.] A cup-shaped structure 
containing simple sporophores, 
bearing rows of spores (bot.). 

aegithognathous (e'jlthog'nathus, a'- 
glthogna'thus) a. [Gk. aegithos, 
hedge - sparrow ; gnathos, jaw.] 
With maxillo - palatines separate, 
vomers forming a wedge in front 
and diverging behind ; appl. a type 
of palate found in the Carinatae 

aerial (ae'rtal) a. [L. aer, air.] In- 
habiting the air ; appl. roots grow- 
ing above ground, e.g. from stems 
of ivy, for purposes of climbing ; 
also to small bulbs appearing in 
the axils of the leaves of certain 
plants (bot.). 

aerobe (a'eYob) n. [Gk. aer, air ; 
bios, life.] An organism which 
grows only in the presence of 
oxygen ; appl. bacteria. 

aerobic (a'erob'ik) a. [Gk. aer, air ; 
bios, life.] Thriving only in abund- 
ance of oxygen (bact.). 

aerocyst (a'grb'sTst) n. [Gk. aer, air ; 
kystis, bladder.] An air vesicle 
of Algae (bot.). 

aerophyte (a'6roflt) n. [Gk. aer, air ; 
phyton, plant.] A land-plant grow- 
ing attached to another plant ; an 

aerostat (a'grostat) n. [L. aer, air ; 
stare, to stand.] An air-sac in 
insect body or in bird-bone (zool.). 

aerostatic (a'Srostat'ik), a. [L. aer, 
air ; stare, to stand.] Pneumatic ; 
containing air-spaces (zool.). 

aerotaxis (a'grotak'sls) . [Gk. aer, 
air ; taxis, arrangement.] The 
movement of bacteria and other 
micro-organisms towards or away 
from oxygen (phys.). 

aerotropism (aerot'ropizm) n. [Gk 
aer, air ; trepein, to turn.] The 
reaction of plants to gases (bot.). 

aesthacyte (es'thaslt) n. [Gk. ais- 
thesis, sensation ; kytos, hollow.] 
A sensory cell of primitive animals, 

aesthesia (gsthe'zla) n. [Gk. aisthesis, 
sensation.] Sensibility. 

aestival (eVtlval, estl'val) a. [L. 
aestas, summer.] Produced in, or 
pert, summer. 

aestivation (eVtiva'shun) n. [L. aesti- 
uus, pert, summer.] The mode in 
which the different parts of the 
flower are disposed in the flower- 
bud ; praefloration ; torpor during 
summer as in the case of some 

aethalium (etha'llum, ath-) n. [Gk. 
aithahs, soot.] An aggregation of 
plasmodia to form a compound fruit 
in Mycetozoa. 

aetiology (etI61'6jl) n. [Gk. aitia, 
cause ; logos, discourse.] A branch 
of biology dealing with causes. 

afferent (af'erent) a. [L. afferre, to 
bring.] Appl. nerves carrying im- 
pulses to the nervous centres ; appl. 
blood-vessels carrying blood to any 
particular organ or set of organs 

affinity (afm'itl) n. [L. affinis, related 
to.] Relationship ; similarity in all 
essential organs (biol.). 

aflagellar (a'flajgl'ar) a. [Gr. a, 
without ; L. flagelluni, a whip.] 
Without a flagellum, a whip-like 
appendage in certain unicellular 
organisms ; appl. the end of a 
trypanosome not furnished with a 
flagellum (zool.}. 

afterbirth (af'terberth) n. [A.S. 
aefter, behind ; beran, to bring 
forth.] Placenta and foetal mem- 
branes expelled after the young is 
born (anal!.). 




aftershaft (af'tershaft) . [A.S. 
aefter, behind ; shaft.] A small 
tuft of down in the neighbourhood 
of the superior umbilicus in the 
feathers of most birds ; in certain 
birds (e.g. moas, emu, cassowary) 
a second vane, which, usually 
shorter, but sometimes of equal 
length to the vane proper, arises 
near the superior umbilicus (zool.}. 

agametes (ag'amets) n. plu. [Gk. a, 
without ; games, marriage.] Amoe- 
bulae which develop directly into 
adults without syngamy (zool.}. 

agamic (agam'lk) a. [Gk. a, without ; 
games, marriage.] Asexual ; appl. 
to a parthenogenic race (biol.} ; 
cryptogamic (bot.}. 

agamobium (ag'amS'bium) n. [Gk. 
a, without ; games, marriage ; bios, 
life.] The asexual stage in meta- 
genesis (zool.} ; the sporophyte 

agamogenesis (ag'amqje'n'e'sis) n. [Gk. 
a, without ; games, marriage ; 
genesis, generation.] Partheno- 

agamogenetic (ag'amojSngt'ik) a. 
[Gk. a, without ; games, marriage ; 
genesis, birth.] Appl. asexual re- 

aganiogony (ag'amog'oni) n. [Gk. a, 
without ; games, marriage ; genes, 
offspring.] Schizogony, or repro- 
duction without sexual process 

agamont (ag'amont) n. [Gk. a, with- 
out ; games, marriage ; on, being.] 
A schizont, or that stage which 
gives rise to agametes (biol.}. 

agamous (ag'amus) a. See agamic. 

agglomerate (agl8m'6rat) a. [L. ad, 
to ; glomus, ball.] Clustered, as a 
head of flowers. 

agglutination (aglootina'shun) . [L. 
ad, to ; glutinare, to glue.] The 
forming of clumps or floccules by 
bacteria distributed in a medium, 
and their simultaneous loss of 
mobility (bact.}. 

agglutinin (agloot'inm) n. [L, ad, 
to ; glutinare, to glue.] A sub- 
stance which is supposed to cause 
agglutination (phys.}. 

aggregate (ag'rggat) a. [L. ad, to ; 
gregare, to collect into a flock.] 
Formed in a cluster (bot., zool.}. 

aggregate fruit, a fruit formed 
from the apocarpous gynoecium 
of a single flower, as the raspberry. 

aggregation (agrgga'shun) n. [L. ad, 
to ; gregare, to collect.] The 
peculiar movement of the proto- 
plasm in the cells of the tentacles 
or tendrils of sensitive plants, which 
being due to previous contact, causes 
the tentacle or tendril to bend 
towards the point where the stimu- 
lus was applied (phys.}. 

aggressin (agres'm) n. [L. aggressus, 
attacked.] A toxic substance pro- 
duced by pathogenic organisms 
inhibiting the defensive reactions 
of the host (phys.}. 

aglossate (aglos'-at) n. [Gk. a, with- 
out ; glossa, tongue.] Having no 
tongue (zool.}. 

agnathostomatous (agnath'ostonY- 
atus) a. [Gk. a, without ; gnathos, 
jaw ; stoma, mouth.] Having the 
mouth unfurnished with jaws, as in 
the lamprey (zool.}. 

agnathous (agnath'us) a. [Gk. a, 
without ; gnathos, jaw.] Having 
no jaw (zool.}. 

agrostology (ag'rostol'ojl) n. [Gk. 
agrostis, grass ; logos, discourse.] 
That part of botany dealing with 
the systematic treatment of grasses 

air-bladder (ar'-blad'er) n. [L. aer, 
air; A.S. bleedre, bladder.] The 
swim-bladder, an air-sac formed by 
an outgrowth from the alimentary 
canal in many fishes (zool.}. 

air-cells, thin-walled cavities in the 
ethmoidal labyrinth ; numerous 
cavities in the mastoid (anat.}. 

air-sacs, spaces filled with air and 
connected with the lungs, which 
increase the respiratory coefficient, 
and probably lessen the specific 
gravity in birds. 

akaryote (aka/iot) n. [Gk. a, without ; 
karyon, nut, nucleus.] A cell in 
which the nucleoplasm has not 
collected together to form a nu- 
cleus ; a non-nucleated cell (cyt.}. 

akinete (^'kinet', aVinet) n. [Gk. a, 
not ; kinein, to move.] A resting 
cell in certain green Algae, which 
will later reproduce (bot?). 

ala (a'la) n. [L. ala, wing.] Any 
winglike projection, e.g. of vomer 




(anat.) ; the lateral petal of a 
papilionaceous flower ; the mem- 
branous expansion on some seeds 
or fruits (bot.). 

alar (a'lar) a. [L. ala, wing.] Wing- 
like ; pert, alae ; axillary (bot.) ; 
appl. ligaments, cartilages, etc. 

alary (a'l&rT) a. [L. ala, wing.] 

alate (a'lat) a. [L. ala, wing.] Broad- 
lipped, appl. shells ; appl. a spicular 
system in Calcarea which is sagit- 
tal because of inequality of angles 

albescent (albeVgnt) a, [L. albescere, 
to grow white.] Growing whitish. 

albicant (al'bikant) a. [L. albicare, 
to grow white.] Becoming white. 

albinism (al'bimzm) n. [L. albus, 
white.] The absence of pigmenta- 
tion (zoo!.) ; state of having colour- 
less chromatophores. 

albino (albino, albe'no) n. [Sp. 
albino, white, from L. albusl\ A 
person with congenital deficiency 
of pigment in the skin, hair, and 
eyes (anat.) ; any animal with a 
similar deficiency on its body 
(zool.) ; a plant with colourless 
chromatophores, due to absent 
chloroplasts or undeveloped chro- 
moplasts (bot.). 

albumen (albu'men) n. [L. albumen, 
white of egR.] The white of egg 
(zool.) ; nutritive material stored in 
the embryo (bot.). 

albumin (albu'mln) n. [L. albumen, 
white of egg.] A protein occurring 
in blood serum, milk, and many 
animal and vegetable tissues (phys.). 

albuminous (albu'minus) a. [L. albu- 
men, white of egg.] Pert, having, 
or of the nature of, albumen or 

alburnum (albur'num) n. [L. albus, 
white.] Sapwood or splintwood, 
the soft white substance between 
inner bark (cambium) and true 
wood (duramen) ; the outer young 
wood of a dicotyledonous stem 

alecithal (aleVithal) a. [Gk. a, with 
out ; lekithos, yolk.] Appl. ova 
with little or no yolk (zool.). 

aleurone (alu'ron) n. [Gk. aleuron, 
flour.] Appl. proteid grains found 

in general protoplasm and used as 
reserve food-materials (bot.). 

alexin (aleVsin) n. [Gk. alexein, to 
ward off.] A substance in the 
blood which destroys bacteria 

algin (al'jin) n. [L. alga, seaweed.] 
A substance of a gelatin character 
obtained from certain Algae (phys.). 

algoid (al'goid) a. [L. alga, plant ; 
Gk. eidos, shape.] Pert, resembling 
or of the nature of an Alga (bot.). 

algology (algol'oji) n. [L. alga, sea- 
weed ; Gk. logos, discourse.] The 
study of seaweeds or Algae (bot.). 

alima (al'ima) . [Gk. halimos, pert. 
sea.] A larval stage of certain 
Crustacea, e.g. Squilla (zool.). 

alimentary (al'Ime'n'tari) a. [L. alere, 
to nourish.] Pert, the nutritive 
functions ; appl. canal, tract, 
system, etc. 

alisphenoid (al'isfe'noid) . [L. a/a, 
wing ; Gk. sphen, wedge ; eidos, 
form.] The wing-like portion of 
the sphenoid forming part of the 

alitrunk (al'itrungk) n. [L. ala, wing ; 
truncus, trunk.] The thorax of an 
insect when fused with the first 
segment of the abdomen. 

allantois (Slan'tois) n. [Gk. alias, 
sausage.] An embryonic organ, a 
membranous bag arising from the 
posterior part of the alimentary 
canal in the higher vertebrates, 
and acting as an organ of respira- 
tion or nutrition or both, and 
usually uniting with the chorion 

allassotonic (alas'otfin'ik) a. [Gk. 
allassein, to change ; tonos, strain.] 
Induced by stimulus, appl. move- 
ments of grown plants. 

allelomorph (ale'lomorf) n. [Gk. alle- 
lon, one another ; morphe, form.] 
In Mendelian inheritance one of 
any pair of alternative characters 

alliaceous (alta'shus) a. [L. allium, 
garlic.] Pert, the allium or garlic 
family ; having a smeN or taste 
like garlic (bot?). 

allogamy (alfig'aml) n. [Gk. allos, 
other ; gamos, marriage.] Cross- 
fertilization, as opp. autogamy 




alloiogenesis (al'oiojen'esis) n. [Gk. 
alloios, different ; genesis, descent.] 
The alternation in a life-history of 
a sexual and a non-sexual form ; 
alternation of generations (biol.}. 

allopelagic (al'opelaj'ik) a. [Gk. allos, 
other ; pelagos, sea.] Pert, organ- 
isms found at any depth of the sea 
uninfluenced by heat or cold (biol.}. 

alloplasmatic (al'dplasmat'ik) a. [Gk. 
allos, other ; plasma, something 
moulded.] Appl. the differentiated 
portion of cell protoplasm (cyt.). 

alloplast (al'oplast) n. [Gk. allos, 
other ; plastos, formed.] A morpho- 
logical cell-unit of more than one 
kind of tissue (cyt.}. 

alluvial (alu'vial, aloo-) a. [L. alluere, 
to wash to.] Pert, or found in 
deposits laid down by running 
water (pal.}. 

alsinaceous (alsina'shiis) a. [Gk. 
alsine, chickweed.] Appl. a poly- 
petalous corolla where intervals 
occur between the petals, as in the 
chickweed (bot.}. 

alteration theory, explains the 
electromotive forces of nerve and 
musclebyalterations in the chemical 
composition of the tissue at the 
cross-section (phys.}. 

alternate (alter'nar, olteVnat) a. [L. 
alternus, one after another.] Appl. 
leaves or branches occurring at 
different levels on opposite sides of 
the stem (bot.}. 

alternation of generations, the 
occurrence in one life-history of 
two or more different forms differ- 
ently produced, as in the polypoid 
and medusoid stages of Hydroids 

alternation of parts, it is the general 
rule that leaves of the different 
whorls alternate in position with 
each other, sepals with petals, 
stamens with petals (tot.). 

alternlplnnate (alteYnipin'at, 61-) a. 
[L. alternus, one after another ; 
pinna, wing.] Appl. leaflets or 
pinnae arising alternately on each 
side of the mid-rib (hot}. 

altrices (altrl'sez, al'trlsgz) n. plu. 
[L. altriX) nourishes] Appl. birds 
whose young are hatched in a very 
immature condition (zool.}. 

alula (al'ula) n. [L. alula, dim. of 

ala, wing.] A small lobe separated 
off from the wing-base on its pos- 
terior edge in certain insects ; false 
wing of birds (zool.}. 

alveola (alve'dla) n. [L. alveolus, a 
small cavity.] A pit on the surface 
of an organ (bot.}. 

alveolar (alve'olar) a. [L. alveolus, 
a small pit.] Pert, a tooth socket 
or alveolus ; appl. artery, nerve, 
process, canal, in connection with 
the jaw-bone (anat.) ; appl. a par- 
ticular stage in protoplasm ; and to 
small cavities in the lungs (zool.} ; 
alveolar point see prosthlon. 

alveolate (alve'olat) a. [L. alveolatus, 
pitted.] Deeply pitted or honey- 

alveolus (alve'olus) . [L. alveolus, 
a small pit.] A tooth socket or 
small pit or depression (anat.) ; the 
pyramidal ossicle supporting a tooth 
in the sea-urchin (zool.}. 

alveus (al'veus) n. [L. alveus, cavity.] 
A thin white layer on the ventricular 
surface of the hippocampus (anat.}. 

amacrine (am'akrin) a. [Gk. a, not ; 
makros, long ; fs, fibre.] Appl. 
cells occurring in the inner nuclear 
layer of the retina (anat}. 

ambidextrous (am'bidgk'strus) a. [L. 
ambo, both ; dexter, right.] Able 
to use both hands with equal ease. 

ambiens (am'bignz) n. [L. ambire, to 
go round.] A thigh muscle in cer- 
tain birds, the action of which causes 
the toes to grasp the perch (zool.}. 

ambiparous (amblp'arus) a. [L. ambo, 
both; parere, to beget.] Appl. 
buds as they contain the beginnings 
of both flowers and leaves (hot.}. 

ambisporangiate (am'blsporan'jTat) 
a. [L. ambo, both ; Gk. sporos, 
seed ; anggeion, box.] Appl. plants 
with sporophylls bearing both 
megasporangia and microsporangia 

ambital (am'bital) a. [L. ambire, to 
go round.] Appl. interambulacral 
and antambulacral plates of Aster- 
oids ; the outer skeleton of arm of 
Ophiuroids (zool.} . 

ambitus (am'bitus) n. [L. ambire, to 
go around.] The outer edge or 
margin of a thing ; the outline of 
an echinoid shell viewed from the 
apical pole (zool.}. 




amboceptor (am'bose'p'to'r) n. [L. 
ambo, both ; capere, to take.] An 
antibody or specific immune body 
necessary for the ferment-like action 
of the complement on a toxin or 
a red blood corpuscle (phys.}. 

ambulacra (am'bula'kra) n. plu. [L. 
ambulare, to walk.] Locomotor 
tube-feet of Echinoderms (zool.}. 

ambulacralia (am'bulakra'lia) n. plu. 
[L. ambulare, to walk.] Ambu- 
lacral plates, i.e. plates through 
which the tube-feet protrude (zool.}. 

ambulacriform (ambulak'riform) a. 
[L. ambulare, to walk ; forma, 
shape.] Having the form or appear- 
ance of ambulacra (zool.}. 

ameliflcation (amel'ifika'shun) n. 
[M.E. amell, enamel ; L.facere, to 
make.] Formation of tooth-enamel 

aineloblast (ameToblast) n. [M.E. 
amell, enamel ; Gk. blastos, bud.] 
A columnar or hexagonal cell about 
five times as long as it is broad, an 
enamel-forming cell ; a cell of the 
internal epithelium of the enamel 
organ (anat.}. 

amentaceous (amgnta'shus) a. [L. 
amentum, a thong.] Appl. plants 
bearing aments or catkins (bot.). 

amentiferous (amgntlferus) a. [L. 
amentum, a thong ; ferre, to carry.] 

amentum (amen'tum) n. [L. amentum, 
a thong.] A catkin, consisting of 
a bracted axis bearing unisexual 
flowers as in the poplar and willow 

ametabolic (amSt'abol'ik) a. [Gk. a, 
without ; metabole, change.] Appl. 
insects that do not pass through 
any marked metamorphosis (zool.}. 

amicron (amik'ron)' n. [Gk. a, with- 
out ; mikros, small.] An element 
so small that even the ultramicro- 
scope can only indicate it as a 
diffuse illumination in the track of 
the beam ; cf. submicron (phys.}. 

amlcronucleate (ami'kronu'kleat) a. 
[Gk. a, without ; mikros, small ; L. 
nucleus, kernel.] Appl. fragments 
of certain Protozoa in which there 
is no micronucleus (zool.}. 

amitosis (amito'sis) n. [Gk. a, with- 
out ; mitos, thread.] Cell-division 
and cleavage of the nucleus with- 

out the thread-like formation of the 
nuclear material (cyt.}. 

ammonltiferous (am'onltlf'e'rus) a. 
[Gk. Amman, Jupiter; L. ferre, to 
carry.] Containing the fossil re- 
mains of Ammonites (pal.}. 

amoeba (ame'ba) n. [Gk. amoibe, ex- 
change.] A protozoon in which the 
shape is subject to constant altera- 
tions due to the formation and 
retraction of pseudopodia (zool.}. 

amoebifonn (ame'biform) a. [Gk. 
amoibe, change ; L. forma, shape.] 
Shaped like or resembling an 
amoeba (biol.}. 

amoebocyte (ame'boslt) . [Gk. 
amoibe, change ; kytos, hollow.] 
Any cell having the shape or pro- 
perties of an amoeba, especially 
certain cells in the coelom of Ech- 
inoderms ; a leucocyte (zool.}. 

amoeboid (ame'boid) a. [Gk. amoibe, 
change ; eidos, shape.] Resembling 
an amoeba in shape or in properties 

amoebula (ame'bula) n. [Gk. amoibe, 
change.] The swarm-spore of a 
protozoan when furnished with 
pseudopodia (zool.}. 

amorphous (am&r'fus) a. [Gk. a, 
without ; morphe, shape.] Inde- 
terminate, or of irregular form. 

amphiarthrosis (am'fiarthro'sls) n. 
[Gk. amphi, both ; arthron, joint.] 
A slightly movable articulation, as 
a symphysis or syndesmosis (anat.}. 

amphiaster (am'ftas'te'r) n. [Gk. 
amphi, both ; aster, star.] The 
two asters connected by the 
achromatic spindle formed in 
mitotic cell division (cyt.). 

amphibious (amfib'ius) a. [Gk. 
amphi, both ; bios, life.] Adapted 
for life either on land or in water 

amphiblastic (am'fiblas'tlk) a. [Gk. 
amphi, both ; blastos, bud.] Having 
unequal segmentation, appl. telo- 
lecithal ova with complete segmen- 
tation (biol.}. 

amphiblastula (am'fiblas'tula) n. [Gk. 
amphi, both ; blastos, bud.] Stage 
in the development of certain 
sponges, in which the posterior 
end of the embryo is composed 
of granular archaeocytes, and the 
anterior end of flagellate cells (zool.}. 




amphibollc (am'fibol'ik) a. [Gk. 
amphi, both ; ballein, to throw.] 
Capable of turning backwards or 
forwards, as the outer toe of certain 
birds (zool.). 

ainphlcarpous (am'fikar'pus) a. [Gk. 
amphi, both ; karpos, fruit.] Pro- 
ducing fruit of two kinds (bot.). 

ampbicoelous (am'fise'lus) a. [Gk. 
amphi, both ; koilos, hollow.] Con- 
cave on both surfaces ; appl. verte- 
brae with the anterior and posterior 
surfaces of the centra hollow (zoo/.}. 

amphicondylous (am'fikon'dilus) a. 
[Gk. amphi, both ; kondylos, knob.] 
Having two occipital condyles 

amphidisc (am'fidisk) n. [Gk. amphi, 
both ; diskos, round plate.] Grapnel- 
shaped spicules protecting the 
gemmules of some freshwater 
sponges (zoo/.). 

amphigastria (am'figas'tria) n. plu. 
[Gk. amphi, both ; gaster, stomach.] 
Ventral rudimentary leaves of 
foliose liverworts (dot.). 

amphigony (amfig'oni) n. [Gk. 
amphi, both ; gonos, offspring.] 
Sporogony or reproduction in- 
volving two individuals ; cf. mono- 
gony (zool. ). 

amphikaryon (am'fikar'ion) n. [Gk. 
amphi, both ; karyon, nut.] An 
amphinucleus, a type of nucleus 
characterized by a large karyo- 
some, in reference to the supposed 
encapsuling of the kinetic nucleus 
by the trophic nucleus (cyt.). 

amphimixis (am'fimlk'sis) n. [Gk. 
amphi, both ; mixis, mingling.] 
The mingling of paternal and 
maternal characteristics by the 
union of the male and female 
pronucleus in fertilization (biol.). 

amphiodont (am'ftodont) n. [Gk. 
amphi, both ; odous, tooth.] Appl. 
an intermediate state of mandible 
development in stag-beetles (zool.). 

amphiont (am'fiSnt) n. [Gk. amphi, 
both ; on, being.] A zygote or 
sporont formed by the coming 
together of two individuals (zool.). 

amphiplatyan (am'fiplat'ian) a. [Gk. 
amphi, both ; platys, flat.] Flat 
on both ends ; appl. centra of 
vertebrae (zool.). 

amphipneustous (am'flpnus'tus) a. 

[Gk. amphi, both ; pnein, to 
breathe.] Having both gills and 
lungs throughout the life-history ; 
also appl. the condition in most 
dipterous larvae of an open anterior 
and posterior pair of spiracles with 
the intermediate pairs closed (zool.). 

amphipodous (amfip'odus) a. [Gk. 
amphi, both ; pous, foot.] From 
Amphipoda, an order of Crustacea, 
of which the anterior three pairs 
of abdominal appendages are more 
strongly developed for swimming, 
the remaining three pairs being 
adaptedforjumping, hence, having 
feet both for walking and for 
swimming (zool.). 

amphipyrenin (am'fiplre'mn) n. [Gk. 
amphi, both ; Pyren, stone of a 
fruit] The substance of which 
the nuclear membrane in a cell is 
composed (biol.). 

ampb.irb.inal (am'firl'nal) a. [Gk. 
amphi, both ; rhis, nose.] Having 
two nostrils (zool.). 

amphisarca (am'ffsar'ka) n. [Gk. 
amphi, both ; sarx, flesh.] A 
superior indehiscent many-seeded 
fruit with pulpy interior and woody 
exterior (bot.). 

amphispermous (am'fispSr'mus) a. 
[Gk. amphi, both ; sperma, seed.] 
Having the seed closely surrounded 
by the pericarp (bot.). 

ampbispore (am'fispor') n. [Gk. 
amphi, both ; sporos, seed.] A 
reproductive spore which functions 
as a resting spore in certain Algae 

ampbisternous (am'fisteYnus) a. [Gk. 
amphi, both ; sternon, the breast.] 
Appl. a type of sternum structure 
in the Atelostomata (zool.). 

amphistomatic (am'fistomat'ik) a. 
[Gk. amphi, both ; stoma, mouth.] 
Having stomata on both surfaces, 
appl. certain types of leaves (bot.). 

amphistomous (amfis'tomus) a. [Gk. 
amphi, both ; stoma, mouth.] Hav- 
ing a sucker at each end of the 
body, as in certain worms (zool.). 

amphistylic (am'fistil'ik) a. [Gk. 
amphi, both ; stylos, pillar.] Hav- 
ing the lower jaw connected with 
the skull by both hypid and quad- 
rate, or by both hyoid and palato- 
quadrate (zool.). 




amphithecium (auifithe'shiuuij n. 
[Gk. amphi, both ; thekion, box.] 
The peripheral layer of cells in the 
sporangia of mosses (bot.). 

amphitoky (amfit'oki) n. [Gk. amphi, 
both ; tokos, birth.] Partheno- 
genetic reproduction of both males 
and females (zoo!.). 

amphitriaene (am'fitrl'en) n. [Gk. 
amphi, both ; triaina, trident.] A 
double trident-shaped spicule (zool.). 

amphitrocha (amfit'roka) n. [Gk. 
amphi, both ; trochos, wheel.] A 
free-swimming annelid larva with 
two rings of cilia (zool.). 

amphitropal (amfit'ropal) a. [Gk. 
amphi, both ; trope, turning.] 
Having the ovule inverted, with the 
hilum in the middle of one side 

amplectant (amplek'tant) a. [L. 
amplecti, to embrace.] Clasping 
or winding tightly round some 
support, as tendrils in certain 
plants (bot.). 

amplexlcaul (ampleVsikol) a. [L. 
amplecti, to embrace ; caulis, stem.] 
Clasping or surrounding the stem, 
as the base of a leaf (dot.). 

ampliate (am'pliat) a. [L. ampliatus, 
made wider.] Having the outer 
edge of the wing prominent, as in 
certain insects (zool.). 

ampulla (ampool'a, -pul'-) n. [L. 
ampulla, flask with narrow neck 
and globular body.] A membran- 
ous vesicle ; part of the dilated 
tubule in the mammary gland ; the 
dilated portion at one end of each 
of the semi-circular canals of the 
ear (anat.) ; the internal reservoirs 
on the ring canal of the water- 
vascular system in Echinoderms ; 
the terminal vesicle of sensory 
canals of Elasmobranchs (zool.) ; 
the submerged bladder of Utri- 
cularia (bot). 

ampullaceal (ampula'seal) a. [L. 
ampulla, flask.] Flask-shaped, 
appl. arachnid spinning glands 
which furnish silk for foundations, 
lines, and radii (zool.). 

ampullaceous (ampula'shus) a. [L. 
ampulla, flask.] Flask-shaped. 

ampullary (ampool'ari, -pul'-) a. [L. 
ampulla, flask.] Pert, or resembling 
an ampulla (anat.). 

ainyelinic (amielin'ik) a. [Gk. a, 
without ; myelos, marrow.] Appl. 
non-medullated nerve-fibres (anat.). 

amygdala (amig'dala) n. [L. from 
Gk. amygdale, almond.] One of 
the palatal tonsils ; a rounded lobe 
at the side of the vallecula of the 
cerebellum (anat.). 

amyloplast (am'iloplast') n. [L. 
amylum, starch ; Gk. plastos, 
formed.] A leucoplast or colourless 
starch-forming granule in plants 

amyloplastid, amyloplast. 

amylum (am'ilum) n. [L. amylum, 
starch.] Starch. 

anabiosis (an'ablo'sis) n. [Gk. ana, 
up ; bios, life.] Resuscitation after 
apparent death ; power of revivifica- 
tion as seen in certain Tardigrada 

anabolism (anab'olizm) n. [Gk. ana, 
up ; ballein, to throw.] The con- 
structive chemical processes going 
on in living organisms whereby food- 
material is transformed into proto- 
plasm (phys.). 

anacrogynous (anakroj'mus) a. [Gk. 
an, not ; akros, apex ;gyne, female.] 
Appl. certain liverworts in which 
the archegonia or female repro- 
ductive bodies do not arise at or 
near the apex of a shoot (bot.). 

anacromyoldlan (anak'romioid'ian) a. 
[Gk. ana, up ; akros, apex ; mys, 
muscle.] With the syringeal 
muscles attached -at the dorsal 
ends of the bronchial semi-rings 

anaerobe (ana'Srob) n. [Gk. an, with- 
out ; aer, air ; bios, life.] An organ- 
ism capable of living in the absence 
of free-oxygen ; appl. bacteria. 

anaesthesia (angsthe'zla) n. [Gk. an, 
without ; aisthesis, feeling.] In- 
sensibility (phys.). 

anagenesis (an'aje'n'e'sis) n. [Gk. ana, 
again ; genesis, birth.] Regenera- 
tion of tissues (phys.). 

anal (a'nal) a. [L. anus, anus.] Pert. 
or situated at or near the anus ; 
appl. posterior median unpaired 
ventral fin of fishes, margin and 
nerve of insect wing, posterior ven- 
tral scute of reptiles (zool.). 

analogues (an'a!6gz) n. plu. [Gk. 
analogia, proportion.] Organs of 




different plants or animals with 
similar function but of dissimilar 
origin (biol.}. 

anamorphosis (an'amor'fosis) n. [Gk. 
ana, again ; morphe, form.] The 
evolution from one type to another 
through a long series of gradual 
changes (biol.}. 

anangian (anan'jian) a. [Gk. a, 
without ; anggeion, vessel.] Appl. 
worms without a vascular system. 

anaphase (an'afaz) n. [Gk. ana, up ; 
phasis, appearance.] A stage in 
mitosis during the divergence of 
the daughter-chromosomes (biol.}. 

anaphylaxis (an'afilak'sis) . [Gk. 
ana, up ; phylax, guard.] Con- 
dition of being hypersensitive to a 
serum, caused by the first or sensi- 
tizing dose (phys.}. 

anapophysis (an'apofisis) n. [Gk. 
ana, up ; apo, from ; phyein, to 
grow.] A small dorsal projection 
rising near the transverse processes 
in lumbar vertebrae (anat.}. 

anarthrous (anar'thrus) a. [Gk. a, 
without ; arthron, joint.] Having 
no distinct joints (zool.}. 

anastates (an'astats) n. plu. [Gk. 
ana, up ; stanein, to make to 
stand.] The various materials 
that arise owing to metabolism in 
a cell, in the formation of complex 
from simple substances (biol.}. 

anastomosis (anas'tomo'sis) n. [Gk. 
ana, up ; stoma, mouth.] Union of 
ramifications of the leaf- veins (bot.} ; 
union of blood-vessels arising from 
a common trunk ; union of nerves ; 
formation of a network or mesh- 
work (anat.}. 

anatomy (anat'omi) n. [Gk. ana, up ; 
tome, cutting.] The science that 
treats of the structure of plants and 
of animals ; the structure of a plant 
or of an animal. 

anatriaene (an'atrl'en) n. [Gk. ana, 
up ; triaina, a trident.] A triaene 
with backwardly directed cladi or 
branches (zool.}. 

anatropal (anat'ropal), anatropous 
(anat'ropus) a. [Gk. ana, up ; 
trepein, to turn.] Inverted, appl. 
ovules with the hilum and micro- 
pyle close together and the chalaza 
at the other end (bot.). 

anaxial (anak'sial) a. [Gk. a, with- 
out; axis, axis.] Having no distinct 
axis (biol.}. 

anchor (ang'kor) n. [L. ancora, 
anchor.] The anchor - shaped 
spicule found in the skin of Holo- 
thurians (zool.}. 

anchylosis (ang'kilo'sis) n. [Gk. 
angkylosis, stiffness.] The union 
of two or more bones or hard parts 
to form one part, e.g. of bone to 
bone, or tooth to bone (zool.}. 

anconeal (angko'neal) a. [L. ancon, 
elbow.] Pert, the elbow (anat.}. 

anconeus (ang'kone'us) n. [L. ancon, 
elbow.] Small extensor muscle 
situated over the elbow (anat.}. 

androconia (an'droko'nia) n. plu. 
[Gk. aner, man ; konia, dust.] 
Modified wing-scales producing a 
sexually attractive scent in certain 
butterflies (zool.}. 

androdioecious (an'drodle'shus) a. 
[Gk. aner, man ; dis, two ; oikos, 
house.] Having perfect male flowers 
on different plants (bot.). 

androecium (andre'shuim) n. [Gk. 
aner, man ; oikos, house.] The 
male reproducing organs of a 
plant ; the stamens taken col- 
lectively (bot.}. 

androgonidia (an'drogomd'ia) n. plu. 
[Gk. aner, man ; gonos, offspring.] 
Male sexual elements formed after 
repeated divisions of partheno- 
gonidia of volvox (sool.}. 

androgynal (androj'Inal), a. [Gk. 
aner, man ; gyne, woman.] Her- 
maphrodite; bearing bothstaminate 
and pistillate flowers in the same 
bunch (bot.}. 

androgynary (andrqj'inari) a. Having 
flowers with stamens and pistils 
developed into petals (bot.}. 

androgynism (andrqj'imzm) n. [Gk. 
aner, man ; gyne, woman.] The 
condition of bearing both stamens 
and pistils ; hermaphroditism (bot.}. 

androgynous (androj'inus), andro- 

androphore (an'drofor) n. [Gk. aner, 
man ; pherein, to carry.] Stalk 
supporting the stamens (bot.} ; the 
stalk carrying the male gonophores 
in the Siphonophora (zool.}. 

androphyll (an'drofil) n. [Gk. aner, 
man ; phyllon, leaf.] The leaf 




bearing the microspores ; the 
microsphorophyll (bot.). 
androsporangium (an'drosporan'jmm) 
n. [Gk. aner, man ; scores, seed ; 
anggeion, box.] A sporangium con- 
taining the androspores (hot.}. 
androspore (an'drospor') n. [Gk. 
aner, man ; sporos, seed.] An 
asexual zoospore which gives rise 
to a small male dwarf plant 

anemophily (an'gmof'ili) n. [Gk. 
anemos, wind ; philein, to love.] 
Plant-fertilization by the agency 
of wind (bot.). 

anemotropism (an'emot'ropizm) n. 
[Gk. anemos, wind ; trepein, to 
turn.] Orientation of the body 
with regard to wind (zool.). 

anenterous (anen'terus) a. [Gk. a, 
without ; enteron, gut.] Having 
no alimentary tract (zoo/.). 

anfractuose (anfrak'tuos) a. [L. an- 
fractus, a bending.] Wavy, sinuous 

angienchyma (an'jJeng'kTma) n. [Gk. 
anggeion, vessel ; engchein, to pour.] 
Vascular tissue (bot.). 

angioblast (an'jioblast) n. [Gk. 
anggeion, vessel ; blastos, bud.] 
One of the cells from which the 
lining of the blood-vessels is derived 

angiocarpous (an'jiokar'pus) a. [Gk. 
anggeion, vessel ; karpos, fruit.] 
Having the fruit enclosed in a 
cavity (bot.}. 

angiology (an'jlol'ojl) n. \G\a.anggeion, 
vessel ; logos, discourse.] The ana- 
tomy of the circulatory and lym- 
phatic systems (anat.). 

angiospermous (an'jiosper'mus) a. 

Sik. anggeion, vessel; sperma, seed.] 
having seeds in a closed case, the 
ovary (oof.). 

angiosporous (an'jfospo'rus) a. [Gk. 
anggeion, vessel ; sporos, seed.] 
Having spores contained in a theca 
or spore capsule (bot.}. 

angiostomatous (an'jiostom'atus) a. 
[Gk. anggeion, vessel ; stoma, 
mouth.] Narrow - mouthed, appl. 
a certain order of Molluscs, and 
to a sub-order of snakes with non- 
distensible mouths (zool.). 

angular (ang'gular) . [L. angulus, 
corner.] One of the membrane 

bones of the lower jaw in most 
vertebrates (zool.}. 

angulo-splenial (ang'gulosple'nial) . 
[L. angulus, corner ; splenium, a 
patch.] The bone in Amphibia 
forming most of the lower and inner 
part of the mandible (zool.). 

angustifoliate (anggus'tifo'llat) a. 
[L. angustus, narrow ; folium, a 
leaf.] With narrow leaves (bot.}. 

angustirostrate (anggus'tlros'trat) a. 
[L. angustus, narrow ; rostrum, a 
beak.] With narrow beaks or 
snouts (zool.). 

animal pole, in many ova the yolk 
is more or less aggregated at one 
pole, and as a result the segmenta- 
tion at that pole is retarded ; at the 
other pole, which is called the 
animal pole, the segmentation is 
more rapid and usually results in 
some form of overgrowth on the 
lower, retarded, or vegetable pole 

anion (anl'on) n. [Gk. ana, up ; ion, 
going.] A negatively-charged par- 
ticle or ion which moves up towards 
the anode or positive pole (fihys.). 

anisocarpous (anisokar'pus) a. [Gk. 
a, not ; isos, equal ; karpos, fruit.] 
Having the number of carpels less 
than that of the other floral whorls 

anisocercal (amsoser'kal} a. [Gk. a, 
not ; isos, equal ; kerkos, tail.] 
With lobes of the tail-fin unequal 

anisohela (amsoke'la) n. [Gk. a, 
not ; isos, equal ; chele, claw.] A 
chela with the two parts unequally 
developed (zool.). 

anisodactylous (anTsodak'tTlus) a. 
[Gk. a, not ; isos, equal ; daktylos, 
finger.] Having unequal toes, three 
toes forward, one backward ; refers 
to an old classification of birds 

anisogamous (anisog'amus) a. [Gk. 
a, not ; isos, equal ; gamos, mar- 
riage.] Appl. a conjugation in 
which the gametes or conjugating 
bodies are differentiated in some 
manner (biol.). 

anisogamy, conjugation between 
sharply differentiated gametes. 

anisognathous (an'fsogna'thus, an'- 
isog'nathtis) a. [Gk. a, not ; isos, 




equal ; gnathos, jaw.] Having the 
teeth in the upper and lower jaws 
unlike (sool.}. 

anisomerous (amsom'erus) a. [Gk. 
a, not ; t'sos, equal ; meros, part.] 
Having unequal numbers of parts 
in the floral whorls (hot.). 

anisopleural (anisoploo'ral) a. [Gk. 
a, not ; tsos, equal ; pleura, side.] 
Unsymmetrical bilaterally. 

anisopogonous (anisopog'onus) a. 
[Gk. a, not ; tsos, equal ; pogon, 
beard.] Unequally webbed with 
reference to feathers (zool.). 

anisopterous (anisop'tgrus) a. [Gk. 
a, not ; tsos, equal ; pteron, wing.] 
Unequally winged ; appl. seeds 

anisospore (anisospor') n. [Gk. a, 
not ; tsos, equal ; sporos, seed.] 
A dimorphic spore, the sexes 
differing in size (hot.}. 

anisostemonous (anisostgm'onus) a. 
[Gk. a, not ; t'sos, equal ; stemon, a 
spun thread.] Having the number 
of stamens unequal to the number 
of parts in the other floral whorls 

anisotropic (anisotrop'ik) a. [Gk. a, 
not ; tsos, equal ; trepein, to turn.] 
Appl. eggs with predetermined axis 
or axes (emb.). 

ankylosis, see anchylosis. 

anlage (anla'ge) n. [Ger. anliegen, 
to lie on.] The first accumulation 
of cells in a developing embryo 
recognizable as the commencement 
of a structure, organ, or part (smb.). 

annectent (aneVtSnt) a. [L. annectere, 
to bind together.] Linking, appl. 
intermediate species or genera 

annelid (an'Slid) a. [L. annulus, ring ; 
Gk. eidos, resemblance.] Con- 
structed of ring-like segments, as 
one of the ringed worms (zool.). 

annotinus (annot'iniis) n. [L. annus, 
year.] A year old (bot., zool.). 

annual (an'ual) a. n. [L. annus, year.] 
Appl. structures or features that are 
marked off or completed yearly ; 
living for a year only (pot.). 

annual ring, one of the rings seen 
in sections of dicotyledons indicat- 
ing the secondary growth of a year 
annular (an'ular) a. [L. annulus, 

ring.] Appl. certain fibrous bands 
or fascia in connection with the 
wrist and ankle, etc. (anat.) ; appl. 
certain vessels in xylem owing to 
the ring-like thickenings in their 
interior (bot.}. 

annulate (an'ulat) a. [L. annulus, 
ring.] Composed of ring-like seg- 
ments ; having the colour arranged 
in ring-like bands or annul!, as in 
earthworm or leech (zool.). 
annul! (an'ull) plu. of annulus. 
annulus (an'ulus) n. [L. annulus, 
ring.] Any of the ring-like struc- 
tures (anat.) ; the special ring in the 
fern sporangium, by the action of 
which the sporangium bursts ; the 
remains of the veil in mushrooms ; 
the ring of cells in the moss capsule 
whose rupture causes the opening 
of the capsule (bot.) ; a ring of an 
Annelid (zool.). 

anoestrum (ane'strum) n. [Gk. an, 
not ; oistros, gad-fly.] The non- 
breeding period ; the period of 
absence of sexual desire (biol.). 
anomaly (anom'all) n. [Gk. a, not ; 
homalos, even.] Any departure from 
the type characteristics (biol.). 
anomophyllous (an'omof'flus) a. [Gk. 
anomalos, uneven ; phyllon, leaf.] 
With irregularly placed leaves 

anorganology (an'organol'DJl) ;/. [Gk. 
a, not ; organon, instrument ; logos, 
discourse.] The study of non-living 
things (biol.}. 

anosmatic (anosmat'lk) a. [Gk. a, 
without ; osme, smell.] Having no 
sense of smell (phys.). 
antambulacral (ant'ambula'kral) a. 
[Gk. anti, against ; L. ambulare, to 
walk.] Not situated on the ambu- 
lacral area (zool.). 

antebrachium (an'tgbra'kTum) n. [L. 
ante, before ; brachium, arm.] The 
fore-arm, or corresponding portion 
of the fore-limb (zool.). 
antecubital (an'tgku'bital) a. [L. ante, 
before ; cubitum, elbow.] Anterior 
to the elbow (zool.). 
antedorsal (an'teclor'sal) a. [L. ante, 
before ; dorsum, back.] Situated 
in front of the dorsal fin in fishes 

antemarginal (an'temar'jinal) a. [L. 
ante, before ; inargo, an edge.] 




Appl. sori of ferns when they lie 
within the margin of the frond (dot.), 

antenna (anten'a) n. [L. antenna, a 
sail-yard.] A jointed feeler on the 
head of an insect or crustacean 

antennary (anten'arf) a. [L. antenna, 
a sail-yard.] Like or pert, or situ- 
ated near an antenna (zool.). 

antennule (anten'ul) . [L. dim. from 
antenna] A small antenna or feeler, 
specifically the first pair of antennae 
in Crustacea (zoo/,). 

anteposition (an'tSpdzTsh'un) n. [L. 
ante, before ; ponere, to place.] 
Superposition of whorls in a flower 
typically alternating (dot.). 

anterior (ante'rior) a. [L. anterior, 
former.] Nearer the head end 
(zool., anat.) ; ventral in human 
anatomy ; facing outwards from 
the axis (dot.). 

anthela (anthe'la) n. [Gk. anthein, to 
bloom.] The cymose inflorescence 
of the rush-family (hot.). 

anther (an'ther) n. [Gk. anthos, 
flower.] The part of the stamen 
which contains the pollen (dot.). 

antheridiophore (antherld'iofor) n. 
[Gk. anthos, flower ; idion, dim. ; 
pherein, to bear.] A gametophore 
bearing antheridia (dot.). 

antheridium (antherTd'ium) n. [Gk. 
anthos, flower ; idion, diml\ An 
organ or receptacle in which male 
sexual cells are produced (dot.). 

antherozoids (an'thSrozo'Idz) n. plu. 
[Gk. anthos, flower ; zoon, animal.] 
Male sexual cells in antheridia 

antherozooids (an'thgrozo'oidz) n.plu. 
[Gk. anthos, flower ; zoon, animal ; 
eidos, resemblance.]. Antherozoids. 

anthocarpous (an'thokar'pus) a. [Gk. 
anthos, flower ; karpos, fruit.] Appl. 
multiple fruits such as the straw- 
berry (dot.). 

anthocaulis (an'thokol'is) n. [Gk. 
anthos, flower ; L. caulis, stem.] 
The pedicle of a late trophozooid 
stage of Madrepore development 

anthocodia (an'thoko'dla) n. [Gk. 
anthos, flower ; kodeia, head.] The 
distal portion of an alcyonarian 
zooid bearing mouth and tentacles 

anthocyanin (an'thosi'anfti) n. [Gk. 
anthos, flower ; kyanos, dark blue.] 
Blue or violet colouring matter in 
flowers (dot.). 

anthocyathus (an'thosl'athus) n. [Gk. 
anthos, flower ; kyathos, cup.] The 
discoid crown of the trophozooid 
stage in Madrepore development 

anthodium (antho'dium) n. [Gk. 
anthos, flower ; eidos, resemblance.] 
The capitulum or head of flowers 
of a composite plant (dot). 

anthogenesis (an'thoje'n'e'sis) n. [Gk. 
anthos, flower ; gignesthai, to pro- 
duce.] In certain aphids the pro- 
duction of both malesand females by 
asexual forms (zool.). 

anthophilous (anthof'ilus) a. [Gk. 
anthos, flower ; philein, to love.] 
Fond of flowers ; appl. certain in- 
sects either living among or feeding 
on flowers (zool.). 

anthophore (an'thdfor) n. [Gk. anthos, 
flower ; pherein, to bear.] Elonga- 
tion of the thalamus between calyx 
and corolla (dot.). 

anthotaxis (an'thotak'sis) n. [Gk. 
anthos, flower ; taxis, arrangement.] 
The arrangement of flowers on an 
axis (dot.). 

anthoxanthine (an'thozan'thm) n. 
[Gk. anthos, flower; xanthos, yellow.] 
Yellow colouring pigment of flowers 

anthropogenesis (an'thropojgn'gsis) n. 
[Gk. anthropos, man ; genesis, de- 
scent, origin.] Theory of the de- 
scent of man. 

anthropoid (an'thropoid) a. [Gk. 
anthropos, man ; eidos, resem- 
blance.] Resembling man ; appl. 
Simian apes (zool.). 

anthropology (an'thropol'qji) n. [Gk. 
anthropos, man ; logos, discourse.] 
The natural history of man. 

anthropomorphous (an'thropomor'fus) 
a. [Gk. anthropos, man ; morphe, 
shape.] Resembling man. 

antiae (an'tle, an'tla) n. plu. [L. 
antiae, forelock.] Feathers at the 
base of the bill-ridge of some birds 

antibody (an'tibod'l) n. [Gk. anti, 
against ; A.S. bodig, body.] A 
substance formed in the blood 
which antagonizes toxins (phys.). 




antibrachlal (an'tlbra'kial) a. [Gk. 
anti, against ; L. brachium, arm.] 
Pert, forearm; appl. fascia, muscles, 
nerves (anat.). 

antibrachiuni (antibra'kTum), ante- 

anticlinal (an'tlkll'nal) a. [Gk. anti, 
against ; klinein, to bend.] Appl. 
line of division of cells at right 
angles to the apex (bot.) ; in quad- 
rupeds, appl. one of the lower 
thoracic vertebrae with upright 
spine towards which those on 
either side incline (zool.). 

anticoagulin (an'tlkoag'tilin) n. [Gk. 
anti, against ; L. cogere, to drive 
together.] A substance which 
prevents the coagulation of drawn 
blood, as hirudin (phys.). 

anticubital, antecubital. 

antidromy (antid'rom!) n. [Gk. anti, 
against ; dromos, running.] Condi- 
tion of spiral phyllotaxy with 
genetic spiral changing direction 
after each cycle (bot.). 

antigen (an'tljen) n. [Gk. anti, 
against; genos, birth.] Appl. sub- 
stances which, when injected into 
an animal, cause a series of physio- 
logico-chemical changes resulting 
in the formation of antibodies in 
the blood (phys.). 

antlhellac (an'tihe'liks) n. [Gk. anti, 
against ; helix, a convolution.] 
The curved prominence in front 
of the helix of the ear (anat.). 

antimeres (an'timerz) n. plu. [Gk. 
anti, against ; meros, part.] A 
series of equal radial parts of the 
body of a radially symmetrical 
animal (zool.). 

antipetalous (an'tipeYalus) a. [Gk. 
anti, against, opposite ; petalon, 
petal.] With stamens in front of 
petals (dot.). 

antipodal (antip'odal) a. [Gk. anti, 
against ; pous, foot.] Appl. group 
of three cells at chalazal end of 
embryo sac (bot.) ; appl. cone of 
astral rays opposite spindle fibres 

antiseptic (an'ttsep'tik) a. [Gk. anti, 
against ; sepsis, putrefaction.] A 
substance which destroys harmful 
micro-organisms, one of the 
functions of gastric juice (phys.). 

antispadix (an'tispa'dlks) . [Gk. 

anti, against ; spadix, a palm 
branch.] A group of four modified 
tentacles in internal lateral lobes 
of Nautilus (zool.). 

antisquama (an'tiskwa'ma) n. [Gk. 
anti, against ; L. squama, scale.] 
A basal lobe next the squama of 
insect wing ; the squama alaris or 
antitegula (zool.). 

antitegula (an'titeg'ula) n. [Gk. anti, 
against ; L. tegula, tile.] Smaller 
lobe, nearer the base of wing, than 
alula (zool.). 

antithrombin (an'tithrom'bm) n. [Gk. 
anti, against ; thrombos, clot.] A 
substance formed in the liver 
which prevents clotting of the 
blood (phys.). 

antitoxin (an'titok'sin) n. [Gk. anti, 
against; toxikon, poison for arrows.] 
A substance which develops as a 
result of, and subsequently neutral- 
izes, the injection of a specific 
poison introduced into the animal 
body (phys.). 

antitragus (an'titrag'us) n. [Gk. anti, 
against; tragos, he -goat.] A 
prominence opposite the tragus 
of the ear (ana/.). 

antitrochanter (an'tltrokan'te'r) n. 
[Gk. anti, against ; trochanter, a 
runner.] An articular surface on 
the ilium in birds against which 
the trochanter of the femur plays 

antitrppal (antit'ropal) a. [Gk. anti, 
against ; trepein, to turn.] In- 
verted ; appl. embryos with radicle 
directed away from the hilum (bot.). 

antitropous, ant i t ropal. 

antlia (ant'lia) n. [L. antlia, pump.] 
The spiral suctorial proboscis of 
the Lepidoptera (zool.). 

antorbital (ant6r'bital) n. [L. ante, 
before ; orbs, circle.] Situated in 
front of the orbit (zool.). 

antrum (an'trum) n. [L. antrum, 
cavity.] A cavity or sinus ; appl. 
maxillary sinus, and cavity of the 
pylorus (anat.). 

anurous (anu'rus) a. [Gk. a, without ; 
oura, tail.] Tailless. 

anus (a'nus) n. [L. anus, anus.] The 
posterior opening of the alimentary 
canal (anat.). 

aorta (aorta) n. [Gk. aorte, the great 
artery.] The great trunk artery- 




which carries pure blood from the 
heait for distribution to various 
parts of the body through arteries 
and their branches (anat.). 

aortic (aor'tik) a. [Gk. aorte, the 
great artery.] Pert, the aorta ; appl. 
arch, hiatus, isthmus, septum, etc. 
(anat.), regurgitation (phys.). 

apatetic (ap'atet'ik) a. [Gk. apatet- 
ikos, fallacious.] Appl. misleading 
coloration (zool.). 

aperispermic (apeYisper'mik) a. [Gk. 
a, without ; peri, around ; sperma, 
seed.] Appl. seeds without nutritive 
tissue (dot.}. 

apetalous (apet'alib) a. [Gk. a, with- 
out ; pe talon, petal.] Having no 
petals (bot.). 

apex (a'pfiks) n. [L. apex, summit.] 
The tip or summit, as of lungs, 
heart, etc. (anat.). 

aphanipterous (af'anlp'terus) a. [Gk. 
aphanes, unseen ; pteron, wing.] 
Apparently without wings (zool.}. 

apheliotropism (af'ellot'ropizm) n. 
[Gk. apo, away; helios, sun; trepein, 
to turn.] Tendency to turn away 
from light (biol.). 

aphodal (af 'odal) a. [Gk. apo, away ; 
hodos, way or path.] Appl. a type 
of canal system in sponges (zool.}. 

aphodus (af'ddus) n. [Gk. apo, away ; 
hodos, path.] The short tube lead- 
ing from the flagellate chamber to 
the excurrent canal in one of the 
types of canal systems in sponges 

aphyllous Oftftfs) a. [Gk. a, with- 
out ; phyllon, leaf.] Without foliage 
leaves (bot.}. 

aphylly (afil'l) . [Gk. a, without ; 
phyllon, leaf.] Suppression or 
absence of leaves (bot.}. 

apical (ap'ikal) a. [L. apex, summit.] 
At the tip or summit, appl. cell at 
tip of a growing point (bot.} 
appl. aboral plates of Echinoderms 

apiculate (aptk'ulat) a. [L. apex, 
summit.] Forming abruptly to a 
small tip, as a leaf (bot.}. 

apilary (apilarl) a. [Gk. a, not ; 
pilos, felt cap.] Having the upper 
lip wanting or suppressed in the 
corolla (bot.}. 

aplacental (ap'lasen'tal) a. [L. a, 
not ; placenta, flat cake.] Not 

developing a placenta, as in Mono- 
tremes (zool.). 

aplanogamete (aplan'ogamet') . 
[Gk. a, not ; pianos, wandering ; 
gamete, wife.] A non-motile con- 
jugating germ cell in various plants 
and animals (biol.). 

aplanospore (aplan'ospor) n. [Gk. a, 
without ; pianos, wandering ; sporos, 
seed.] A non-motile resting spore 
of Algae for tiding over unfavourable 
circumstances (bot.). 

aploperistomatous (ap'loper'lstom'- 
atus) a. [Gk. aploos, single ; peri, 
around ; stoma, mouth.] Having a 
peristome with one row of teeth, as 
mosses (bot.). 

aplostemonous (ap'lostem'onus) a. 
[Gk. aploos, single ; stemon, a spun 
thread.] Having a single row of 
stamens (bot.). 

apneustic (apnu'stik) a. [Gk. a, 
without ; pneustos, breath.] With 
closed tracheal system ; appl. aqua- 
tic larvae of certain insects (zool.). 

apocarpous (ap'okar'pus) a. [Gk. 
apo, away ; karpos, fruit.] Having 
separate or partially united carpels 

apocyte (ap'osit) n. [Gk. apo, away ; 
kytos, hollow.] A multinucleate 
cell, a plurinucleate mass of 
protoplasm (cyt.). 

apodal (ap'odal) a. [Gk. a, without ; 
pous, foot.] Having no feet (zool.). 

apodema (ap'ode'ma) n. [Gk. apo, 
away ; demas, body.] An internal 
projection usually of thoracic seg- 
ments, for muscle attachments, 
found in Arthropods (zool.). 

apodous (ap'odus), apodal. 

apogamy (apog'aml) n. [Gk. apo, 
away ; gamos, marriage.] Develop- 
ment without the intervention of 
sexual organs (bot.). 

apogeotropic (ap'oje'otrSp'lk) a. [Gk. 
apo, away ; gaia, earth ; trepein, to 
turn.] Having the property of turn- 
ing away from the earth (bot.). 

apogeotropism (ap'qjeot'ropizm) n. 
[Gk. apo, away ; gtiia, earth ; tre- 
Pein, to turn.] Tendency to act 
apparently contrary to law of 
gravity this is, to turn away from 
the earth (biol.). 

aponeurosis (ap'b'nuro'sis) n. [Gk. 
apo, from ; neuron, sinew ] The 




flattened tendons of certain muscles 

apophyllous (ap'ofil'us) a. [Gk. apo, 
away ; phyllon, leaf.] Appl. the 
parts of a single perianth whorl 
when they are free leaves (bot.). 

apophysis (apof'isis) n. [Gk. apo, 
away ; phyein, to grow.] Process 
from a bone, usually for muscle 
attachment (anat.) ; a swelling at 
the base of the capsule in some 
mosses ; appl. small protuberance 
at apex of an ovuliferous scale in 
female cone of pine (bot.). 

apoplasmodial (ap'oplasmo'dial) a. 
[Gk. apo, away ; plasma, something 
moulded.] Not forming a typical 
plasmodium (zool.). 

apopyle (ap'opil) n. [Gk. apo, away ; 
pyle, gate.] The exhalent pore of 
a sponge (zool.). 

aposematic (ap'osemat'ik) a. [Gk. 
apo, away ; sema, signal.] Appl. 
warning colours which serve to 
frighten away enemies (zool.). 

aposporogony (ap'osporog'onT) n. 
[Gk. apo, away ; sporos, seed ; 
gonos, birth.] The absence of 
sporogony (zool.). 

apospory (apos'pori) n. [Gk. apo, 
away ; sporos, seed.] The produc- 
tion of prothalli without the inter- 
vention of spore-formation in certain 
plants (bot.). 

apostasis (apos'tasis) n. [Gk. apo, 
away ; stasis, standing/] Term 
appl. condition of abnormal growth 
of axis which thereby causes a 
separation of the perianth whorls 
from one another (bot.). 

apostrophe (apos'trofe) n. [Gk. apo, 
away ; trepein, to turn.] Arrange- 
ment of chloroplasts along the 
lateral walls of cells of leaves 

apothecium (ap'othe'siiim, -shium) n. 
[Gk. apo, away ; theke, cup.] The 
ascocarp of Lichens (bot.). 

apotropous (apot'ropus) a. [Gk. apo, 
away ; trepein, to turn.] Anatropal 
and with ventrally-situated raphe 

appendage (apen'daj) n. [L. ad, to ; 
pendere, to hang.] An organ or 
part attached to a trunk, as a limb 

appendicula (up'endik'ular) a. [L. 

ad, to ; pendere, to hang.] Pert. 
appendages; appl. skeleton of limbs 
as opposed to skeleton of trunk 

appendiculate (ap'endlk'ulat) a. [L. 
ad, to ; pendere, to hang.] Having 
a small appendage, as a stamen or 
filament (bot.). 

appendix (apen'diks) n. [L. ad, to ; 
pendere, to hang.] An outgrowth, 
especially the vermiform appendix 

applanate (ap'lanat) a. [L. ad, to ; 
planatus, flattened.] Flattened 
out (bot.). 

apposition (ap'ozish'un) n. [L. ad, to ; 
ponere, to place.] The formation 
of successive layers in the growth 
of a cell wall ; cf. intussusception 

aproterodont (ap'roter'b'dont, apro'- 
terodont) a. [Gk. a, without ; pro- 
teros, first ; odous, tooth.] Hav- 
ing no teeth on the pre-maxillae 

apteria (apte'ria) n. plu. [Gk. a, with- 
out; pteron, wing.] Naked or down- 
covered surfaces between the ptery- 
lae or feather-tracts (zool.). 
apterous (ap'terus) a. [Gk. a, with- 
out ; pteron, wing.J Wingless 
(zool.) ; having no wing-like ex- 
pansions on the stems or petioles 

apterygial (ap'terij'ial) a. [Gk. a, 
without ; pteron, wing.] Wingless ; 
without fins (zool.). 

apterygotous (ap'terigo'tus) a. [Gk. 
a, without ; pterygion, dim. of pteron, 
wing.] Resembling or pert, the 
primitive wingless insects or Aptery- 
gota (zool.). 

aptychus (ap'tikiis) n. [Gk. a, with- 
out ; ptyche, fold.] A horny or 
calcareous structure, possibly an 
operculum, of Ammonites (zool.). 
aquatic (akwat'ik, -wot-) a. [L. aqua, 
water.] Pert, water ; living in or 
frequenting water (bot., zool.). 
aqueduct (ak'wedukt) n. [L. aqua, 
water ; ducere, to lead.] A channel 
or passage as that of cochlea, and 
of vestibule of ear (anat.). 
aqueous (a'kweus) a. [L. aqua, water.] 
Watery, appl. fluid occupying the 
space between the lens and the 
cornea of the eye (anat.) ; appl. 




tissue consisting of thin -walled 
watery parenchymatous cells (bot.}. 

arachnid (arak'md) a. [Gk. arachne, 
spider.] Spider-like, pert, spiders 

arachnidium (araknid'ium) n. [Gk. 
arachne, spider.] The spinning 
apparatus of a spider, including 
spinning-glands and spinnerets 

arachnoid (arak'noid) a. [Gk. arach- 
ne, spider ; eidos, form.] Like a 
cobweb ; consisting of fine en- 
tangled hairs resembling a cobweb 
(bot.} ; appl. a thin membrane of 
the central nervous system, com- 
posed of delicate connective tissue 
with an endothelial covering on its 
free surfaces and lying between the 
dura and the pia mater (ana/.} ; 
pert, or resembling a spider (zool.}. 

arborescent (ar'bore's'e'nt) a. [L. ar- 
borescens, growing like a tree.] 
Branched like a tree (bot.}. 

arboroid (ar'boroid) a. [L. arbor, 
tree ; Gk. eidos, like.] Tree-like, 
designating general structure of a 
protozoan colony (zool.}. 

arbor vitae (ar'bor vl'te, ve'ta) n. [L. 
arbor, tree ; -vita, life.] The tree 
of life, appl. arborescent appear- 

- ance of the cerebellum in vertical 
. section (anat.}. 

arbutean (arbu'tean) a. [L. arbutus, 
strawberry tree.] Of or pert, the 
strawberry tree (bot.}. 

arcade (arkad') n. [L. arcus, a bow.] 
An arched channel or passage ; a 
bony arch, as supra- and infra- 
temporal arches in the skull (anat.}. 

archaeocytes (ar'keoslts) n.plu. [Gk. 
archaios, ancient ; kytos, hollow.] 
Cells arising from undifferentiated 
blastomeres and ultimately giving 
rise to germ-cells and gametes 

archaeostomatous (ar'keosto'm'atus) a. 
[Gk. archaios, primitive ; stoma, 
mouth.] Having the blastopore per- 
sistent and form ing the mouth (zool.}. 

arch-centra (ark'-seVtra) n. plu. [Gk. 
archi, beginning, first ; L. centrum, 
centre.] Centra formed by fusion 
of basal growths of primary arcualia 
external to chordal sheath ; cf. 
chordacentra (zool.}. 

archebiosis (ar'keblo'sls) n. [Gk. 

arche, beginning ; bios, life.] The 
origin of life (biol.}. 

archegoniophore (ar'kego'niofor) n. 
[Gk. arche, beginning ; gonos, off- 
spring ; pkerein, to bear.] Branches 
of mosses bearing archegonia (bot.}. 

archegonium (ar'kego'mum) n. [Gk. 
arche, beginning ; gonos, offspring.] 
A female organ in which the 
oospheres are formed, and in which 
the young plant begins its develop- 
ment (bot.}. 

archenteron (arkgn'tgron) n. [Gk. 
arche, beginning ; enteron, gut.] 
The cavity of the gastrula which 
forms the primitive gut of the 
embryo (emb.}. 

archespore (ar'kespor) n. [Gk. arche, 
beginning ; sporos, seed.] The 
tetrahedral or meristematic cell of 
a sporangium (bot.}. 

archiamphiaster (ar'kTam'fTas'te'r) n. 
[Gk. archi, first ; amphi, on both 
sides ; aster, star.] The amphiaster 
forming the first or second polar 
body in cell maturation (cyt.}. 

archiblast (ar'kiblast) n. [Gk. archi, 
first ; blastos, bud.] Egg proto- 

archiblastic (ar'kiblas'tik) a. [Gk. 
archi, first ; blastos, bud.] Having 
total and equal segmentation (cyt.}. 

archiblastula (ar'kiblas'tula) n. [Gk. 
archi, first ; blastos, bud.] Typical 
hollow ball of cells derived from an 
egg with total and equal segmenta- 
tion (cyt.}. 

archicarp (ar'kikarp) n. [Gk. archi, 
first ; karpos, fruit.] The spirally 
coiled region of the thallus of 
certain fungi (bot.}. 

archicerebrum (ar'kise'r'e'brum) n. 
[Gk. archi, first ; L. cerebrum, brain.] 
The primitive brain, as the supra- 
oesophageal ganglia of higher 
Invertebrates (zool.}. 

archichlamydeous (ir'kiklamid'eus) a. 
[Gk. archi, first ; chlamys, cloak.] 
Having no petals, or having petals 
entirely separate from one another 

archicoel (i/kisel) n. [Gk. archi, 
first ; koilos, hollow.] The primary 
body- cavity or space between v the 
alimentary canal and ectoderm in 
development of various groups of 
animals (zoo/.}. 




archigony (arkig'onl) n. [Gk. archi, 
first ; gonos, offspring.] The first 
origin of life by spontaneous genera- 
tion (bio!.}. 

archinephric (ar'kmef'rik) a. [Gk. 
archi, first ; nephros, kidney.] Appl. 
the duct into which the pronephric 
tubules open (emb.}. 

archinephros (ar'kinef'ros) n. [Gk. 
archi, first ; nephros, kidney.] The 
primitive kidney (emb.}. 

archipallium (ar'kTpal'ium) n. [Gk. 
archi, first ; L. pallium, a mantle.] 
The olfactory region of the cerebral 
hemispheres (phys.}. 

archipterygium (ar'kipterij'ium) n. 
[Gk. archi, first ; pterygion, little 
wing.] Type of fin in which the 
skeleton consists of an elongated 
segmented central axis and two 
rows of jointed rays (zool.}. 

architype (ar'kitip) n. [Gk. archi, 
first ; typos, type.] An original type 
from which others may be derived 

archoplasm (ar'koplazm) n. [Gk. 
archon, ruler ; plasma, something 
moulded.] The substance con- 
stituting the attraction sphere, 
astral rays, and spindle-fibres 

arclcentrous (ar'kisen'trus) a. [L. 
arcus, bow ; centrum, centre.] 
Appl. vertebral columns in which 
the centra are mainly derived from 
the arch tissue (emb., anat.). 

arciferous (arsif'eYus) a. [L. arcus, 
bow ; ferre, to carry.] Appl. pec- 
toral arch of toads, etc., where the 
precoracoid and coracoid are widely 
separated and connected by a large 
arched epicoracoid (zool.}. 

arciform (ar'siform) a. [L. arcus, 
bow ; forma, shape.] Shaped like 
an arch or bow (zool.}. 

arcocentrous (ar'kb'sen'trus) a. [L. 
arcus, bow ; centrum, centre.] Appl. 
vertebral columns with inconspicu- 
ous chordal sheath and centra de- 
rived from arch tissue (zool.}. 

arcocentrum (ar'kosSn'trum) n. [L. 
arcus, bow ; centrum, centre.] A 
centrum formed from parts of neural 
and haemal arches (zool.}. 

arcualia (ar'kua'lia) n.plu. [L. arcus, 
bow.] Small cartilaginous pieces, 
dorsal and ventral, fused or free, on 

the vertebral column of fishes 

arcuate (ar'kuat) a. [L. arcus, bow.] 
Curved or shaped like a bow. 

ardellae (ardeTe) n. plu. [Gk. ardein, 
to sprinkle.] Small apothecia of 
certain lichens having the appear- 
ance of dust (bot.}. 

area (a'rea) n. [L. area, ground-space.] 
A surface, as area opaca, area 
vasculosa (smb.}. 

arenaceous (arSna'shus) a. [L. arena, 
sand.] Having the properties or 
appearance of sand ; sandy. 

areola (are'ola) n. [L. areola, dim. of 
area, space.] A small coloured 
circle round a nipple ; the part of 
the iris bordering the pupil of the 
eye (anat.} ; one of the small spaces 
or interstices of a special kind of 
tissue (zool.} ; the areas defined by 
cracks on the surface of lichens (bot.}. 

areolar (are'olar), areolate (are'olat) a. 
[L. areola, space.] Of or like an 
areola, having distinct spaces or 
interstices (bot.} ; areolar is appl. a 
kind of connective tissue with the 
fibres loosely attached (zool.}. 

argenteal (arjen'teal) a._ [L. argenteus, 
silvern.] Appl. layer of the eye 
containing calcic crystals (zvol.}. 

argenteous (arjen'teus) a. [L. argen- 
teus, silvern.] Like silver (bot.}. 

argent euin (arjgn'teum) n. [L. argen- 
tum, silver.] A dermal reflecting 
tissue layer of iridocytes without 
chromatophores in fishes (zool.}. 

aril (ar'il), arillus (aril'us) n. [F. 
arille, Sp. arillo, a small hoop.] 
An additional investment formed on 
a seed after fertilization (bot.}. 

arillode (ar'ilod) n. [F. arille, hoop ; 
Gk. eidos, like.] A false arillus 
arising from the micropyle as an 
expansion of the exostome (bot.}. 

arista (arls'ta) n. [L. arista, beard of 
an ear of corn.] Awn ; long-pointed 
process as in many grasses (bot.} ; 
a bristle borne by the antenna of 
many brachycerous Diptera (zool.}. 

Aristotle's lantern (Ar'istot'lz), the 
masticating apparatus of the sea- 
urchin (zool.}. 

armature (ar'matur) n. [L. arma, 
weapons.] Anything which serves 
to defend, as hairs, prickles, thorns 
(bot.} ; spines, stings, etc. (zool.}. 




arolium (an/Hum) n. [Gk. arole, pro- 
tection.] Pad between the claws 
on tarsus of Orthoptera (zool.). 

arrectores pilorum, bundles of non- 
striped muscular fibres associated 
with the hair follicles, on con- 
traction, they render the hair more 
erect (p/iys.). 

arrhenoplasm (arSn'oplazm) . [Gk. 
arrenos, male ; plasma, something 
moulded.] Male plasm, in reference 
to the theory that all protoplasm 
consists of arrhenoplasm and thely- 
plasm (diol.). 

arrhenotoky (argnot'oki) . [Gk. 
arrenos, male ; tokos, birth.] Pro- 
duction of males parthenogenetic- 
ally (zool.). 

arterial (arte'rial) a. [L. arteria, 
artery.] Pert, an artery, or the 
system of channels by which the 
blood issues to the body from the 
heart ; appL blood, duct, gland 

arterial sclerosis, hardening of the 
walls of the arteries, said to con- 
tribute to natural death (phys.). 

arteriole (arte'rlol) n. [L. arteriola, 
small artery.] A small or branch 
artery (anat.). 

artery (ar'te"r!) n. [L. arteria, artery.] 
A vessel which conveys blood from 
heart to body (anat.). 

arthritic (arthrit'ik) a. [Gk. arthron, 
joint.] Pert, or at joints (anat.). 

arthrobranchiae (aYthrobrang^kle, 
-kla) n. plu. [Gk. arthron, a joint ; 
drangchia, gills.] Joint-gills, arising 
at the junction of thoracic append- 
ages with trunkof Arthropods (zool.). 

arthrodia (arthro'dia) . [Gk. arthron, 
joint.] A joint admitting of only 
gliding movements (anat.). 

arthrodlal (arthro'dlal) a. [Gk. 
arthron, joint.] Appl. the articular 
membranes connecting thoracic 
appendages with trunk, as in 
Arthropods (zool.). 

arthromere (ar'thrb'mer) n. [Gk. 
arthron, joint ; meros, part.] An 
arthropod body-segment or somite 

arthropod (ar'thropod) a. [Gk. 
arthron, joint ; pous, foot.] Of or 
pert, the Arthropoda (zool.). 

arthropterous (arthr6p't6rus) a. [Gk. 
arthron, joint ; pteron, wing.] 

Having jointed fin-rays, as in fishes 

arthrospore (Arth'rospor) n. [Gk. 
arthron, joint ; sporos, seed.] A 
resting bacterial cell (hot.}. 

arthrosterigmata (ar'throste'rig'mata) 
n.plu. [Gk. arthron, joint; sterigma, 
a support] Jointed sterigmata (dot.'). 

arthrostracous (arthrSs'trakus) a. 
[Gk. arthron, joint ; ostrakon, shell.] 
Having a segmented shell (zool.). 

articular (artik'ula>) a. [L. articulus, 
joint] Pert, or situated at a joint 
or joints ; appl. cartilage, lamellae, 
surface, capsule, etc. (anat.}. 

articulated (artik'ulate'd) a. [L. arti- 
culus, joint.] Jointed ; separating 
easily at certain points (fe&jl 

articulation (irtikula'shun) n. [L. 
articulus, joint.] A joint, between 
bones or segments (zool.\ or seg- 
ments of a stem (dot.). 

artifact (ar'tlfakt) n. [L. ars, art; 
facere, to make.] Any appearance 
produced by a reagent or other 
artificial means (biol^). 

artiodactyl (ar'tiodaktil) a. [Gk. 
artios, equal ; daktylos, finger.] 
Having an even number of fingers 
or toes (sool.) 

arytenoid (arjrte'noid) a. [Gk. 
arytaina, a pitcher.] Pitcher-like, 
appl. two cartilages at the back of 
the larynx, also glands, swellings, 
etc. (anat.\ 

asci (as'I, as'kl, as'ke) n. plu. [Gk. 
askos, bladder.] Membranous spore- 
sacs of fungi within which the 
ascospores are formed (dot.}. 

ascidian (asld'Ian) a. [Gk. askidion, 
dim. of askos, bag.] Like an 
ascidian or sea-squirt (zool.). 

ascidium (asld'lum) n., ascidia (asTd'Ia) 
plu. [Gk. askidion, little bag.] 
Pitcher-leaves, as in Nepenthes 

ascigerous (aslj'grus) a. [Gk. askos, 
bag ; L. gerere, to bear.] Bearing 
asci, as certain hyphae in Fungi 

ascocarp (as'kokarp) n. [Gk. askos, 
bag ; karpos, fruit.] The protective 
covering investing the asci (dot.). 

ascogenous (ask8j'5nus) ^ a. [Gk. 
askos, bag ; gignesthai, to pro- 
duce.] Bearing asci (dot.). 

ascogonium (as'kogo'nTum) n. [Gk. 




askos, bag ; gignesthai, to produce.] 
A sac-like structure in which the 
reproductive bodies are formed 

ascospore (as'kospor) n. [Gk. askos, 
bag ; sporos, seed.] One of the 
spores contained in an ascus (bot.). 

ascus, sing, of asci, which see. 

asexual (aseVsual) a. [Gk. a, with- 
out ; L. sexus, sex.] Having no 
apparent sexual organs ; patheno- 
genetic or vegetative as appL repro- 
duction (btol.). 

aspect (as'pekt) n. [L. ad, to; 
spectare, to look.] Look, appear- 
ance, point of view (btol.). 

asperity (aspeViti) n. [L. asper, 
rough.] Roughness as on certain 
leaves (hot.}. 

aspidobranchiate (as'pidobrang'kiat) 
a. [Gk. aspis, shield ; brangchia, 
gills.] Pert, or resembling the 
Aspidobranchiata, a group of 
Gasteropods (zool.). 

asplanchnic (asplangk'nik) a. [Gk. 
a, without ; splangchna, viscera.] 
Without alimentary canal (zool.). 

asporous (asp5'rus) a. [Gk. a, with- 
out ; sporos, seed.] Having no 
spores (bot.). 

assimilation (asTm'ila'shun) n. [L. ad, 
to ; similis, like.] Conversion into 
protoplasm of ingested nutrient 
material (phys.). 

association (aso'sia'shun) . [L. ad, 
to ; socius, fellow.] Adherence of 
gregarines without fusion of nuclei 
(zool.} ; appl. fibres connecting 
white matter of interior of brain 
with cortex of convolutions (phys.). 

astely (Aste'H) n. [Gk. a, without ; 
stele, pillar.] Absence of a central 
cylinder or axis (hot.}. 

aster (as'tgr) n. [Gk. aster, a star.] 
The star-shaped achromatinic 
structure surrounding the centro- 
some during mitosis ; the star- 
shaped arrangement of the 
chromosomes during mitosis (cyt.). 

asterion (aste'rion) n. [Gk. aster, 
star.] The region of the postero- 
lateral fontaneTle where lambdoid, 
parieto - mastoid, and occipito- 
mastoid sutures meet (anat.). 

asteroid (as'tgroid) a. [Gk. aster, star ; 
eidos, resemblance.] Star-shaped ; 
pertaining to the star-fish (zoou). 

asterospondylous (as'tSrospon'dllus) 
a. [Gk. aster, star ; sphondylos, 
vertebra.] Having centrum with 
radiating calcified plates (zool.). 

astomatous (astom'atus) a. [Gk. a, 
without; stoma, mouth.] Not having 
a mouth (zool.) ; without epidermic 
pores or stomata (bot.). 

astomous (asto'mus) a. [Gk. a, with- 
out ; stoma, mouth.] Without a 
stomium or line of dehiscence ; 
bursting irregularly (bot.). 

astragalus (astrag'alus) n. [Gk. 
astragalos, an ankle bone.] The 
second largest tarsal bone in man 
(anat.); a tarsal bone in Vertebrates. 

astrocentre (as'trosSn'ter) n. [L. aster, 
star ; centrum, centre.] The centro- 
some (cyt.). 

astrosphere (as'trosfer) n. [Gk. aster, 
star ; sphaira, ball.] The central 
mass of the aster without the rays ; 
the aster exclusive of the centro- 
some ; the astral sphere (cyt.). 

asymmetrical (asimet'rikal) a. [Gk. 
a, without ; syn, with ; metron, 
measure.] Pert, want of sym- 
metry ; in the condition of having 
two sides unlike or disproportion- 
ate ; appl. structures or organs 
which cannot be divided into 
similar halves by any vertical axis 

asymmetry (asTm'gtri) n. [Gk. a, with- 
out ; syn, with; metron, measure.] 
Want of symmetry. 

atavism (at'avizm) n. [L. atavus, 
ancestor.] Reversion, the oc- 
currence of a characteristic of a 
remote ancestor not .observed in 
the more immediate ancestors 

atavistic (at'avls'tik) a. [L. atavus, 
ancestor.] Pert, marked by, or 
tending to atavism (btol.). 

athalamous (athal'amus) a. [Gk. a, 
without ; thalamos, inner room.] 
Wanting a thalamus (bot.). 

atlas (at'las) n. [Gk. atlas, a giant.] 
The first cervical vertebra articulat- 
ing with the skull (anat.). 

atokous (at'okus) a. [Gk. atokos, 
childless.] Without offspring. 

atoll (at'61, atol') n. [Mai. atoll.} A 
coral reef surrounding a body of 
water (zool.). 

atria! (a'triil) a. [L. atrium, a central 




room.] Pert, atrium ; appl. cavity, 
pore, canal, siphon, lobes (zool.). 

atriocoelomic (a'trloselom'ik) a. [L. 
atrium, central room ; Gk. koilos, 
hollow.] Connecting the atrium 
and the coelom ; appl. funnels, of 
uncertain function, in Cephalo- 
chorda (zool.). 

atriopore (a'triopor) n. [L. atrium, 
central room ; porus, channel.] 
The opening from the atrial cavity 
to the exterior in Cephalochorda 

atrioventricular (atriove'ntrik'ular) a. 
[L. atrium, chamber ; ventriculus, 
small cavity.] Pert, the atrioven- 
tricular structure in the heart ; appl. 
bundles, groove, openings (anat.). 

atrium (a'trium) n. [L. atrium, 
chamber.] The two anterior cavi- 
ties of the heart ; the tympanic 
cavity (anat.) ; a chamber surround- 
ing the pharynx in Tunicates and 
Cephalochordates (zoo!.). 

atrochal (at'rokal) a. [Gk. a, with- 
out ; trochos, wheel.] Without the 
preoral circlet of cilia ; appl. tro- 
chophore stage when the preoral 
circlet is absent and the surface 
is covered uniformly with cilia 

atrophy (at'rofi) n. [Gk. a, without ; 
trephein, to nourish.] Emaciation ; 
diminution in size and function of 
a part or organ (biol.). 

atropous (at'ropus) a. [Gk. a, with- 
out ; trepein, to turn.] Appl. ovule 
in proper position, i.e. not inverted 

atterminal (atteYmmal) a. [L. ad, 
to ; terminus, end.] Towards a 
terminal ; appl. current directed 
toward the thermal cross-section 

attraction (atrak'shun) n. [L. at- 
tractus, drawn to.] Any structure 
which apparently draws other 
things to it, as an attraction cone 

auditory (od'itorl) a. JX. audire, to 
hear.] Pert, the hearing apparatus, 
appl. organ, nucleus, ossicle, capsule, 
canal, meatus, nerve, tentacle, etc. 

Auerbach's plexus, a gangliated 
plexus of non-medullated nerve- 
fibres, found between the two layers 
of the muscular coat of the small 

intestine ; the plexus myentericus 

augmentor (ogme'n'tSr) a. [L. augere, 
to increase.] Appl. nerves rising 
from the sympathetic system and 
acting on the heart, with antago- 
nistic relation to the vagi ; ac- 
celerator (phys.). 

aulostomatous (ol'ostom'atus) a. [Gk. 
aulos, tube ; stoma, mouth.] Having 
a tubular mouth or snout (zool.). 

aural (6^1) a. [L. auris, ear.] Pert. 
ear or hearing. 

auricle (6r'lkl) n. [L. auricula, little 
ear.] The external ear ; any ear- 
like lobed appendage (zool.) ; the 
upper or anterior chamber on each 
side of the heart (anat.). 

auricula (orik'ula) n. [L. auricula, 
little ear.] An auricle. 

auricular (ortk'ular) a. [L. auricula, 
small ear.] Pert, an auricle ; appl. 
artery, nerve, tubercle, vein (anat.). 

auricularia (orik'ula'ria) n. [L. auri- 
cula, small ear.] A type of larva 
found among the Holothurians 

auriculars, n. plu., ear coverts of 

auriculate (orik'ulat) a. [L. auricula^ 
small ear.] Eared ; appl. leaf with 
expanded bases surrounding the 
stem ; appl. leaf with lobes separate 
from rest of blade ; hastate-auricled 

auriculo - ventricular (6rik'ulo-vn- 
trflc'ular) a. Pert, or connecting the 
auricle and ventricle of the heart ; 
appl. bundle, valve (anat.). 

aurophore (or'ofor) n. [L. auris, ear ; 
Gk. pherein, to bear.] An organ 
projecting from the base of pneu- 
matophore of certain Siphonophores 

autacoid (ot'akoid) n. [Gk. autos, 
self.] A term including both 
hormone and chalone (phys.). 

autoblast (ot'dblast) n. [Gk. autos, 
self; blastos, bud.] An inde- 
pendent micro-organism. 

autocatalysis (ot'okatal'isls) n. [Gk. 
autos, self ; kata, down ; lysis, a 
loosing.] The dissolution or re- 
action of a cell or substance due 
to the influence of a product or 
secretion of its own (phys.). 

autochthon (6tSk'th6n) n. [Gk. autos, 




self; chthon, the ground.] An 
indigenous species of plant or 
animal (bioL). 

autocyst (ot'osist) n. [Gk. autos, self; 
kystis, bladder.] A thick membrane 
formed by the Neosporidia separat- 
ing them from the host tissues (zoo/.). 

autodermalia (ot'odermal'ia) n. plu. 
[Gk. autos, self; derma, skin.] 
Dermal spicules with axial cross 
within the dermal membrane (zool.). 

autoecious (ote'shus) a. [Gk. autos, 
self; oikos, house.] Appl. rusts 
whose aecidium form inhabits the 
same host as the uredoform stage 

autogamy (otog'ami) n. [Gk. autos, 
self; gamos, marriage.] Self- 
fertilization (biol.). 

autogenesis (6t'6jen'e'sis) n. [Gk. 
autos, self; genesis, birth.] Spon- 
taneous generation (biol.). 

autogenetic (ot'qje'net'lk) a. [Gk. 
autos, self ; genesis, birth.] Repro- 
ducing spontaneously, appL body- 

autogeny (otoj'gm) n. Autogenesis. 

autogony (otog'oni) n. [Gk. autos, 
self; gonos, offspring.] Auto- 

autolysis (otol'isis) n. [Gk. autos, 
self; lysis, a loosing.] Self- 

automixis (ot'omik'sis) n. [Gk. autos, 
self; mixis, mingling.] The union 
in a cell of chromatin derived from 
common parentage (biol.). 

autonomic (6t'6n8m'ik) a. [Gk. autos, 
self; nomos, province.] Self- 
governing, spontaneous ; appL 
nerves of sympathetic system and 
of certain involuntary muscles, and 
of secreting glands (phys.). 

autonomous (oton'omus). a. Auto- 

autophagous (6tof'agus) a. [Gk. 
autos, self; phagein, to eat.] Appl. 
birds capable of running about and 
securing food for themselves when 
newly hatched (zool.). 

autophya (6t'6ffa) n.plu. [Gk. autos, 
self; phyein, to produce.] Ele- 
ments in the formation of a shell 
secreted by the animal itself; cf. 
xenophya (zool.). 

autophyllogeny (ot'of iloj'eni) n. [Gk. 
autos, self; phyllon, leaf; genos, 

birth.] Growth of one leaf upon 
or out of another (bot.). 

autophyta (ot'ofl'ta) n. plu. [Gk. 
autos, self; phyton, plant.] Plants 
which obtain food in the ordinary 
way ; cf. saprophyta (bot.). 

autoskeleton (6t'6skel'6ton) n. [Gk. 
autos, self ; skeletos, dried.] A true 
skeleton formed within the animal 

autostylic (ot'ostil'ik) a. [Gk. autos, 
self; stylos, pillar.] Having the 
mandibular arch self-supporting, 
and articulating with the skull 
direct (zoo!.). 

autotomy (otot'omi) n. [Gk. autos, 
self; tome, cutting.] Self-amputa- 
tion of a part, as in certain worms 
and arthropods (zoo/.). 

autotrophic (ot'otrof'ik) a. [Gk. autos, 
self; trephein, to nourish.] Procur- 
ing food independently ; appl. 
plants which are neither sapro- 
phytic nor parasitic (dot.). 

autotropism (6t6t'ropizm) n. [Gk. 
autos, self; trepein, to turn.] 
Tendency to grow in a straight 
line ; appl. plants unaffected by 
external influence (phys.). 

autozooid (ot'ozooid) n. [Gk. autos, 
self ; zoon, animal ; eidos, resem- 
blance.] An independent alcyona- 
rian zooid or individual (zool.). 

auxetics (oksSt'iks) n. plu. [Gk. 
auxein, to increase.] A term appl. 
chemical agents which induce cell- 
division in leucocytes and other 
cells (cyt.\ 

auximone (ok'simon) n. [Gk. auxi- 
mos, promoting growth.] An 
accessory growth - stimulating or 
promoting factor in the food of 
plants (biol.). 

auxospore (ok'sospor) n. [Gk. auxein, 
to increase ; sporos, seed.] A 
diatom which, having reached its 
limit of size, by bi-partition escapes 
from its valve, and uniting with a 
similar one gives rise to a new 
plant (bot.). 

auxotonic (ok'soton'ik) a. [Gk. 
auxein, to increase ; tonos, strain.] 
Induced by growth ; appl. move- 
ments of immature plants ; opp. 
alassotonic (bot.) ; appl. contraction 
against an increasing resistance 



avenaceous (avena'shus) a. [L. avena, 
oats.] Pert, oats (dot.). 

avicularium (avTkula'rTum) n. [L. 
avicula, dim. of avis, bird.] In 
Polyzoa a modified zooecium with 
muscular movable attachments re- 
sembling a bird's beak (zool.). 

awn (on) ;/. [Ger. ahne } chaff.] The 
"beard" of grass, grain, etc. (hot.). 

axial (ak'sial) a. [L. axis, axis.] Pert. 
axis or stem (btol.). 

axial filament, the central filament 
of any structure such as the stiff 
radiating pseudopodia of some of 
the Protozoa (zool.) 

axial sinus, a nearly vertical canal 
in the Echinoderms opening into 
the internal division of the oral ring 
sinus, and communicating aborally 
with the stone canal (zool.). 

axial skeleton, the skeleton of the 
head and trunk, as ofip. the skeleton 
of the limbs (zool.). 

axil (ak'sil) n. [L. axilla, arm-pit.] 
The angle between a leaf or branch 
and the axis from which it springs 

axile (ak'sil) a. [L. axilla, arm-pit.] 
Pert., situated in or belonging to 
the axis ; appl. placentation (bot.). 

axilemma (ak'silSm'a) n. [L. axis, 
axis ; Gk. lemma, husk.] In medul- 
lated nerve fibres, the sheath 
supposed to surround the axial 
cylinder (anat.). 

axilla (aksll'a) n. [ L. axilla, arm-pit.] 
The ami-pit (anat.) ; an axil (bot.). 

axillary (ak'silari, aksil'ari) a. [L. 
axilla, arm-pit.] Pert, the axil ; 
growing in the axil, as buds (bot.) ; 
pert, the arm-pit (anat.). 

axipetal (aksip'Stal) a. [L. axis, axis ; 
Petere, to seek.] Passing towards 
the attachment of the axon, appl. 
nerve impulses (phys.). 

axis (ak'sis) n. [L. axis, axis.] The 
main stem or central cylinder (bot.) ; 
the fundamentally central line of a 
structure ; the second cervical 
vertebra (anat.). 

axis cylinder, the central tract of a 
nerve fibre, the impulse transmitter 

axon (ak'son) n. [Gk. axon, axle.] 
The axis-cylinder process of a multi- 
polar nerve-cell (anat.). 

axoneme (ak'sonem) n. [Gk. axon, 

axle ; ntma, thread.] One of the 
three threads of the main strand 
of an infusorian stalk (zool.). 

axoiiost (ak'sonost) n. [Gk. axon, 
axle ; osteon, bone.] The basal 
portion of rods supporting the 
dermotrichia of fin-rays (zool.). 

axopodium (ak'sopo'dlum) n. [Gk. 
axon, axle ; pous, foot.] A pseudo- 
podium with axial filament (zool.). 

axostyle (ak'sostll) n. [Gk. axon,a.\\& ; 
stylos, pillar.] A slender flexible 
rod of organic substance forming a 
supporting axis for the body of 
many Flagellates (zool.). 

azygobranchiate (azl'gobrang'kiat) a. 
[Gk. a, without ; zygon, yoke ; 
brangchia, gills.] Having the gills 
or ctenidia not developed on one 
side (zool.). 

azygomatous (a'zlgom'atus) a. [Gk. 
a, without ; zygoma, a bar.] With- 
out a zygoma or cheek-bone arch 

azygos (azi'gos, az'igos) n. [Gk. a, 
without ; zygon, yoke.] An un- 
paired muscle, artery, vein, process 

azygosperm (azi'gospe'rm) . [Gk. 
a, without ; zygon, yoke ; sfierma, 
seed.] An azygospore. 

azygospore (azl'gospor) n. [Gk. a, 
without ; zygon, yoke ; sporos, seed.] 
A spore developed directly from a 
gamete without conjugation (bot.). 

azygous (azl'gus, az'Igus) a. [Gk. a, 
without ; zygon, yoke.] Unpaired. 


bacca (bak'a) n. [L. bacca, berry.] 
A pulpy fruit (bot.). 

baccate (bak'at) a. [L. bacca, berry.] 
Pulpy, fleshy (bot.). 

bacciferous (bakslf'grus) a. [L. bacca, 
berry ; ferre, to bear.] Berry-pro- 
ducing (bot.). 

bacciform (bak'slform) a. [L. bacca, 
berry ; forma, shape.] Berry- 
shaped (bot.). 

bacillus (basll'us) n. [L. bacillum, 
small stick.] An elongated rod- 
like bacterium ; a single-celled 
fungus (bot.). 

bacteriology (bak'tertol'ojl) n. [Gk. 




bakterion, rod ; logos, discourse.] 
The science dealing with the life- 
history, structure, and effects of 

bacteriolysin (bakte'rioli'sin) n. [Gk. 
bakterion, small rod ; lyein, to loose.] 
A substance which neutralizes the 
toxicity of or destroys Bacteria 

balancers (bal'anserz) n. plu. [L. 
bilanx, having two scales.] The 
halteres or poisers of dipterous 
insects (zoo!.}. 

balanoid (bal'anoid) a. [Gk. balanos, 
acorn; eidos, like.] Pert, barnacles; 
acorn-shaped (zool.). 

balausta (balos'ta) n. [Gk. balaustion, 
tree-blossom.] Any fruit, many- 
celled, many-seeded, indehiscent 
and with tough pericarps (dot.}. 

baleen (balen') n. [L. balaena, whale.] 
The horny plates attached to the 
upper jaw of true whales ; whale- 
bone (zool.). 

balm (bam) n. [L. balsamum, balsam.] 
A fragrant garden plant ; a soothing 
ointment (bot.). 

balsamiferous (bal'samif 6rus) a. [L. 
balsamum, balsam ; ferre, to bear.] 
Producing balsam (bot.). 

barb (barb) . [L. barba, beard.] One 
of delicate thread-like structures 
extending obliquely from a feather 
rachis, and forming the vane (zool.} ; 
a hooked hair-like bristle (dot.). 

barbate (bar'bat) a. [L. barba, beard.] 
Bearded (bot., zool.). 

barbel (bfr'bel) n. [L. barbus, barbel.] 
A tactile process arising from the 
head of various fishes (zool.). 

barbellate (barbeTat, ba/bglat) a. 
[L. barba, beard.] With stiff 
hooked hair-like bristles (bot.). 

barbicel (bar'bisgl) n. [L. barba, 
beard.] Small process on a feather 
barbule (zool.). 

barbula (bar'bula) n. [L. barbula, 
dim. of barba, beard.] Row of teeth 
of the peristome of mosses (bot.). 

barbule (bar'bul) n. [L. barbula, dim. 
of barba t beard.] One of the small 
hooked processes fringing the barbs 
of a feather (zool.). 

barotaxis (barbtak'sis) n. [Gk. baros, 
weight ; taxis, arrangement.] The 
reaction against a pressure stimulus 

(ba'sal) a. [L. basis, base.] 
Pert, at or near the base, 
basal ganglia, ganglia connecting 
cerebrum with other centres 


basal granule, a thickening at the 
base of a flagellum, the centrosome, 
in certain Protozoa (zool.). 

basal leaf, one of the leaves pro- 
duced near the base of the stem 

basal placenta, arises from the proxi- 
mal end of ovary (bot.). 

basal plates, certain plates in 
Echinoderms, which are situated 
at the top or near the top of the 
stalk in Crinoids, and in Echinoids 
form part of the apical disc (zool.). 

basal wall, the first plane of division 
of the oospores of Ferns and Mosses 

basale (basa'le, basal'a) ., basalia 
(basa'lia) plu. [L. basis, base.] A 
bone of variable structure arising 
from the fusion of pterygiophores 
and supporting fish fins (zool.). 

basement membrane, themembrane 
of a gland containing the acini or 
special secreting portions (anat.}. 

basialveolar (ba'sTalve'olar) a. [L. 
basis, base ; alveolus, hollow.] Ex- 
tending from basion to centre of 
alveolar arch (anat.). 

basibranchial (ba'sibrang'klal) n. 
[Gk. basis, base ; brangchia, gills.] 
The median ventral or basal 
skeletal portion of a branchial 
arch (zool.}. 

basichromatin (ba'sikro'matin) n. 
[Gk. basis, base ; chroma, colour.] 
The deeply staining substance of 
nuclear network ; chromatin (cyt.). 

baslconic sensillae, upright conical 
clavate sense hairs, immovable at 
their base and having thin chitinous 
covering (zool). 

basicranial (ba'sikra'nTal) a. [Gk. 
basis, base ; kranion, skull.] Situ- 
ated at the base of the skull 

basidiophore (basid'Iofor) n. [Gk. 
basis, base ; pherein, to bear.] A 
sporophore which carries basidia 

basidlospore (bastd'iospor) n. [Gk. 
basis, base ; sporos, seed.] A 
spore or gonidium abstricted from 




a basidium ; a basidiogonidium 

basidium (basld'ium) n. [Gk. basis, 
base.] A special cell of certain 
Fungi forming spores by abstriction 

basidorsal (ba'sidor'sal) a. [L. basis, 
base ; dorsum, back.] Appl. a 
small cartilaginous neural plate 
which fuses with the neural process 
in the adult (emb.). 

basiflxed (ba'sifiksd) a. [L. basis, 
base ; figere, to make fast.] At- 
tached by the base ; innate, or 
having the filament attached to 
base of anther (tot.). 

basifugal (ba'sTfu'gal, baslf'ugal) a. 
[L. basis, base ; fugere, to flee.] 
Growing away from the base (bot.). 

basigamous (basTg'amus) a. [Gk. 
basis i base ; gatnos, marriage.] 
Having the oosphere reversed in 
the embryo-sac (bot.). 

basihyal (ba'sihral) n. [Gk. basis, 
base ; hyoeides, Y-shaped.] Broad 
median plate, the basal or median 
ventral portion of the hyoid arch 

basilar (bas'ilar) a. [L. basis, base.] 
Pert, or near the base ; appl. artery, 
crest, membrane, plexus (anat.), 
plate (smb.), style (tot.). 

basilic (basil'ik) a. [Gk. basilikos, 
royal.] Appl. a large vein on the 
inner side of the biceps of the arm 

basilingual (ba'siling'gwal) a. [L. 
basis, base ; lingua, tongue.] Appl. 
a broad flat cartilaginous plate, the 
body of the hyoid, in crocodiles, 
turtles, and amphibians (zoo/.). 

basioccipital (ba'sioksTp'ital) n. [L. 
past's, base ; occiput, back of head.] 
The median ventral bone or element 
in the occipital region of the skull 

basion (ba'slon) n. [L. basis, base.] 
The middle of the anterior margin 
of the foramen magnum (anat.). 

basiophthalmite (ba'slofthal'mlt) n. 
[Gk. basis, base ; ophthalmos, eye.] 
The proximal joint of the eye-stalk 
in Crustaceans (zoo/.). 
basipetal (basip'etal) a. [Gk. basis, 
base ; L. petere, to seek.] Develop- 
ing from apex to base ; appl. leaves 
and inflorescences (tot.). 

basipodite (baslp'odlt) n. [Gk. basis, 
base ; pous, foot.] The second or 
distal joint of the protopodite of 
certain limbs of Crustacea (zool.). 

basipterygium (ba'sTptgrij'ium) tt. 
[Gk. basis, base ; pterygion, little 
wing.] A large flat triangular bone 
in the pelvic fin of Teleosts, and a 
bone or cartilage in other fishes 

basipterygoid (ba'sYpt&tgoid) n. [Gk. 
basis, base ; pterygion, little wing.] 
A process of the basisphenoid in 
some birds (zool.). 

basisphenoid (ba'stsfe'noid) n. [Gk. 
basis, base ; sphen, wedge ; eidos, 
resemblance.] A cranial bone 
between the basioccipital and pre- 
sphenoid (zool.). 

basitemporal (ba'sTtem'poral) n. [L. 
basis, base ; temporalis, temporary.] 
A broad membrane bone covering 
the basisphenoidal region of the 
skull (zool.). 

basivertebral (ba'siveYtgbral) a. [L. 
basis, base ; vertebra, vertebra.] 
Appl. vertebral veins emerging on 
the posterior surface (anat.). 

basophil (ba'sofil) a. [Gk. basis, 
base ; philein, to love.] Appl. 
leucocytes having a strong affinity 
for basic dyes (phys.). 

bast (bast) n. [A.S. baest, bast.] The 
inner fibrous bark of certain trees ; 
the strong fibre obtained from 
certain trees ; phloem (tot.). 

bastard wing, the ala spuria, con- 
sisting of three quill feathers borne 
on the first digit of bird's wing 

bathy limnetic (bath'ilTmngt'ik)a. [Gk. 
bathys, deep ; limnetes, living in 
marshes.] Living or growing in 
the depths of lakes or marshes. 

bathypelagic (bath'ipglaj'Ik) a. [Gk. 
bathys, deep ; pelagos, sea.] In- 
habiting the deep sea (zool.). 

bathy smal (bathlz'mal) a. [Gk. bathys, 
deep.] Pert, the deepest depths of 
the sea (zool.). 

batrachian (batra'kTan) a. [Gk. ba- 
trachos, frog.] Relating to frogs 
and toads (zool.). 

bdelloid (deToid) a. [Gk. bdella, 
leech ; eidos, resemblance.] Leech- 
like, or having the appearance of a 
leech (zool.). 




beard (herd) n. [A.S. beard, a beard.] 
Any of the arrangements of hairs 
on the heads of animals which 
resemble a man's beard (zool.) ; 
the barbed or bristly hair-like out- 
growths on grain (hot.}. 

belemnoid (beTemnoid, bglem'noid) a. 
[Gk. belemnon, dart ; eidos, resem- 
blance.] Shaped like a dart (zool?) ; 
appl. styloid process (anat.). 

bell nucleus, a solid mass of cells, 
derived from the ectoderm and lying 
between the ordinary ectoderm and 
the mesogloea at the apex of the 
medusoid bud, which later becomes 
hollow and ultimately forms the 
sub-umbral cavity of the medusoid 

Bellini's ducts, the larger ducts 
opening at the apex of a kidney 
papilla, and formed by the union 
of smaller collecting tubules (anat.). 

benthos (ben'thos) n. [Gk. benthos, 
depths of the sea.] The fauna and 
flora of the bottom of the sea 

berry (beYi) n. [A.S. berie, berry.] 
The egg of a lobster, or of a cray- 
fish ; the dark knob-like structure 
on the bill of the swan (zool?) ; a 
small, pulpy fruit (hot?). 

betulin (bet'ulm) n. [L. betula, birch 
tree.] A substance derived from 
the outer bark of the birch (phys.). 

biacuminate (bl'aku'minat) a. [L. bis, 
twice ; acumen, point.] Having 
two tapering points (dot.). 

biarticulate (bl'artik'ulat) a. [L. bis, 
twice ; articulus, joint.] Two- 
jointed (hot., sool.). 

bicapsular (blkap'sular) a. [L. bis, 
twice ; capsula, little box.] Having 
two capsules or vessels (hot.}. 

bicarinate (bikar'mat) a. [L. bis, 
twice ; carina, keel.] With two 
keel-like processes (hot., zool?). 

bicarpellate (blkar'pe'lat) a. [L. bis, 
twice ; Gk. karpos, fruit.] With 
two carpels (tot.). 

blcaudate (blko'dat) a. [L. bis, twice ; 
cauda, tail.] Possessing two tail- 
like processes, as the wings of 
Lepidoptera (zool?). 

blcellular (blseTular) a. [L. bis, twice ; 
cellula, little cell.] Composed of 
two cells (to/.). 

bicepa (bl'seps) n. [L. bis, twice ; 

caput, head.] A muscle with two 
heads or origins (anat?). 

bicipltal (blsip'ital) a. [L. bis, twice ; 
caput, head.] Pert, biceps (anat?). 

bicipital groove, a groove on the 
upper part of the humerus (anat.). 

bicollateral (bl'kolat'eral) a. [L. bis, 
twice ; con, together ; latus, side.] 
Having the two sides similar. 

bicolligate (blkol'igat) a. [L. bis, 
twice ; cum, together ; ligare, to 
bind.] With two stretches of web- 
bing on the foot (zool?). 

biconjugate (blkon'joogat) a. [L. bis, 
twice ; cum, with ; jttgum, yoke.] 
With two similar sets of pairs 

bicornute (bikor'nut) a. [L. bis, twice ; 
cornu, horn.] With two horn-like 
processes (zool?). 

bicostate (bikos'tat) a. [L. bis, twice ; 
costa, rib.] Having two longitudinal 
ridges or ribs, as in a leaf (bot.). 

bicrenate (blkre'nat) a. [L. bis, twice ; 
crena, notch.] Doubly crenate, 
as leaves with notched toothed 
margins (tot.). 

blscuspid (bikiis'pid) a. [L. bis, twice ; 
cuspis, point.] Having two cusps 
or points (bot., zool.). 

bicuspid, n. A premolar tooth 

bicuspid valve, the mitral valve of 
the heart (anat.). 

bicyclic (blsik'lik) a. [L. bis, twice ; 
Gk. kyklos, circle.] Arranged in 
two whorls (bot?). 

Bidder's ganglia, a collection of 
nerve-cells in the frog, in the region 
of the auriculo-ventricular groove, 
whence fibres are distributed to the 
rest of the heart (zool.). 

Bidder's organ, a rudimentary ovary 
attached to the anterior end of the 
generative organs in both sexes 
in the toad ; it disappears in old 
females, but is large in old males 
and has been known to become 
functional (zool.). 

bidental (blden'tal) a. [L. bis, twice ; 
dens, tooth.] Having two teeth, or 
tooth-like processes. 

bidenticulate (bi'dgntik'ulat) a. [L. 
bis, twice ; dens, tooth.] With two 
small teeth or tooth- like processes, 
as some scales (zool.). 

biennial (blen'ial) a. [L. bis, twice ; 




annus, year.] Lasting for two 
years (tot.). 

bifacial (blfa'slal, blfa'shal, blfas'yal) 
a. [L. fa's, twice ; fades, face.] 
Appl. leaves with distinct upper 
and lower surfaces ; dorso-ventral 

bifarious (blfa'rlus) a. [L. bis, twice ; 
fart, to speak.] Arranged in two 
rows ; one row on each side of 
an axis (tot.). 

bifid (bifid) a. [L. bis, twice ; findere, 
to split.] Forked, opening with a 
median cleft (zool., tot.). 

biflabellate (bfflabel'at) a. [L. bis, 
twice ; flabellum, fan.] Doubly 
flabellate, each side of the antennal 
joints sending out flabellate pro- 
cesses (zool.}. 

biflagellate (blflajeTat) a. [L. bis, 
twice ; flagellum, whip.] Having 
two lash-like appendages or flag- 
ella (zool., bot.). 

biflex (bl^ks) a. [L. bis, twice ; 
flectere, to bend.] With two 

biflorate (blflo'rat) a. [L. bis, twice ; 
flora, flowers.] Producing two 
flowers, or bearing two flowers 

bifoliate (bifo'liat) a. [L. bis, twice ; 
folium, leaf.] Appl. compound leaf 
with two leaflets (bot.). 

biforin (blf'orin) . [L. bis, twice ; 
fort's, door.] An oblong raphidian 
cell opening at each end (bot.). 

bifurcate (blfur'kat) a. [L. bis, twice; 
/urea, fork.] Forked ; having two 
prongs (bot., zool.) ; having two 
joints, the distal V-shaped and 
attached by its middle to the 
proximal (zool.). 

bigeininate (bijem'inat) a. [L. bis, 
twice ; gcminus, double.] Doubly- 
paired ; twin-forked (bot.). 

bljugate (bijoo'gat) a. [L. bis, twice ; 
jugare, to join.] With two pairs of 
leaflets (bot.). 

bilabiate (bila'biat) a. [L. bis, twice ; 
labium, lip.] Two-lipped, as some 
corollas (tot.). 

bilamellar (bllam'elar, bllameTar) a. 
[L. bis, twice ; lamella, plate.] 
Formed of two plates ; having two 
lamellae (bot., zool.). 

bilaminar (bllam'inar) a. [L. bis, 
twice; lamina, thin plate.] Having 

two plate-like layers ; diploblastic 

bilateral (bllat'eral) a. [L. bis, twice ; 
latus, side.] Having two sides 
symmetrical about an axis. 

bile (bil) n. [L. bilis, bile.] The 
secretion of the liver (phys.). 

biliary (bil'iari) a. [L. bilis, bile.] 
Conveying or pert, bile (phys.). 

bilicyanin (bil'isl'anin) n. [L. bilis, 
bile ; Gk. kyanos, dark blue.] A 
blue pigment found in renal calculi 

bilirubin (bil'iroo'bin) n. [L. bilis, 
bile ; ruber, red.] A reddish-yellow 
bile pigment (phys.). 

biliverdin (bil'Tvgr'din) . [L. bilis, 
bile ; F. vert, green.] A green bile 
pigment formed by oxidation of 
bilirubin (phys.). 

bilobate (bllo'bat) a. [L. bis, twice ; 
Gk. lobos, rounded flap.] Having 
two lobes. 

bilobular (bllob'ular) a. [L. bis, 
twice ; L. Ipbulus, dim. of lobus, 
lobe.] Having two lobules. 

bilocellate (bfloseTat) a. [L. bis, 
twice ; locellus, dim. of locus, place.] 
Divided into two compartments 

bilocular (bllok'ular) a. [L. bis, twice ; 
locus, place.] Containing two 
cavities or chambers (bot.). 

biloculine (bllok'ulin) a. [L. bis, 
twice ; loculus, little place.] Two- 

bilophodont (bllof'odont) a. [L. bis, 
twice ; Gk. lophos, ridge ; odous, 
tooth.] Appl. molar teeth of tapir, 
which have ridges joining the two 
anterior and two posterior cusps 

bimaculate (blmak'ulat) a. [L. bis, 
twice ; macula, spot.] Marked 
with two spots or stains (zool.). 

bimanous (blm'anus) a. [L. bis, twice ; 
manus, hand.] Having two hands ; 
appl. certain of the primates 

bimastism (blmas'tizm) n. [L. bis, 
twice ; Gk. mastos, breast.] Condi- 
tion of having two mammae (zool.). 

bimuscular (blinus'kular) a. [L. bis, 
twice ; musculus, muscle.] Having 
two muscles (zool.). 

binary fission, the division of a cell 
into two by an apparently simple 




division of nucleus and cytoplasm 

binary nomenclature, see binomial 

binate (bi'nat) a. [L. dint, two by 
two.] Appl. leaf composed of two 
leaflets ; growing in pairs (hot.}. 

binodal (bino'dal) a, [L. bis, twice ; 
nodus, nob.] Having two nodes, 
as the stem of a plant (bot.}. 

binomial (blno'mial) a. [L. bis, twice ; 
nomen, name.] Consisting of two 
names (biol.}. 

binomial nomenclature, the system 
of double names given to plants 
and animals, first the generic 
name, then the specific, as Felis 
(genus) tigris (species). 

binomialism (blnd'mTalTzm) n. [L. 
bis, twice ; nomen, name.] The 
system of binomial nomenclature 

binuclear (blnu'klear) a. [L. bis, 
twice ; nucleus, small nut.] Having 
two nuclei (biol.}. 

binucleate, binuclear. 

bioblast (bl'oblast) n. [Gk. bios, life ; 
blastos, bud.] A biophore (biol.}. 

biocellate (blosel'at) a. [L. bis, twice ; 
ocellus, dim. oioculus, eye.] Having 
two ocelli (zool.}. 

biochemistry (bl'dkem'Tstri) n. [Gk. 
bios, life ; chemos, juice.] The 
chemistry of living organisms (biol.}. 

biocoenosis (bl'bseno'sis) n. [Gk. 
bios, life ; koinos, common.] Asso- 
ciation of forms of life on any given 
feeding area (biol}. 

biodynamics (bl'odinam'fks) . [Gk. 
bios, life ; dynamis, power.] The 
science of the active vital phe- 
nomena of animals (phys.}. 

biogen (bl'b'jen) n. [Gk. bios, life ; 
genos, offspring.] A hypothetical 
vital unit (biol.}. 

biogenesis (bl'qjen'gsis) n. [Gk. bios, 
life ; genesis, birth.] The theory of 
the descent of living matter from 
living matter omne vivum e vivo ; 
opp. abiogenesis (biol.}. 

blogenetic law, recapitulation 

biogenous (bioj'enus) a. [Gk. bios, 
life ; genos, offspring.] Inhabiting 
living organisms, as Bacteria (biol.}. 

biogeny (bloj'6ni) n. [Gk. bios, life ; 
genesis, birth.] The science of the 

evolution of organisms, comprising 
ontogeny and phylogeny (biol.}. 

biogeography (bi'ojeog'rafi) n. [Gk. 
bios, life ; ge, earth ; graphein, to 
write.] The part of biology dealing 
with the geographical distribution 
of plants (phytogeography) and 
animals (zoogeography) ; chorology. 

biological (blolqj'ikal) a. [Gk. bios, 
life ; logos, discourse.] Relating to 
the science of life (biol.}. 

biology (blol'oji) n. [Gk. bios, life ; 
logos, discourse.] The science of 

biometrics (blomet'riks) ;/. [Gk. bios, 
life ; metron, measure.] The stat- 
istical study of living organisms. 

biometry (blom'e'tri), biometrics. 

bion (bl'on) n. [Gk. bion, living.] An 
independent living organism. 

bionergy (blon'erji) n. [Gk. bios, life : 
energda, action.] Vital force. 

bionomics (blonom'Tks) n. [Gk. bios, 
life ; nomos, law.] The study of 
organisms in relation to their 

biophore (bl'ofor) n. [Gk. bios, life ; 
pherein, to carry.] A hypothetical 
vital unit, of which a group forms 
a determinant. 

biophyte (bl'oflt) n. [Gk. bios, life ; 
phyton, plant.] A plant which gets 
sustenance from living organisms 

bioplasm (bl'b'plazm) n. [Gk. bios, 
life ; plasma, something moulded.] 
Living matter ; protoplasm (biol.). 

bioplast (bl'bplast) n. [Gk. bios, life ; 
plasma, something moulded.] A 
minute quantity of living proto- 
plasm capable of reproducing itself 

biorgan (blpr'gan) n. [Gk. bios, life ; 
organon, instrument.} An organ in 
the physiological sense, not neces- 
sarily a morphological unit (biol.}. 

bios (bi'os) n. [Gk. &ws,\ite.] Organic 
life, plant or animal. 

biostatics (bl'ostat'iks) n. [Gk. bios, 
life ; statos, stationary.] The branch 
of physiology dealing with structure 
in relation to function (phys.}. 

biota (blo'ta) n. [Gk. bios, life.] The 
fauna and flora of a region. 

biotic (blot'ik) a. [Gk. bios, life.] 
Pert, life ; vital (biol.}. 

biotonus (bl'oto'nus) . [Gk. bios, 




life ; tonos, strain.] The ratio 
between assimilation and dissimila- 
tion of the biogens (phys.). 

biovulate (blov'ulat) a. [L. bis, twice ; 
ovum, egg.] Containing two ovules 

bipaleolate (blpal'eolat) a. [L. bis, 
twice ; palea, chaff.] Furnished 
with two small paleae (bot.). 

bipalmate (blpal'mat) a. [L. bis, 
twice ; palma, palm of the hand.] 
Lobed with the lobes again lobed 

biparietal (bl'parl'gtal) a. [L. bis, 
twice ; paries, wall.] Linking up 
or connected with the two parietal 
eminences (anat.). 

biparous (bip'arus) a. [L. bis, twice ; 
parere, to beget.] Having two 
young at a time (zool.). 

blpectinate (blpgk'tinat) a. [L. bis, 
twice ; pecten, comb.] Having the 
two margins furnished with teeth 
like a comb (bot., zool.). 

biped (bl'ped) . [L. bis, twice ; pes, 
foot.] A two-footed animal. 

bipennlform (blpgn'iform) a. [L. bis, 
twice ;penna, feather ; forma, shape.] 
Feather-shaped, with the sides of 
the vane of equal size ; appl. some 
muscles (anat.). 

bipetalous (blpet'alus) a. [L. bis, 
twice ; Gk.petalon, leaf.] With two 
petals (bot.). 

bipinnaria (bipina'ria) n. [L. bis, 
twice ; pinna, feather.] An aster- 
oid larva with pre-oral and post-oral 
bands of cilia (zool.). 

bipinnate (blpln'at) a. [L. bis, twice ; 
pinna, feather.] Having leaflets 
growing in pairs on paired stems 

bipinnatifid (bl'pinat'ifid) a. [L. bis, 
twice ; pinna, feather ; findere, to 
cleave.] With leaves segmented 
and these segments again divided 

bipinnatlpartite (bi'pinat'ipartlt) a. 
[L. bis, twice ; pinna, feather ; 
partiri, to divide/] Bipinnatifid, 
but with divisions extending nearly 
to the midrib (bot.). 

bipinnatisect (bl'plnat'isekt) a. [L. 
bis, twice ; pinna, feather ; secare, 
to cut.] Bipinnatifid, but with 
divisions extending to the midrib 

biplicate (bip'likat) a. [L. bis, twice ; 
plicare, to fold.] Having two folds. 

bipocillus (bl'pbsil'us) n. [L. bis, 
twice ; pocillum, a little cup.] A 
microsclere with curved shaft and 
cup-shaped expansion at each end 

bipolar (blpo'lar) a. [L. bis, twice ; 
Gk. polos, pivot.] Having a pro- 
cess at each end or pole, appl. 
nerve cells (anat.). 

bipolarity (bl'polaYrti) n. [L. bis, 
twice ; Gk. polos, pivot.] The 
condition of having two polar pro- 
cesses ; the condition of having 
two distinct poles, as the vegetative 
and animal poles in an egg (biol.). 

biramose (blra'm5s) a. [L. bis, twice ; 
ramus, branch.] Divided into two 

biramous, biramose. 

birostrate (blros'trat) a. [L. bis, 
twice ; rostrum, beak.] Furnished 
with two beak-like processes. 

birth pore, the uterine pore of 
Trematodes and Cestodes ; the 
birth-opening of the rediae of Tre- 
matodes (zool.). 

biseptate (blsep'tat) a. [L. bis, twice ; 
septum, fence.] Having two parti- 

biserial (blse'rlal) a. [L. bis, twice ; 
series, series.] Arranged in two 

biserrate (biser'at) a. [L. bis, twice ; 
serra, saw.] Having marginal teeth 
which are themselves notched (bot.). 

bisexual (blsek'sual, blsek'shual) a. 
[L. bis, twice ; sexus, sex.] Having 
both male and female reproductive 
organs (biol.). 

bistephanic (bl'stefan'lk) a. [L. bis, 
twice ; Gk. Stephanos, crown.] 
Joining the two points where the 
coronal suture crosses the superior 
temporal ridges (anat.). 

bistipulate (blstip'ulat) a. [L. bis, 
twice ; stipitla, stem.] Provided 
with two stipules (bot?). 

bistratose (blstrat'os) a. [L. bis, 
twice ; stratum, layer.] With cells 
arranged in two layers (bot.). 

bisulcate (blsul'kat) a. [L. bis, twice ; 
sulcus, groove.] Havingtwogrooves 

bitemporal (bite"m'p6ral) a. [L. bis, 
twice ; teinporalis, temporary.] 




Appl. the two temporal bones ; a 
line joining the posterior ends of the 
two zygomatic processes (attaf.). 

biternate (blteVnat) a. [L. bis, twice ; 
terni, three by three.] Ternate 
with each division itself again 
ternate (bot.}. 

bivalent (biva'lgnt, biv'algnt) a. [L. 
bis, twice ; valere, to be strong.] 
Appl. a double chromosome (cyt.}. 

bivalve (bl'valv) a. [L. bis, twice ; 
valvae, folding doors.] Consisting 
of two plates or valves, as a mussel 
shell (zool.} ; or a seed-capsule of 
similar structure (bot.}. 

biventer cervlcis (biven'tgr servl'sls) n. 
[L. bis, twice ; venter, belly ; cervix, 
neck.] A muscle of the neck con- 
sisting of two fleshy broad ends 
with a narrow tendinous portion in 
the middle (anat.}. 

biventral (blvSn'tral) a. [L. bis, twice; 
venter, belly.] Appl. muscles of the 
biventer type (anat.}. 

bivittate (bivit'at) a. [L. bis, twice ; 
vitta, band.] With two oil re- 
ceptacles (bot.} ; with two stripes 

bivium (blv'lum) n. [L. bis, twice ; 
via, way.] Generally the posterior 
pair of ambulacral areas in certain 
Echinoidea ; the two rays between 
which the madreporite lies (zool.}. 

bladder (blad'er) n. [A.S. blaedre, 
bag.] A membranous sac filled 
with air or fluid (bot., zool.}. 

bladder-worm stage, the cysticercus 
stage in tapeworms (zool.}. 

blade (blad) n. [A.S. blaed, leaf.] The 
flat part of the leaf of grasses 

blastaea (blaste'a) n. [Gk. blastos, 
bud.] A planaea or ciliated planula, 
a hypothetical stage in evolution 

blastelasma (blas'tglaz'ma) n., blastel- 
asmata (blas'teiaz'mata) plu. [Gk. 
blastos, bud ; elasma, plate.] Any 
germ layer formed after the forma- 
tion of the epiblast and hypoblast 

blastema (blaste'ma) n., blastemata 
(blaste'mata) plu. [Gk. blastema, 
bud.] The formative substance in 
an egg ; the primordium of an 
organ (etnb.}; the thallus of a lichen 

blastocarpous (blas'tokar'pus) a. [Gk. 
blastos, bud; karpos, fruit.] De- 
veloping while still surrounded by 
the pericarp (bot.}. 

blastocheme (blas'tokem) n. [Gk. 
blastos, bud ; ochema, vessel.] A 
reproductive individual in some 
Medusae (zool.}. 

blastochyle (blas'tokll) n. [Gk. blastos, 
bud ; chylos, juice.] The fluid in a 
blastocoel, or segmentation-cavity 

blastocoel (blas'tosel) n. [Gk. blastos, 
bud ; koilos, hollow.] The segmenta- 
tion-cavity of a developing ovum 

blastocolla (blas'tokol'a) n. [Gk. 
blastos, bud ; kolla, glue.] A gummy 
substance coating certain buds (bot.}. 
blastocyst (blas'tosist) . [Gk. blastos, 
bud ; kystis, bladder.] The germinal 
vesicle (emb.}. 

blastoderm (blas'toderm) n. [Gk. 
blastos, bud ; derma, skin.] The 
germinal disc (smb.}. 
blastodermic vesicle, ahollow sphere 
of cells, an earlystage in the develop- 
ment of a fertilized ovum (emb.}. 
blastodisc (blas'todisk) n. [Gk. blastos, 
bud ; diskos, disk.] The germinal 
area of a developing ovum (emb.}. 
blastogenesis (blas'tqjen'esls) n. [Gk. 
blastos, bud ; genesis, birth.] Gem- 
mation or reproduction by bud- 
ding ; transmission of inherited 
characters by means of the germ- 
plasm only (biol.}. 

blastogenic (blas'tqjen'ik) a. [Gk. 
blastos, bud ; genos, offspring.] 
Appl. inactive idioplasm unalter- 
able till time and place of activity 
are reached (emb.}. 

blastomere (blas'tomer) n. [Gk. 
blastos, bud ; meros, part.] One of 
the cells formed during the primary 
divisions of an egg (emb.}. 
blastoneuropore (blas'tonu'ropor) n. 
[Gk. blastos, bud ; neuron, nerve ; 
poros, passage.] A temporary 
passage connecting blastopore and 
neuropore (emb}. 

blastophore (blas'tofor) n. [Gk. blastos, 
bud \pherein, to bear.] Embryonic 
origin of plumule (bot.} ; in Alcypn- 
aria the reproductive body, giving 
rise usually to buds ; the central 
part of the spermocyte mass in 




worms, which remains unchanged 
through spermatogenesis (zool.}. 

blastopore (blas'topor) n. [Gk. blastos, 
bud ; poros, passage.] The cavity 
leading into the archenteron of the 
gastrula (etnb.}. 

blastosphere (blas'tosfer) n. [Gk. 
blastos, bud ; sphatra, globe.] The 
blastula, a hollow ball of cells (emb.}. 

blastostyle (blas'tostll) n. [Gk. blastos, 
bud ; stylos, pillar.] In Hydrozoa, 
a columniform zooid with mouth 
and tentacles, or with mouth and 
tentacles absent, bearing gono- 
phores (zool.}. 

blastossooid (blas'tozo'oid) . [Gk. 
blastos, bud ; zoon, animal ; eidos, 
resemblance.] A larval bud in 
case of precocious budding in 
Ascidians (zool.}. 

blastula (blas'tula) n. [L. dim. of Gk. 
blastos, bud.] A hollow globe of 
cells, with wall usually one layer 
thick (emb.}. 

blastulatlon (blas'tula'shun) n. [L. 
blastula, little bud.] Formation of 
blastulae (emb.}. 

bleeding of plants, exudation of 
watery sap from vessels at a cut 
surface, due to root-pressure (bot.}. 

blended inheritance, mixed race or 

blendling (blgn'dlmg) n. [A.S. blan- 
dan, to mix.] A hybrid. 

blepharoblast (bleTaroblast) n. [Gk. 
blepharon, eye-lid ; blastos, bud.] 
See blepharoplast. 

blepharoplast (b!6f aroplast) n. [Gk. 
blepharon, eyelid ; plastos, moulded.] 
A centrosome which is in relation 
to a motor cell organ, as to the 
flagellum of flagellates (zool.}. 

blight (bllt) n. [A.S. blaecan, to grow 
pale.] A disease-producing insect 
or fungus ; a plant disease (bot.}. 

blind spot, the region of the retina 
of the eye where the optic nerve 
enters (anat.}. 

blister (blis'tgr) n. [A.S. blotvan, to 
blow.] A subcutaneous bubble or 
bladder filled with fluid ; a plant 

blood (blud) n. [A.S. blod, blood.] 
The fluid circulating in the vascular 
system of animals, distributing food- 
material and oxygen and collecting 
waste products (phys.}. 

blood cells, cells derived by mitosis 
from the ordinary mesoderm cells, 
at first somewhat similar to lympho- 
cytes ; the primitive haematoblasts 

blood crystals, crystals of haemo- 
globin, haemin, or haematoidin, 
which form when blood is shaken 
up with chloroform or ether (phys.}. 

blood dust, the form in which fat is 
seen in blood cells, by means of 
the ultramicroscope (phys.). 

blood islands, isolated reddish 
patches in the mesoderm in which 
primitive erythroblasts are found 
enclosed in a mesodermal syncytium 

blood platelets, colourless bodies 
about one-third the size of the red 
corpuscles, and nucleated when the 
red corpuscles are nucleated (phys.}. 

blood plates, minuteamoeboid proto- 
plasmic bodies found in the blood, 
each with a small nuclear-like 
structure (phys.}. 

blood serum, the fluid or plasma left 
after removal of the corpuscles and 
fibrin (phys.}. 

blood vessel, any vessel or space in 
which blood circulates ; strictly 
only used in regard to special 
vessels with well - defined walls 

bloom, a layer of wax particles on 
the external surface of certain 
fruits, such as grapes, peaches ; 
the flower of a plant (bot.}. 

blubber (blub'er) n. [M.E. blober, a 
bubble.] The fat of whales, lying 
between the outer skin and muscle 
layer (zool.}. 

blue timber, a wood disease pro- 
duced by fungus, causing a bluish 
discoloration (bot.}. 

body blight, a fungal disease of pear 
trees (bot.}. 

body cavity, the coelom or space in 
which the viscera, etc., lie ; it is 
mesodermal in origin, and is 
schizocoelic or enterocoelic L in 
development (anat.}. 

body cell, a somatic as distinct from 
a germ cell. 

body stalk, a band of mesoderm 
connecting the caudal end of an 
embryo with the chorion (emb.}. 

bone (bon) n. [A.S. ban, bone.] Con- 



nective tissue in which the ground- 
substance is impregnated with salts 
of lime (anat.). 

book gill, a gill composed of delicate 
leaf-like lamellae placed one over 
the other like leaves of a book, as 
seen in Limulus (zool). 

book lung, a gill similar to a book 
gill, but modified for air-breathing, 
and open to the exterior only by a 
small slit, as in Scorpions (zool). 

booted (boot'ed) a. [O. F. boute, boot.] 
Equipped with raised horny plates 
of skin, as feet of some birds 

bordered, pit, a form of pit developed 
on the walls of tracheides, caused 
by a portion of the wall remaining 
unthickened (bot). 

bosselated (bos'elated) a. [M.E. 
bosse, knob.] Covered with knobs, 
as some mollusc shells (zool.}. 

bosset (bos'gt) n. [M.E. bosse, knob.] 
The beginning of horn formation 
in deer in the first year (zool.). 

bostryx (bos'tricks) n. [Gk. bostrychos, 
curl.] A cymose inflorescence with 
blooms on only one side of the axis 

botany (bot'am) n. [Gk. botane, pas- 
ture.] That branch of biology 
dealing with plants. 

bothridium (bothrld'ium) n. [Gk. 
bothros, trench.] A muscular cup- 
shaped outgrowth from scolex of 
Cestoids ; a phyllidium (zool.). 

bothrium (both'rium) n. [Gk. bothros, 
trench.] A sucker ; a sucking 
groove of Cestoids (zool). 

botryoidal (bot'rioidal) a. [Gk. botrys, 
bunch of grapes.] Appl. tissue of 
branched canals surrounding the 
enteric canal in leeches (zool). 

botryose .(bot'rios) a. [Gk. botrys, 
bunch of grapes.] Racemose ; in 
the form of a bunch of grapes 

bouillon (boo'yong) . [F. bouillir, 
to boil.] An infusion of beef for 
the cultivation of germs (phys.). 

Bowman's capsule, the vesicle of an 
excretory tubule, one side of which 
projects into the other, nearly 
filling the cavity (anat). 

Bowman's glands (bo'manz), serous 
glands in the corium of the olfactory 
mucous membrane (anat). 

braccate (brak'at) a. [L. braccae, 
breeches.] Appl. birds having 
additional feathers on legs or feet 

brachelytrous (brakel'itrus) a. [Gk. 
brachys, short ; elytron, wing.] 
Having short elytra, or wing 
covers (zool). 

brachial (bra'kial) a. [L. brachium, 
arm.] Pert, arm, arm-like. 

brachiate (bra'klat) a. [L. brachium, 
arm.] Branched ; having opposite 
paired branches on alternate sides 

brachiferous (brakif'erus) a. [L. 
brachium, arm ; ferre, to carry.] 

brachigerous, brachiferous. 

brachiocephalic (brak'iokefal'ik, -sef-) 
a. [L. brachium, arm ; Gk. kephale, 
head.] Pert, arm and head, appl. 
artery (anat). 

brachiocubital (brak'ioku'bital) a. [L. 
brachium, arm ; cubitum, forearm.] 
Pert, arm and forearm (zool). 

brachiolaria (brakiola'ria) n. [L. 
brachiolum, a small arm.] A larval 
stage in the metamorphosis of 
certain starfishes (zool). 

brachiorachidian (brak'Torakld'ian) a. 
[L. brachium, arm ; Gk. rhachis 
spine.] Pert, arm and spine. 

brachium (brak'ium) n. [L. brach- 
ium, arm.] An arm or branching 
structure ; the upper limb of verte- 
brates (zool). 

brachycerous (brakis'erus) a. [Gk. 
brachys, short ; keras, horn.] Short- 
horned ; with short antennae (zool). 

brachycnemic (brak'ikne'mik) a. [Gk. 
brachys, short ; kneme, tibia.] 
Appl. arrangement of mesenteries 
of Zoanthids where the sixth 
protocneme is imperfect (zool). 

brachydont (brak'idont) a. [Gk. 
brachys, short ; odous, tooth.] Appl. 
molar teeth with low crowns (zool). 

brachyodont, brachydont. 

brachyourous (brak'ioo'rus) a. Brach- 

brachypleural (brak'iploo'ral) a. [Gk. 
brachys, short \pleuron, side.] With 
short pleura or side plates (zool). 

brachypodous (brakip'b'dus) a. [Gk. 
brachys, short ; pous, foot.] With 
short legs (zool), or stalk (bot). 

brachypterous (brakip'tgrus) a. [Gk. 





brachys, short ; pteron, wing.] With 

short wings (zool.). 
brachystomatous (brak'istom'atus) a. 

[Gk. brachys, short ; stoma, mouth.] 

With short proboscis ; appl. certain 

insects {zool.}. 
brachyural (brak'fu'ral) a. [Gk. 

brachys, short ; oitra, tail.] Having 

a short abdomen usually tucked in 

below the thorax ; appl. certain 

crabs (zool.). 
bract (brakt) n. [L. bractea, thin 

plate of metal.] A floral leaf; a 

modified leaf in whose axil a flower 

arises (hot.) ; a hydrophyllium in 

Siphonophora ; the distal exite of 

the sixth appendage of Apus 

bract scales, small scales developed 

directly on the axis of cones ; cf. 

ovuliferous scales (dot.). 
bracteal (brak'teal) a. [L. bractea, 

thin metal plate.] Like a bract 

bracteate (brak'teat) a. [L. bractea, 

thin metal plate.] Having bracts 


bracted, bracteate. 
bractelform (brakte'iform) a. [L. 

bractea, metal plate ; forma, shape.] 

bracteolate (brak'te6lat)#. [L. bractea, 

metal plate.] Appl. flowers with 

bracteoles (bot.). 
bracteole (brfxk'teol) n. [L. bractea, 

metal plate.] Secondary bract at 

the base of flower (bot.). 
bracteose (brak'teos) a. [L. bractea, 

metal plate.] With many bracts 


bractlet, bracteole. 
brain (bran) n. [M.E. brayne, brain.] 

The centre of the nervous system ; 

the mass of nervous matter in 

vertebrates at the anterior end of 

the spinal cord, lying in the skull ; 

in invertebrates, the supraoeso- 

phageal or suprapharyngeal ganglia 

branch (bransh) n. [It. branca, claw.] 
A bough ; a principal outgrowth 
from a stem or axis (bot.) ; a prin- 
cipal division of an artery, vein, or 
nerve (anai.). 

branchia (brang'kia) ., branchiae 
(brang'kle, -kia), plu. [Gk. brang- 
chia, gills.] Gills (zool.). 

branchiae (brang'kiak) a. [Gk. brang- 
chia, gills.] Pert, gills. 

branchial, branchiae. 

branchial arch, one of the bony or 
cartilaginous arches placed on the 
side of the pharynx posterior to the 
hyoid arch, and supporting gill 
bars (zoo/.). 

branchiate (brang'kiat) a. [Gk. 
brangchia, gills.] Having gills 

branchicolous (brangkik'olus) a. [Gk. 
brangchia, gills ; L. colere, to in- 
habit.] Parasitic on fish gills ; appl. 
certain Crustaceans (zool.). 

branchiforra (brang'kiform) a. [Gk. 
brangchia, gills ; L. forma, shape.] 
Gill-like (sool.). 

branchihyal (brang'klhfal) a. [Gk. 
brangchia, gills ; hyoeides, Y-shaped.] 
One of the elements of a branchial 
arch (zool.). 

branchiocardiac (brang'ktokar'diak) a. 
[Gk. brangchia, gills ; kardia, heart.] 
Pert, gills and heart ; appl. vessel 
given off ventrally from the ascidian 
heart (zool.). 

branchiomere (brang'klomer) n. [Gk. 
brangchia, gills ; meros, part.] A 
branchial segment (zool., emb). 

branchiopallial (brang'klopal'lal) a. 
[Gk. brangchia, gills ; L. pallium, 
mantle.] Pert, gill and mantle of 
Molluscs (zool.). 

branchiostegal (brang'klos'tggal) a. 
[Gk. brangchia, gills ; stege, roof.] 
With or pert, a gill cover ; appl. 
membrane, rays, etc. (zool.). 

branchiostege (brang'klostej') n. [Gk. 
brangchia, gills ; stege, covering.] 
The branchiostegal membrane 

branchiostegite (brang'klos'tgglt) . 
[Gk. brangchia, gills ; stege, roof.] 
The expanded lateral portion of the 
carapace forming the gill cover in 
certain Crustaceans (zool.). 

branchireme (brang'klrem) n. [Gk. 
brangchia, gills ; L. remus, oar.] 
A branchiate limb ; any of the 
locomotory and respiratory limbs 
of a Branchiopod (zool.). 

brand (brand) n. [A.S. beornan, to 
burn.] A fungus producing a burnt 
appearance on leaves of trees (tot.). 

bregma (brgg'ma) n. [Gk. bregma, 
fore part of head.] That part of 




the skull where frontals and parietals 
meet (anat.). 

brevicaudate (breVik&'dat) a. [L. 
brevis, short ; cauda, tail.] With a 
short tail (zool.). 

brevifoliate (breVifo'liat) a. [L. 
brews, short ; folium, leaf.] Having 
short leaves (bot.). 

brevillngual (breViling'gwal) a. [L. 
erems, short ; lingua, tongue.] 
With short tongue (zool.). 
breviped (breVipe"d) a. [L. brevis, 
short ; pes, foot.] Having short 
legs ; appl. certain birds (zool.). 
brevipennate (breVipfin'at) a. [L. 
brevis, short ; penna, feather.] With 
short wings (zool.). 

brevirostrate (breViros'trat) a. [L. 
brevis, short ; rostrum, beak.] With 
short beak or bill, of birds (zool.). 
brevissimus oculi, the obliquus in- 
ferior, the shortest muscle of the 
eye (anat.). 

brochidodromous (brok'idod'romus) a. 
[Gk. brochos, loop ; dromein, to run.] 
Appl. nerves in leaves when they 
form loops within the blade (bot.). 
bronchia (brong'kiS) n. plu. [Gk. 
brongchos, tube.] The subdivisions 
or branches of each bronchus 

bronchial (brSng'klal) a. [Gk. brong- 
chos, windpipe.] Pert, the bronchi. 
bronchiole (brong'klol) n. [Gk. 
brongchos, windpipe.] A small 
terminal branch of the bronchi 

bronchopulmonary (brong'kopuTmon- 
arl) a. [Gk. brongchos, windpipe ; 
L. pulmo, lung.] Pert, bronchi and 
lungs (anat.). 

bronchotracheal (brong'kotra'keal) a. 
[Gk. brongchos, windpipe ; L. 
trachea, trachea.] Pert, bronchi 
and trachea (anat.). 
bronchovesicular (brfing'kove'sik'ular) 
a. [Gk. brongchos, windpipe ; L. 
vesicula, little sac.] Pert, bronchial 
tubes and the lung cells (anat.). 
bronchus (brfing'kus) ., bronchi 
(brong'kl, -ke) plu. [Gk. brongchos, 
windpipe.] Tubes connecting the 
trachea with the lungs (anat.). 
brood pouch, a sac-like cavity into 
which the eggs or embryos are 
placed, in which they pass a stage 
of their development ; a space 

formed by overlapping plates 
attached to the bases of the thor- 
acic limbs in certain Crustacea 

brown body, a brown, rounded mass 
of compacted degenerate organs 
in some Polyzoa (zool.). 
Brownian movements, the passive 
vibratory movements of fine gran- 
ules when suspended in a fluid, 
brown funnels, a single pair of 
organs on dorsal aspect of posterior 
end of pharynx, opening posteriorly 
into the atrium, and anteriorly into 
the coelom, supposed to be acces- 
sory excretory organs in Amphioxus 

bryology (brlol'oji) n. [Gk. bryon, 
moss; logos, discourse.] The science 
dealing with mosses (bot.). 
bryophyte (bri'ofit) n. [Gk. bryon, 
moss ; phyton, plant.] Any of the 
mosses or liverworts (bot.). 
bryozoon (bri'ozo'on) n. [Gk. bryon, 
moss ; zoon, animal.] A Polyzoon, 
so named from the moss-like appear- 
ance (zool.). 

buccal (buk'al) a. [L. bucca, cheek.] 
Belonging to the cheek or mouth 

buccinator (buk'sina'tor) n. [L. buc- 
cina, trumpet.] A broad thin muscle 
of the cheek (anat.). 
buccolablal (buk'ola'bial) a. [L. bucca, 
cheek ; labium, lip.] Pert, the 
mouth cavity and lips (anat.). 
buccolingual (buk'oling'gwal) a. [L. 
bucca, cheek ; lingua, tongue.] Pert. 
cheeks and tongue (anat.) 
bucconasal (biik'ona'zal) a. [L. bucca, 
cheek ; nasus, nose.] Pert, cheek 
and nose ; appl. membrane (anat.). 
buccopharyngeal (buk'ofaYinje'al, 
-f&rin'jeal) a. [L. bucca, cheek ; 
G\a.pharyngx, throat.] Pert, cheeks 
and pharynx (anat.). 
bud (bud) n. [M.E. budde, bud.] A 
rudimentary shoot, or flower (bot.) ; 
any outgrowth which will develop 
directly into an exact replica of the 
structure or organism from which 
it grew out (zool.). 

budding (bud'fng) n. [M.E. budde, 

bud.] A method of reproduction 

seen in many primitive animals 


bulb (bulb) n. [L. bulbus, globular 

BUL- 39 

root] A part resembling a bulb 
(anat.} ; a specialized underground 
bud with thick fleshy leaves which 
afford it nourishment during de- 
velopment (bot.~). 

bulbar (bul'bar) a. [L. bulbus, globular 
root] Pert, a bulb or a bulb-like 
part ; generally appl. paralysis from 
a disease of the medulla oblongata 

bulbiferous (bulblfgrus) a. [L. bulbus, 
bulb ;ferre, to carry.] Bulb-bearing 

bulbil (bul'bll) n. [L. bulbus, bulb.] 
A large and fleshy axillary bud 
which may fall and produce a new 
plant, as in some lilies (dot.}. 

bulbonuclear (buTbonu'klear) a. [L. 
bulbus, bulb ; nucleus, kernel.] Pert. 
medulla oblongata and the nuclei of 
the cranial nerves (anat.). 

bulbous (bul'bus) a. [L. bulbus, bulb.] 
Like a bulb ; developing from a 
bulb ; having bulbs (oof.). 

bulbus (bul'bus) n. [L. bulbus, bulb.] 
The knob-like part found in con- 
nection with various nerves (anat.}. 

bulla (bool'a, bul'a) n. [L. bulla, 
water-bubble.] Appl. the rounded 
prominence formed by the bones 
of the ear ; the tympanic bulla 

bullate (bool'at) a. [L. bulla, water- 
bubble.] Blistered-like ; puckered 
like a savoy-cabbage leaf (oot.). 

bunodont (bu'nodont) a. [Gk. bounos, 
mound ; odous, tooth.] Having 
molar teeth with low conical cusps 

bunoid (bu'noid) a. [Gk. bounos, 
mound.] Appl. cusps of cheek- 
teeth, low and conical (zoo/.). 

bunolophodont (bu'nolof'6d6nt) a. 
[Gk. bounos, mound ; lophos, crest ; 
odous, tooth.] Between bunodont 
and lophodont in structure, appl. 
cheek-teeth (zoo!.). 

bunoselenodont (bu'nosSle'nodSnt) a. 
[Gk. bounos, mound ; selene, moon ; 
odous, tooth.] Having the internal 
cusps bunoid, the external selenoid ; 
appl. cheek-teeth (zoo/.). 

bursa (bur'sa) n. [L. bursa, purse.] 
A sac-like cavity ; a sac rilled with 
viscid fluid at joints to prevent 
friction (anat.). 

bursa copulatrix, a genital pouch 


in Lepidoptera and Turbellarians 

bursicule (buYsikiil) n. [L. dim. of 
bursa, purse.] A small sac (zoo/.). 

butyrinase (bu'tlrinas) n. [L. butyrutn, 
butter.] An enzyme occurring in 
blood serum (phys.}. 

byssal (bls'al) a. [Gk. byssos, fine 
flax.] Pert, the byssus (zoo/.). 

byssus (bis'us) n. [Gk. byssos, fine 
flax.] The tuft of strong filaments, 
secreted in a gland of certain bi- 
valve Molluscs, by which they attach 
themselves to one another and to 
rocks, etc. (zoo/.) 

cachalots (kash'alot) n. [Sp. cacha- 
lote, the sperm whale.] The sperm 
whale (zoo/.). 

cadophore (kad'ofor) n. [Gk. kados, 
urn ; pherein, to bear.J A dorsal 
process in certain of the free- 
swimming Tunicates on which the 
buds are borne (zoo/.). 

caducibranchiate (kadu'sibranglclat) 
a. [L. caducus, from cadere, to 
fall; Gk. brangchia, gills.] With 
temporary gills (zoo/.). 

caducous (kadu'kus) a. [L. caducus, 
from cadere, to fall.] Pert, parts 
that fall off very early, e.g. calyx 

caecum (se'kum) n. [L. caecus, blind.] 
A blind diverticulum or pouch from 
some part of the alimentary canal 
(anat., zoo/.). 

Caenogaea (se'nqje'a) n. [Gk. kainos, 
recent;^, land.] Azoogeographical 
region under which is included the 
Nearctic, Palearctic, and Oriental 
regions; cf. Bogaea; also spelt 

caenogenesis (se'nqje'n'e'sTs) n. [Gk. 
kainos, recent ; genesis, birth.] 
The non-phylogenetic processes in 
the development of any individual 

Caenozoic (senozo'ik) a. [Gk. kainos, 
recent ; zoe, life.] Pert, the geo- 
logical era from Mesozoic to recent 
times ; also Calnozolc. 

caespitose (seVpTtos) a. [L. caexpus. 




turf.] Pert, turf; having low, 
closely matted stems (bot). 

calamistrum (karamis'trum) n. [L. 
calamistrum, a curling iron.] A 
comb-like structure on the hind 
limbs of certain spiders (zool.). 

calamus (kal'amus) n. [L. calamus, 
a reed.J The quill of a feather 

calcaneum (kalka'neum) n. [L. calx, 
heel.] The heel ; a large bone in 
the tarsus which forms the heel and 
represents the fibulare in lower 
forms ; a process on the meta- 
tarsus of birds (anat., zool). 

calcar (kal'kar) n. [L. calcar, a spur.] 
A hollow prolongation or tube at 
the base of a sepal or petal (hot.} ; 
a spur-like process on the leg or 
wing of birds which is not a digit ; 
a tibial spine in insects ; a process 
of the calcaneum which supports 
the web between the leg and tail 
in bats ; the pre-hallux of a frog 

calcareous (kalka'reus) a. [L. cal- 
carius, limy.] Growing on soil 
derived from decomposition of cal- 
careous rocks (hot.). 

calcariform (kalkar'iform) a. [L. 
calcar, a spur ; forma, shape.] 

calcarine (kal'karln) a. [L. calcar, a 
spur.] Pert, the hippocampus 
minor (anat.). 

calclferous (kalsif'erus) a. [L. calx, 
lime ; ferre, to carry.] Containing 
lime (biol). 

calcification (kalslfika'shun) n. [L. 
calx, lime ; facere, to make.] The 
deposition of lime salts in a tissue 

calcigerous (kalsij'erus) a. [L. calx, 
lime ; gerere, to carry.] Producing 
or containing lime salts (biol). 

calcivorous (kalsiv'orus) a. [L. calx, 
lime ; vorare, to devour.] Appl. 
plants which live on limestone 

calicle, see calycle. 

callosal (kalo'sal) a. [L. callosus, 
hard.] Pert, the corpus callosum 

callosities (kalos'itiz) n. plu. [L. cal- 
lositas, hardness.] Hardened and 
thickened areas on the skin, or on 
the bark of a plant, which often 

project beyond the general surface 
(bot., zool.). 

callus (kal'us) n. [L. callus, callous 
skin.] A growth of shell - like 
material within the umbilicus of a 
shell (zool.) ; the soft tissue that 
forms over the cut or damaged 
surface of any stem or branch 

caloricity (kalb'rls'iti) n. [L. calere, 
to be warm.] In animals, the 
power of developing and maintain- 
ing a certain degree of heat (phys.). 

caltrop (kal'trop) n. [A.S. coltraeppe- 
a sort of thistle.] A sponge spicule 
with four rays so disposed that any 
three being on the ground the fourth 
projects vertically upwards (zool). 
Also spelt calthrops. 

calvarium (kalva'rium) n. [L. calvus, 
bald.] The dome or upper portion 
of the skull (anat.). 

calycanthemy (kal'ikan'themi) n, 
[Gk. kalyx, a calyx ; anthemon, a 
flower.] Abnormal development 
of various parts of the calyx into 
petals (bot). 

calyciflorous (kal'isiflo'rus) a. [L. 
calyx, a calyx ; flos, a flower.] Appl. 
flowers in which stamens and petals 
are adnate to the calyx (bot). 

calyciform (kalis'iform) a. [L. calyx, 
a calyx ; forma, shape.] .Calyx-like 
in shape (bot). 

calycine (kal'Ism) a. [L. calyx, a 
calyx.] Pert, a calyx ; cup-like 
(bot., zool). 

calycle (kal'ikl) n. [L. calyculus, a 
little calyx.] An epicalyx (bot) ; 
any of the cup-shaped cavities in 
a coral ; a theca in a Hydroid 

calyptoblastic (kalip'toblas'tik) a. 
[Gk. kalyptos, hidden ; blastos, a 
bud.] Pert. Hydroids in which the 
reproductive persons or gonophores 
are enclosed in a gonotheca (zool) 

calyptobranchiate (kalTp'tobrang'klat) 
a. [Gk. kalyptos, hidden ; brangchia, 
gills.] With gills not visible from 
the exterior (zool.). 

calyptra (kalip'tra) n. [Gk. kalyptra, 
a covering.] The cap-like remains 
of the archegonium found surround- 
ing the apex of the capsule in mosses 

calyptrogen (kaltp'trojen) n. [Gk, 




kalyptra, a cap ; genesis, birth.] 
The special layer of cells lying 
at the apex of a growing root and 
giving origin to the root-cap (hot.}. 

calyx (ka'llks) ., calyces (ka'lisez) 
plu. [L. calyx, a calyx.] The outer 
whorl of floral leaves (hot.) ; the 
cup-like portion of the pelvis of 
the kidney (anat.} ; the theca of 
certain Hydroids, the cup-like body 
of the Crinoids (zool.}. 

cambiform (kam'biform) a. [L. 
cambium, change ; forma, shape.] 
Essentially similar to cambium 
cells (dot.). 

cambiogenetic (kam'bioje'ne't'ik) a. 
[L. cambium, change ; genesis, 
birth.] Appl. cells which produce 
cambium (bot.}. 

cambium (kam'bium) n. [L. cambium, 
change.] The soft tissue from 
which new root and bark are 
formed in the stems and roots of 
shrubs and trees (bot.}. 

Cambrian (kam'brTan) a. [L. Cambria, 
Wales.] Pert, the earliest division 
of the Palaeozoic era (pal,}. 

cameration (kamfira'shun) n. [L. 
cameratio, vaulting.] Division into 
alargenumberof separate chambers 

camerostome (kam'grostom') n. [L. 
camera, a chamber ; stoma, a 
mouth.] The hollowed-out under 
surface of the " hood " of certain 
Trogulidae (zool.}. 

camptodrome (kamp'todrom) a. [Gk. 
kampios, flexible ; dromos, a course.] 
Pert, leaf venation in which the 
secondary veins bend forward and 
anastomose before reaching the 
margin (bot.}. 

campylospermous (kam'pilospeYmus) 
a. [Gk. kampylos, curved ; sperma, 
a seed.] Appl. seeds with a groove 
along the inner face (bot.}. 

campylotropous (kam'pilot'ropus) a. 
[Gk. kampylos, curved ; trope, a 
turning.] Pert, ovules in which 
the nucellus and embryo-sac are 
bent so that the micropyle points 
almost back to the placenta (bot.}. 

canal (kanal') n. [L. canalis, a 
channel.] A duct ; a tubular 
passage formed in or by some 
tissue ; a groove in the hard or 
soft parts of various animals ; a 

passage or groove found in the 
tissues of numerous plants. 

canalicular (kanallk'ular) a. [L. 
canalicuhis, a small channel.] Pert. 

canaliculus (kanalik'ulus) n. [L. 
canaliculus, a small channel.] 
Canaliculi (ptu.) are small canals 
connecting the lacunae with one 
another or with the Haversian 
canals in bone ; small channels 
for the passage of nerves through 
various bones (anat.}. 

canaliform(kanarrf6rm)a. [L. canalis, 
a canal ; forma, shape.] Canal-like 
(biol., anat.}. 

cancellous (kan'sglus) a. [L. can- 
cellosus, chambered.] Consisting 
of slender fibres and lamellae, 
which join to form a reticular 
structure ; appl. the inner, more 
spongy, portion of bony tissue 

cancrisocial (kang'kriso'shal) a. [L. 
cancer, a crab ; socius, an ally.] 
Appl. animals which live on the 
shell of, or are commensal with, 
a crab (zool.}. 

canine (kanln', ka'nln) n. [L. cants, 
a dog.] The tooth next to the 
incisors; a., pert, the canine tooth, 
or to a ridge or groove on the 
surface of the superior maxillary 
(anat., zool.}. 

cannon bone (kan'on bon) n. [L. 
canna, a reed.] The bone support- 
ing the limb from hock to fetlock, 
the enlarged and fused metacarpals 
or metatarsals ; in birds the tarso- 
metatarsus (zool.}. 

canthus (kan'thus) n. [Gk. kanthelia, 
a pack-saddle.] The angle where 
the upper and lower eyelids meet 

capillary (kaptrari) a. [L. capillus, 
hair.] Minute ; hair-like ; n. one 
of the minute thin-walled vessels 
which form networks in various 
parts of the body, e.g. blood, lymph, 
or biliary capillaries (anat.}. 

capillitium (kap'ilTt'ium, kap'Ilish'ium) 
n. [L. capillus, hair.] A peculiar 
protoplasmic network of filaments 
among which the spores are found 
in the sporangia of certain Fungi 

capitate (kap'itat) a. [L. caput, the 




head.] Enlarged or swollen at 
the tip (zool.) ; gathered together 
into a mass at the apex, as in some 
inflorescences (dot.). 

capitellum (kap'iteTum) n. [L. caput, 
the head.] An articulatory pro- 
tuberance at the end of a bone, 
e.g. on the humerus for the articula- 
tion of the radius (anat.). 

capitulum (kaplt'ulum) n. [L. caput, 
the head.] A knob-like swelling 
at the end of a bone (anat.) ; the 
part of the body of a Cirripede 
enclosed in the mantle as opposed 
to the peduncle ; the swollen end 
of a hair or tentacle ; the enlarged 
end of an insect proboscis ; the 
exsert part of the head in ticks 
(zool.) ; an inflorescence of sessile 
flowers or florets crowded together 
on a receptacle and usually sur- 
rounded by an involucre (hot.). 

capreolate (k&pre'olat, k&p'reolat) a. 
[L. capreolus, a tendril.] Supplied 
with tendrils (dot.). 

capsule (kap'sul) n. [L. capsula, a 
little box.] A sac-like membrane 
enclosing either the whole or a 
part of an organ (anat., zool.) ; any 
closed box-like vessel containing 
spores, seeds, or fruits (dot.). 

capsuliferous (kap'sulif'grus) a. [L. 
capsula, a little box ;ferre, to carry.] 
With or forming a capsule (biol., 

capsuligerous, capsulogenous, cap- 

caput (kap'ut) n. [L. caput, the head.] 
Head ; a knob-like swelling at the 
apex (anat., zool.). 

carapace (kaYapas) n. [S p. carapacho, 
covering.] A shield covering the 
whole or part of the back of certain 
animals, it may be chitinous or 
bony (zool.). 

carbohydrates (kar'bohl'drats) n. plu. 
[L. cardo, coal ; Gk. hydros, water.] 
Compounds of carbon, hydrogen, 
and oxygen, generally speaking alde- 
hyde or ketone alcohols, or con- 
densation products thereof (dial.). 

carbon dioxide (kar'b6n dlok'sid) n. 
[L. cardo, coal ; di, two ; Gk. oxys, 
sharp.] Carbonic acid gas ; a heavy, 
colourless gas produced by the de- 
composition of organic substances 

carboniferous (kar'bonif'e'rus) a. [L. 
cardo, coal ; ferre, to carry.] Pert. 
the entire period of the coal 
measures, or fossils found in these 
strata (pal.). 

carcerule (kar'sSrool) n. [L. career, 
a prison.] A superior, dry, many- 
celled fruit, with indehiscent one- 
or few-seeded carpels cohering by 
their united styles to a central axis 

carcinology (kar'sinol'ojl) n. [Gk. 
karkinos, a crab ; logos, discourse.] 
The study of the group of animals 
known as Crustacea (zool.). 

cardiac (kaYdiak) a. [Gk. kardia, the 
heart.] Pert, near or supplying 
the heart ; appl. sinus, artery, etc. 

cardiac impulse, the motion caused 
by the rapid increase in the tension 
of the ventricle (phys.). 

cardinal (kaVdmal) a. [L. cardo, a 
hinge.] Pert, the hinge of a bivalve 
shell, or to the cardo of many 
insects (zool.). 

cardinal sinuses and veins, veins 
uniting in Cuvier's duct, persistent 
in most fishes, embryonic in other 
vertebrates (zool.). 

cardo (kar'do) n. [L. cardo, a hinge.] 
The hinge of a bivalve shell ; the 
basal joint of the maxilla in insects 

carina (karl'na, kare'na) n. [L. carina, 
keel.] A keel-like ridge on certain 
bones, as the breast-bone of birds ; 
the median dorsal plate of a barnacle 
(zool) ; the portion of a leguminous 
flower in which the stamens and 
pistils are contained ; a ridge on 
the bracts of certain grasses (dot.). 

carinate (kar'Inat) a. [L. carina, a 
keel.] Having a ridge or keel 

cariniform (karm'if6rm) a. [L. carina, 
a keel ; forma, shape.] Keel- 
shaped (dial.). 

carnassial (karnas'ial) a. [L. caro, 
flesh.] Pert, cutting teeth of carni- 
vores, the fourth premolar above 
and the first molar below, in the 
upper the protocone is reduced, in 
the lower the metaconid (zool.). 

carnivorous (karniv'orus) a. [L. caro, 
flesh ; vorare, to devour.] Flesh- 
eating ; appl. carnivores (zool.), and 




certain plants which feed on the 
proteids of entrapped insects (dot.}. 

carotid (karSt'Id) a. [Gk. karos, heavy 
sleep.] Pert, the chief arteries in 
the neck (anat., zool.). 

carpale (karpal'a, karpa'le) n. [L. 
carpus, wrist.] One of the bones 
of the wrist (anat.). 

carpels (kar'pglz) n.plu. [Gk. karpos, 
fruit.] The modified leaves which 
carry the megasporangia (bot.). 

carpocerite (karp5s'6rit) n. [L. carpus, 
wrist ; Gk. keras, horn.] The fifth 
joint of the antenna in certain 
Crustaceans (zool.). 

carpogenous (karpoj'finus) a. [Gk. 
karpos, fruit ; genos, birth.] Appl. 
those cells in red Algae which form 
the carpogonium (hot.). 

carpogonium (kar'pogo'nium) n. [Gk. 
karpos, fruit ; gignesthai, to be 
born.] The lower portion of the 
procarp, in some Thallophytes, 
which contains the female nucleus 

carpolith (kar'pollth) n. [Gk. karpos, 
fruit ; lithos, stone.] A fossil fruit 

carpometacarpus (kar'pome'takar'pus) 
n. [L. carpus, wrist ; Gk. meta, 
after.] The portion of the wing 
skeleton of a bird formed by the 
fusion of the carpal and meta- 
carpal bones (zool.). 

carpophagous (karpof'agus) a. [Gk. 
karpos, fruit ; phagein, to eat.] 
Feeding on fruit (zool.). 

carpophore (kar'pofor) n. [Gk. karpos, 
fruit ; pherein, to bear.] The part 
of the axis of a flower situate 
between or above the carpels, and to 
which the carpels are attached (bot.). 

carpophyte (kar'poflt) n. [Gk. karpos, 
fruit ; phyton, a plant.] Such of the 
Thallophytes as form sporocarps 

carpopodite (karpop'odlt) n. [L. 
carpus, wrist ; Gk. pous, a foot.] 
The third joint in the walking leg 
of certain Crustaceans (zool.). 

carposperm (kar'pospeYm) n. [Gk. 
karpos, fruit ; sperma, a seed.] The 
oosphere in certain Thallophytes 
after fertilization (bot.). 
carposporangium (kir'posporSn'jTum) 
n. [Gk. karpos, fruit ; spares, a 
seed ; anggeion, a vessel.] The 

terminal cells of the filaments that 
are developed from the fertilized 
carpogonium in some Thallophytes 

carpospore (kar'pospor) n. [Gk. 
karpos, fruit ; scores, seed.] A 
spore of those formed at the end 
of the filaments which are developed 
from the carpogonium (bot.). 
carpus (kar'pus) n. [L. carpus, wrist.] 
The wrist ; the region of the fore- 
limb between forearm and meta- 
carpus (anat., zool.). 
cartilage (kar'tilaj) n. [L. cartilage, 
cartilage.] Gristle ; a translucent, 
bluish-white tissue, firm and at the 
same time elastic, found for the 
most part in connection with bones 
of the skeleton, most of which are 
in the embryo represented by carti- 
lage (anat., zool.). 

caruncle (karung'kl) n. [L. caruncula, 
a small piece of flesh.] A naked, 
fleshy excrescence (anat.). ; a fleshy 
outgrowth on the heads of certain 
birds, and on certain caterpillars ; 
a little horny elevation at the end 
of the beak of embryo chicks ; the 
sucking-disc on the tarsi of certain 
mites (zool.)-, one of outgrowths from 
various regions of the testa of a 
seed, arising after fertilization (bof.). 

caryo, see karyo-. 

caryopsis (kar^p'sls) n. [Gk. kar- 
yon, a nut ; opsis, appearance.] A 
superior, one-celled, one-seeded, 
indehiscent fruit with a thin dry 
membranous pericarp inseparably 
united with the seed (bot.). 

casein (ka'seln) n. [L. caseus, cheese.] 
A nucleoalbumin proteid of milk, 
separated by the action of rennet 

cassideous (kasid'eus) a. [L. cassis, a 
helmet.] Helmet-like (bot.). 

caste (kast) n. [L. castus, pure.] One 
of the distinct forms found among 
certain social insects (zool.). 

castrate (kas'trat) a. [L. castrare, to 
castrate.] Pert, flowers from which 
the androecium has been removed 

cata-, see kata-. 

catalysis (katal'fsTs) . [Gk. kata, 
down ; lysis, a loosing.] The 
acceleration or retardation of a 
reaction due" to the presence of a 




substance which apparently remains 
unchanged, e.g. enzymes (biol.). 

cataphyllary (kat'afil'ari) a. [Gk. 
kata, down ; phyllon, a leaf.] Appl. 
rudimentary or scale-like leaves 
which act as the covering of buds, 
etc. (dot.). 

catenpid (kat'enoid) a. [L. catena, a 
chain.] Chain-like ; appl. certain 
protozoan colonies (zool.). 

catenulate (katSn'ulat) a. [L. catena, 
a chain.] Chain-like ; appl. colonies 
of bacteria, colour-markings on 
butterfly wings, shells, etc. (zool.). 

caterpillar (kat'erpll'ar) n. [L.L. 
cattus, a cat ; L. pilosus, hairy.] 
The young worm-like larva of many 
insects (zool.). 

catkin (kat'kin) n. [A.S. catkin, a 
little cat] A kind of spike with 
unisexual flowers and pendulous 
rachis (bot.). 

cauda (ko'da) n. [L. cauda, a tail.] 
A tail, or tail-like appendage ; the 
posterior part of an organ, e.g. 
cauda equina, cauda epididymis 
(anat.) ; a tube at the posterior end 
of the abdomen of certain insects 
suggesting the presence of an 
eleventh segment (zool.). 

caudal (ko'dal) a. [L. cauda, a tail.] 
Of or pert, a tail, e.g. caudal fin, the 
terminal fin of a fish (sool.). 

caudate (ko'dat) a. [L. cauda, a tail.] 
Having a tail, e.g. caudate nucleus, 
a mass of gray matter in the corpus 
striatum (anat.). 

caudatolenticular (koda'tolgntik'ular) 
a. [L. cauda, a tail ; lens, a lentil.] 
Appl. the caudate and lenticular 
nuclei of the corpus striatum (anat.). 

caudex (ko'dSks) n. [L. caudex, a 
dry stump.] The axis or stem of 
a woody plant (bot.). 

caudicle (k6'dikl) n. [Dim. of L. 
cauda, a tail] The stalks of the 
pollinia in orchids (bot.). 

caul (k61) n. [M.E. calle, a covering.] 
An enclosing membrane (anat.). 

caulescent (kolfis'Snt) a. [L. caulis, 
a stalk.] With leaf-bearing stem 
above ground (bot.). 

caulicolous (k61ik'olus) a. [L. caulis, 
a stalk ; colere, to inhabit.] Appl. 
Fungi which grow on the stems of 
other plants (bot.). 

cauliform (k61'If6rm) a. [L. caulis, a 

stalk ; forma, shape.] Stem-like 

cauligenous (kolij'enus) a. [Gk. 
kattlos, a stem ; genos, birth.] 
Borne on the stem (bot.). 

cauline (ko'lln) a. [L. caulis, a stalk.] 
Appl. leaves growing on the upper 
portion of a stem ; appl. vascular 
bundles not passing into the leaves 

caulocarpous (ko'lokar'pus) a. [Gk. 
kaulos, a stem ; karpos, a fruit.] 
With fruit-bearing stem (bot.). 

caulome (ko'lom) n. [Gk. kaulos, a 
stem.] The stem structure of a 
plant as a whole (bot.). 

cavernosus (kav'erno'sus) a. [L. 
cavernosus, chambered.] Full of 
cavities ; hollow, or resembling a 
hollow ; appl. tissue, nerve, arteries 

cavicorn (kav'ikorn) a. [L. cavus, 
hollow ; cornu, horn.] Hollow- 
horned ; appl. certain of the 
ruminants (zool.). 

cavity (kav'iti) n. [L. cavus, hollow.] 
A hollow, enclosed or cup-shaped ; 
e.g. amniotic, glenoid cavity (anat.). 

cavum (ka'vum) n. [L. cavus, hollow.] 
The lower division of the concha 
caused by the origin of the helix ; 
any hollow or chamber in which an 
organ or part thereof lies (anat.). 

cell (sel) n. [L. cella, a compartment.] 
A small cavity or hollow ; a unit 
mass of protoplasm, usually con- 
taining a nucleus (biol.). 

cellifugal (selif'ugal) a. [L. cella, a 
cell ; fugere, to flee.] Moving 
away from a cell (phys.). 

cellipetal (selip'gtal) a. [L. cella, a 
cell ; petere, to seek.] Moving 
towards a cell (phys.). 

cell lineage, the derivation of a 
tissue or part from a definite blasto- 
mere of the embryo (biol.). 

cell membrane,- a membranous cell- 
wall (biol.). 

cell organ, a part of a cell having a 
special function, as a centrosome 

cell plate, the equatorial thickening 
of the spindle fibres from which the 
partition wall arises during the 
division of plant cells (cyt.). 

cell sap, the more fluid ground sub- 
stance of the cell or nucleus (cyt.). 




cellular (sefular) a. [L. cellula, a 
small cell.] Pert, or consisting of 
cells (biol.). 

cellulose (seTulos) . [L. cellula, a 
small cell.] A carbohydrate form- 
ing the main part of the cell walls 
of plants, also found in the tests of 
tunicates (biol.). 

cell-wall, the investing portion of 
a cell, which may be extremely 
delicate, or may be strong and 
thick as in plants (cyt.). 

cement (sement') n. [L. caementum, 
mortar.] A substance chemically 
and physically allied to bone, in- 
vesting the root, neck, and crowns 
of teeth (zool.). 

censer mechanism, the method of 
seed distribution by which seeds 
are jerked out from the fruit only 
by a high wind (dot.}. 

centradenia (seVtrade'nla) n. [L. 
centrum, a centre.] The name 
given to the type of siphonophore 
colony found in the Disconectae 

central (sgn'tral) a. [L. centrum, a 
centre.] Situated in the centre ; 
pert, a vertebral centrum (anat.). 

centrale (sentra'le, sfintral'a) n. [L. 
centrum, a centre.] A bone in the 
wrist or ankle situated between the 
proximal and distal rows (zool.). 

centric (sen'trik) a. [L. centrum, a 
centre.] AppL leaves which are 
cylindrical or terete (hot,}, 

centrifugal (sgntrif'ugal) a. [L. 
centrum, a centre ; fugere, to flee.] 
AppL compact cymose inflor- 
escences having the youngest 
flowers towards the outside (dot.) ; 
appl. nerves transmitting impres- 
sions from nerve centre to parts 
supplied by nerve (anat.). 

centrlole (sen'trlol) n. [L. centrum, 
a centre.] The central particle of 
the centrosome, in some authors ; 
in others, the centrosome itself 

centripetal (sgntrip'gtal) a. [L. 
centrum, a centre ; petere, to 
seek.] Appl. racemose inflor- 
escences having the youngest 
flowers at the apex (dot.) ; appl. 
nerves transmitting impressions 
from peripheral extremities to 
nerve centres (ana/.). 

centripetal canals, blind canals 
growing from the circular canal 
backwards towards the apex of 
the bell in certain Trachomedusae 

centrodesmose (sen'trodes'mos), cen- 
trodesmus (sgn'trodeVmus) n. [Gk. 
kentron, a centre ; desmos, a band.] 
The fibril or system of fibrils tempo- 
rarily connecting the two centro- 
somes (cyt.). 

centrodorsal (sfin'trodor'sal) a. [L. 
centrum, a centre ; dorsum, a back.] 
Appl. the plate in the middle of the 
aboral surface of unstalked Crinoids 

centrogenous (sentrqj'enus) a. [Gk. 
kentron, a centre ; genos, descent.] 
Appl. a skeleton of spicules which 
meet in a common centre and grow 
outwards (zool.). 

centrolecithal (sen'trolgs'ithal) a. 
[Gk. kentron, a centre ; lekithos, 
yolk.] Appl. an ovum with its 
yolk aggregated in the centre 

centroplasm (sgn'troplazm) n. [Gk. 
kentron, a centre ; plasma, some- 
thing moulded.] The substance of 
the centrosphere (cyt.). 

centrosome (sen'trosom) n. [Gk. 
kentron, a centre ; soma, body.] 
A cell-organ, being the centre of 
dynamic activity in mitosis, and 
consisting of centriole and attrac- 
tion-sphere (cyt.). 

centrosphere (sgn'trosfer) n. [Gk. 
kentron, a centre ; sphaira, a ball.] 
The central mass of the aster and 
centrosome ; the astrosphere ; the 
attraction sphere (cyt.). 

centrum (sen'trum) n. [L. centrum, 
a centre.] The main body of a 
vertebra, from which the neural and 
haemal arches arise (zool.). 

cephalanthium (ket'alan'thium, sef-) 
n. [Gk. kephale, a head ; anthos, 
a flower.] The capitulum in com- 
posite plants (&?/.). 

cephaletron (kgf'aletron, sfif-) n. [Gk. 
kephale, the head ; etron, the belly.] 
The anterior region of a Limulid 

cephalic (kefal'ik, sgf-) a. [Gk. kephale, 
the head.] Pert, the head ; in the 
head region. 

cephalia (kgf'alis, sgf-) . [Gk. 


kephale, the head.] The upper- 
most chamber of monaxonic Radio- 
larian shells (zool.). 
cephalization (kef'aliza'shun, s6f-) n. 
[Gk. kephale, the head.] Increasing 
importance of the anterior end in 
animal development (zool.). 

cephalont (kgf'alont, s6f-) n. [Gk. 
kephale, the head.] A sporozoan 
about to proceed to spore-formation 

cephalopoda (kgf'alopodz, sef-) n. plu. 
[Gk. kephale, the head ; pous, the 
foot.] Animals with muscular, 
sucker-bearing arms on the head 
region (zool.). 

cephalostegite (kef'alosteg'it, s6f-) n. 
[Gk. kephale, head ; siege, roof.] 
The anterior part of the cephalo- 
thoracic shield (zool.). 

cephalostyle (kefalostll, s6f-) n. [Gk. 
kephale, head ; stylos, a pillar.] 
The anterior end of the notochord 
enclosed in its sheath, in chondro- 
crania (zool.). 

cephalotheca (kgf'alothe'ka, sef-) n. 
[Gk. kephale, head ; theke, a case.] 
The head integument in the pupa 
of insects (zool.). 

cephalothorax (kef'alotho'raks, s6f-) 
n. [Gk. kephale, head ; thorax, 
breast.] The body-region formed 
by the fusion of head and thorax in 
Arachnids and Crustaceans (zool.). 

cephalotrocha (ket'alotrS'ka, sSf-) n. 
[Gk. kephale, head ; trochos, a 
wheel.] A Turbellarian larva with 
eight processes arranged round 
the mouth (zool.). 

cerata (keYata, sera'ta) n. plu. [Gk. 
keras, horn.] Lobes or leaf-like 
processes acting as gills on the 
back of nudibranch molluscs (zool.). 

ceratlum (sera'shium, sera'tium) n. 
[Gk. keration, little horn.] A siliqua 
without the replum (bot.). 

ceratohyal (keYatohi'al, ser-) n. [Gk. 
keras, horn ; hyoeides, Y-shaped.] 
The component of the hyoid arch 
next below the epihyal (zool.). 

cereal (seYkal) a. [Gk. kerkos, tail.] 
Pert, the tail (zool.). 

cercarla (sgrka'ria) n. [Gk. kerkos, 
tail.] A trematode larva with a 
slightly heart-shaped body and 
long tail (zool.). 

cercl (ser'ke, seYsl) n. plu. [Gk. 

46 CER- 

kerkos, tail.] Jointed appendages 
at the end of the abdomen in many 
Arthropods (zool.). 

cere (ser) n. [L. cera, wax.] A 
swollen fleshy patch at the proximal 
end of the bill in birds, on which 
the nostrils open. 

cerebellar (ser'ebeTar)a. [L. cerebrum, 
the brain.] Pert, the hind-brain 

cerebellum (ser'ebeTum) n. [L. 
cerebrum, the brain.] The fourth 
division of the brain arising from 
the differentiation of the anterior 
part of the third primary vesicle 

cerebral (ser'ebral) a. [L. cerebrum, 
the brain.] Pert, the brain ; pert. 
the anterior part of the brain or 
cerebral hemispheres. 

cerebrifugal (ser'ebrifu'gal) a. [L. 
cerebrum, the brain ; fugere, to 
flee.] Appl. nerve fibres which 
pass from brain to spinal cord 

cerebroganglion (ser'ebrogang'glion) 
n. [L. cerebrum, the brain ; Gk. 
ganglion, a swelling.] The brain, 
or supra-oesophageal ganglia of 
invertebrates (zool.). 

cerebropedal (ser'gbrope'dal) a. [L. 
cerebrum, the brain ; pes, a foot.] 
Appl. nerve strands connecting the 
cerebral and pedal ganglia in 
Molluscs (zool.). 

cerebrospinal (ser'ebrbspl'nal) a. [L. 
cerebrum, the brain ; spina, the 
spine.] Pert, brain and spinal 
cord (anat.}. 

cerebrovisceral (ser'ebrovis'eral) a. 
[L. cerebrum, the brain ; viscera, 
viscera.] Appl. the connective 
joining the cerebral and visceral 
ganglia in Molluscs (zool.). 

cerebrum (ser'ebrum) n. [L. cerebrum, 
the brain.] The fore-brain, or 
hemispheres, arising from the 
differentiation of the first primary 
vesicle (zool.). 

ceriferous (serlferus) a. [L. cera, 
wax ; ferre, to carry.] Appl. wax- 
producing organs (btol.). 

cernuous (seYnuus) a. [L. cernuus, 
with face turned downwards.] 
Drooping ; pendulous (bot.). 

ceroma (sero'ma) n. [Gk. keroma, 
ointment.] The cere of birds (zool.). 


cerous (se'nis) a. [L. cera, wax.] 
Appl. a structure resembling a 
cere (zool.). 

cerumen (sgroo'mgn) . [L. cera, 
wax.] The wax-like secretion 
from the ceruminous glands of 
the ear (phys.). 

cervical (servl'kal) a. [L. cervix, the 
neck.] Appl. structures connected 
with the neck, as nerves, bones, 
blood-vessels, also to the cervix or 
neck of an organ (anat., zool.). 

cervix (seYviks) n. [L. cervix, a 
neck.] The neck or narrow mouth 
of an organ, as cervix uteri (anat.). 

chaeta (ke'ta) n. [Gk. chaite, hair.] 
A seta or bristle of certain worms 

chaetiferous (ketlffirus) a. [Gk. 
chaite, hair ; L. ferre, to bear.] 
Bristle-bearing ; chaetigerous. 

chaetophorous (ketof'orus) a. [Gk. 
chaite, hair ; pherein, to bear.] 
Bristle-bearing ; appl. worms and 
certain insects (zool.). 

chaetotaxy (ke'totak'sl) n. [Gk. 
chaite, hair ; taxis, arrangement.] 
The bristle-patterns on an insect 

chalaza (kala'za) n. [Gk. chalaza, 
hail, tubercle.] One of the two 
spiral bands attaching the yolk to 
the membrane of a bird's egg 
(zool.) ; the base of the nucellus of 
an ovule from which the integu- 
ments arise (bot.). 

chalazogamy (kalazog'ami) n. [Gk. 
chalaza, hail, tubercle ; gamos, 
marriage.] Fertilization in which 
the pollen- tube pierces the chalaza 
of the ovule, instead of entering by 
the micropyle ; cf. porosramy (bot.). 

chalice (chal'is) n. [L. calix, calyx.] 
Appl. simple gland cells in the 
epithelia of the frog (zool.) ; any 
modified columnar epithelial gland 
cell (anat.). 

chalones (kal'onz) n. plu. [Gk. chali- 
nos, curb.] Substances which 
depress activity (phys.). 

channelled (chan'gld) a. [L. canalis, 
a canal.] Having grooves ; canal- 
iculate (bot.). 

chasmogamy (kazmog'amT) n. [Gk. 
chasma, opening ; gamos, marriage.] 
The opening of a mature flower to 
ensure fertilization (bot.). 


chasmophyte (kaz'mofit) n. [Gk. 
chasma, opening ; phyton, a plant.] 
A plant which grows in nooks and 
crannies of rocks (bot.). 

cheek (chek) n. [A.S. ce'oce, the 
cheek.] The fleshy wall of the 
mouth in mammals ; the side of 
the face ; in invertebrates the 
lateral portions of the head, as the 
fixed and free cheeks of Trilobites 
(zool., anat.). 

cheiropterygiuin (klrSptSrlj'Ium) n. 
[Gk. cheir, hand; pteryx, wing.] 
The pentadactyloid typical limb of 
higher vertebrates. 

chela (ke'la) n. [Gk. chele, claw.] 
The claw borne on certain limbs of 
Crustaceans and Arachnids (zool.). 

chelicerae (kelis'gre, -ra) n. plu. [Gk. 
chele, claw ; keras, horn.] Anterior 
chelate or sub-chelate appendages 
of Arachnids (zool.). 

cheliferous (kelif'erus) a. [Gk. chele, 
claw ; L. ferre, to bear.] Supplied 
with chelae or claws (zool.). 

cheliforin (ke'liform) a. [Gk. chele, 
claw ; L. forma, shape.] Claw-like ; 
appl. appendages (zool.). 

chelophores (keUforz) n. plu. [Gk. 
chele, claw ; pherein, to bear.] The 
first pair of appendages in the 
Pycnogons (zool.). 

chemoreflex (kgm'ore'flgks) n. [Gk. 
chemos, juice ; L. reflectere, to bend 
back.] A reflex caused by chemical 
stimulus (phys.). 

chemosynthesis (kSm'osin'thgsis) n. 
[Gk. chemos, juice ; syn, with ; 
tithenai, to place.] The building 
up of chemical compounds in plants 
by means of chemical reactions 

chemotaxis (kgm'otak'sis) . [Gk. 
chemos, juice ; taxis, arrangement.] 
The sensitiveness of cells or micro- 
organisms to chemical stimulus, 
which is either attractive or repel- 
lent, exhibiting respectively positive 
or negative chemotaxis (biol.). 

cheniotropism (ke'mot'ropizm) n. [Gk. 
chemos, juice ; trope, a turning.] 
Curvature of a plant towards or 
away from chemical stimuli (bot.) ; 
response to chemical stimulus (biol.). 

chevron (sheVron) a. [L. caper, 
a goat.] Appl. V-shaped bones 
articulating with the ventral surface 




of the spinal column in the caudal 
region of many vertebrates (zoo/.). 

chiasma (klaz'ma) n. [Gk. chiazein, 
to mark with a cross.] A decussa- 
tion, as optic chiasma (anat.). 

chlastoneural (klas'tonu'ral) a. [Gk. 
chiastos, diagonally arranged ; neu- 
ron, a nerve.] Appl. certain Gastro- 
pods in which the visceral nerve 
cords cross and form a figure 8 

chilaria (klla'ria) n. plu. [Gk. cheilos, 
lip.] A pair of processes between 
the sixth pair of appendages in 
Limulus (zool.). 

chilidium (killd'lum) n. [Gk. cheilos, 
lip.] A shelly plate covering the 
deltidial fissure in the dorsal valve 
of certain Brachiopods (zool.). 

chitln (kl'tln) n. [Gk. chiton, a tunic.] 
A carbohydrate derivative forming 
the skeletal substance in Arthropods 

chlamydate (klam'idat) a. [Gk. chla- 
mys, a cloak.] Supplied with a 
mantle (zool.). 

chlamydeous (klamid'eus) a. [Gk. 
chlamys, a cloak.] Pert, flower and 
envelope (bot.). 

chlamydospore (klam'idospor) n. [Gk. 
chlamys, cloak ; sporos, seed.] A 
thick-walled resting spore found in 
many Fungi, as yeast (bof.). 

chloragen (klo'rajen) a. [Gk. chloros, 
grass green ; genos, descent.] Appl. 
yellow cells found in connection 
with the alimentary canal of the 
earthworm, and other Annelids ; 
also chloragogen (zool.). 

chloranthy (kloran'thi) n. \G\a.chloros, 
grass green ; anthos, flower.] Re- 
version of floral leaves back to 
ordinary green leaves (bot.). 

chlorophyll (klo'rofil) n. [Gk. chloros, 
grass green ; phyllon, a leaf.] The 
green colouring matter found in 
plants and in some animals (biol.). 

chloroplast (klo'roplast) n. [Gk. 
chloros, grass green ; plastos, 
moulded.] A chlorophyll-carrying 
plastid (bot.). 

chloroplastid (klo'roplas'tid) n. [Gk. 
chloros, grass green ; plastos, 
moulded.] A minute granule or 
plastid containing chlorophyll, 
found in plant-cells exposed to light 

chlorosis (kloro'sls) ;/. [Gk. chloros, 
grass green.] A diseased condition 
in plants owing to lack of certain 
minerals, due mainly to want of 
light (bot.). 

chlorotic (klorot'ik) a. [Gk. chloros, 
grass green.] Appl. plants or 
organs of plants devoid of chloro- 
phyll (bot.). 

choana (ko'ana) n. [Gk. choane, 
funnel.] Any funnel-shaped open- 
ing (anat.). 

choanocyte (ko'anoslt) n. [Gk choane, 
funnel ; kytos, hollow.] A cell with 
a funnel-shaped rim or collar round 
the base of the flagellum (zool.). 

choanoid (ko'anoid) a. [Gk. choane, 
funnel ; eidos, like.] Funnel- 
shaped; appi.eye. muscle in Reptiles 

choanosome (ko'anosom) n. [Gk. 
choane, funnel ; soma, body.] In 
sponges, the inner layer with flagel- 
late cells (zool.). 

choledoch (kol'edok) a. [Gk. chole, 
bile ; dochos, containing.] Appl. 
common bile duct. 

choleic (kole'ik) a. [Gk. chole, bile.] 
Pert, acid contained in ox bile 

cholesterin (koles'terln) n. [Gk. chole, 
bile ; stereos, solid.] A white fatty 
alcohol found in nerve tissue, bile, 
yolk, and other animal substances 
(phys.). ^ 

choline (ko'lm, -en) n. [Gk. chole, 
bile.] A crystalline base found in 
plants and animals with composi- 
tion C 6 H 16 O 2 N (phys.). 

cholochrome (ko'lokrom) . [Gk. 
chole, bile ; chroma, colour.] A bile 
pigment (phys.). 

cholohaematin (ko'lohe'matm) n. [Gk. 
chole, bile ; haima, blood.] A pig- 
ment developed in the bile of 
ruminants after exposure to the air 

chondral (kon'dral) a. [Gk. chondros, 
cartilage.] Pert, cartilage (anat.). 

chondrification (kon'driflka'shun) n. 
[Gk. chondros, cartilage ; L. facere, 
to make.] Conversion into cartil- 
age (phys.). 

chondrigen (kon'drijen) n. [Gk. 
chondros, cartilage ; genos, descent.] 
The base matrix of all cartilaginous 
substance, a collagen (phys.). 




chondrin (kon'drin) n. [Gk. chondros, 
cartilage.] A gelatinous substance 
obtained from cartilage (phys.}. 

chondriosomes (kondrlosomz ) n. plu, 
[Gk. chondros, cartilage ; soma, 
body.] Permanent feebly refractive 
bodies found in cell protoplasm, 
which are probably combinations 
of fatty acids or of phosphate of 
albumen (biol.}. 

chondroblast (kon'droblast) n. [Gk. 
chondros, cartilage ; blastos, bud.] 
A cartilage-producing cell (phys.}. 

chondroclast (kon'droklast) n. [Gk. 
chondros, cartilage ; klastos, broken 
down.] A cell which breaks up or 
destroys cartilage cells (phys.}. 

chondrocranium (kon'drokra'nium) n, 
[Gk. chondros, cartilage ; kranion, 
skull.] The skull when in a car- 
tilaginous condition, either tem- 
porarily as in embryos, or per- 
manently as in some fishes (zoo!., 

chondrogenesis (kon'drojgn'esis) n. 
[Gk. chondros, cartilage ; genesis, 
descent.] The production or forma- 
tion of cartilage (phys.}. 

chondromucoid (kon'dromu'koid) n. 
[Gk. chondros, cartilage ; L. mucus, 
mucus ; Gk. eidos, form.] A whitish 
amorphous powder found in cartil- 
age (phys.}. 

chondrophore (kon'drofor) n. [Gk. 
chondros, cartilage ; pherein, to 
bear.] A structure which supports 
the inner hinge cartilage in a 
bivalve shell (zoo/.). 

chondroskeleton (kon'droskel'e'ton) n. 
[Gk. chondros, cartilage ; skeleton, 
a dried body.] A cartilaginous 
skeleton (zool.}. 

chondrosteous (kondros'teiis) a. [Gk. 
chondros, cartilage ; osteon, bone.] 
Having a cartilaginous skeleton 

chondrosteriial (kon'drosteYnal) a. 
[Gk. chondros, cartilage ; sternon, 
the breast.] Pert, rib cartilages 
and sternum (anat.}. 

chone (kon) n. [Gk. choane, a funnel.] 
A passage through the cortex of 
sponges with one or more external 
openings, and one internal open- 
ing provided with a sphincter 

chorda (kor'da) n. [Gk. chorde^ a 

string.] The notochord ; in plural, 
tendinous cords attached to the 
valves of the heart (anat.}. 

chordacentra (kor'dasgn'tra) n. plu. 
[Gk. chorde, a string ; L. centrum, 
centre.] Centra formed by the 
conversion of the chordal sheath 
into a number of rings (zool.}. 

chordate (kor'dat) a. [Gk. chorde, 
a string.] Having a notochord 

chordotonal (kor'doto'nal) a. [Gk. 
chorde, a string ; tonos, a tone.] 
Appl. rod-like or bristle-like struc- 
tures, auditory in nature, in various 
parts of the body of insects (zool.}. 

choriocapillaris (ko'riokapiraris, -kap'- 
ila'rls) n. [Gk. chorion, chorion ; L. 
capillaris, a capillary.] The inner- 
most vascular layer of the choroid 
coat of the eye (anat.}. 

chorioid, choroid. 

chorion (ko'rlon) n. [Gk. chorion, a 
skin.] An embryonic membrane 
external to and enclosing the 
amnion (emb.}. 

chorionlc (korion'ik) a. [Gk. chorion, 
a skin.] Pert, the chorion (emb.}. 

chorioretinal (ko'rioreYinal) a. [Gk. 
chorion, a skin ; L. retina, the 
retina.] Pert, choroid and reli ia 

choripetalous (ko'ripeYalus) a. [Gk. 
choris, separate ; petalon, a leaf.] 
Having separate petals (dot.}. 

choriphyllous (ko'rifil'us) a. [Gk. 
choris, separate ; phyllon, a leaf.] 
Having the perianth parts distinct 

chorisepalous (ko'risep'alus) a. [Gk. 
choris, separate ; sepalon, a sepal.] 
Having the sepals separate (hot.}. 

chorisis (ko'rlsts) . [Gk. choris, 
separate.] Increase in number of 
parts of a floral whorl due to 
division of its primary members ; 
duplication (bot.}. 

chorpid (ko'roid) a. [Gk. chorion, 
skin ; eidos, form.] Appl. delicate 
and highly vascular membranes ; 
n. the layer of the eye between 
retina and sclerotic (anat.}. 

choroidal (koroid'al) a. [Gk. chorion, 
skin ; eidos, form.] Pert, the 
choroid (anat.}. 

chorology (korol'qjl) n. [Gk. choros, 
place ; logos, discourse.] The 




science which deals with the dis- 
tribution of organs (biol.). 

chromaffln (kromafin) a. [Gk. 
chroma, colour ; L. affinis, re- 
lated.] AppL cells forming the 
medullary parts of the suprarenal 
bodies, on account of their yellow 
colour after treatment with chromic 
salts ; chromophil (phys.). 

chromatic (kromat'lk). [Gk. chroma, 
colour.] Colourable by means of 
staining reagents (biol.). 

chromatic sphere, the sphere formed 
by coalescence of chromosomes after 
the anaphase in mitosis (bot.). 

chromatin (kro'matln) n. [Gk. chroma, 
colour.] A substance in the nucleus 
which contains nucleic acid proteids 
and stains with basic dyes (biol?). 

chromatogen organ, a brownish 
lobed body, the axial organ of 
certain Echinoderms (zool.). 

chromatoid grains, readily stainable 
grains in cell-protoplasm, probably 
of an albuminous nature (cyt.). 

chromatolysis (kro'matol'Ms) n. [Gk. 
chroma, colour ; lyein, to break up.] 
Disintegration and final disappear- 
ance of the chromatin in injured 
nerve-cells (phys.). 

chromatophore (kro'matofor) n. [Gk. 
chroma, colour ; pherein, to bear.] 
The general term appl. coloured 
plastids of plants and animals 
(cyt.) ; a pigment cell, which under 
control of the sympathetic nervous 
system can be altered in shape to 
produce a colour change (zoo!.). 

chromatoplasm (kro'matd'plazm) n. 
[Gk. chroma, colour ; plasma, some- 
thing moulded.] The colour or 
pigment matter in cells (cyt.}. 

chromatospherite (kro'matdsfer'lt) n. 
[Gk. chroma, colour ; sphaira, a 
globe.] A nucleolus, which see (cyt.). 

chromidia (kro'mld'ia) n. plu. [Gk. 
chroma^ colour.] Extra - nuclear 
particles of chromatin (cyt.). 

chromidiosomes (kromid'fosomz') n. 
plu. [Gk. chroma, colour ; soma, 
body.] The smallest chromatin 
particles of which the chromidial 
mass is made up (cyt.). 

chromoblast (kro'moblast) n. [Gk. 
chroma, colour ; blastos, a bud.] 
An embryonic cell giving rise to a 
pigment cell (biol.}. 

chromogen (kro'mojfin) n. [Gk. 
chroma, colour; genos, birth.] The 
material in plants which will de- 
velop into colouring matter (bot.). 

chromogenic (kro'mojgn'ik) a. [Gk. 
chroma, colour ; genos, birth.] 
Colour - producing ; appl. organ- 
isms, as bacteria (bot.). 

chromomere (kro'momer) n. [Gk. 
chroma, colour ; meros, part.] One 
of the chromatin granules of which 
a chromosome is formed, and which 
corresponds to an id (cyt.). 

chromophanes (kro'mofanz) n. plu. 
[Gk. chroma, colour ; phainein, to 
show.] Red, yellow, and green oil 
globules found in the retina of 
birds, reptiles, fishes, and mar- 
supials (zool.). 

chromophil (kro'mofil) a. [Gk. 
chroma, colour ; philein, to love.] 
Chromaffin, which see. 

chromophilous (kromof iltis) a. [Gk. 
chroma, colour ; philos, loving.] 
Staining readily (biol.). 

chromophore (kro'mofor) n. [Gk. 
chroma, colour ; pherein, to bear.] 
Any substance to whose presence 
colour in a compound is due 

chromoplast (kro'moplast) n. [Gk. 
chroma, colour ; plastos, moulded], 
also chromoplastid. A coloured 
plastid or pigment body other than 
a chloroplast (biol.). 

chromoproteid (kro'mopro'teid) n. 
[Gk. chroma, colour ; protos, first.] 
Substance formed by combination 
of a proteid and a pigment (phys.). 

chromosome (kro'mosom) n. [Gk. 
chroma, colour ; soma, body.] One 
of the deeply staining bodies, the 
number of which is definite for the 
cells of a species, into which the 
chromatin resolves itself during 
karyokinesis (cyt.). 

chrysalis (kris'alis) n. [Gk. chrysos, 
gold.] The pupa stage of certain 
insects (zool.). 

chrysocarpous (kris'okar'pus) a. [Gk. 
chrysos, gold ; karpos, fruit.] With 
golden fruit (bot.). 

chrysophyll (krls'of il) n. [Gk. chrysos, 
gold ; phyllon, a leaf.] A yellow 
colouring matter in plants, a de- 
composition product of chlorophyll 




chylaceous (kila'shus) a. [Gk. chylos, 
juice.] Of a chyle-like nature ; pert, 
chyle (phys.). 

chyle (kil) n. [Gk. chylos, juice.] 
Lymph containing globules of 
emulsified fat found in the lacteals 
during digestion (phys.). 

chylifaction (kl'lifak'shun) n. [Gk. 
chylos, juice ; L. facere, to make], 
also chylification. The formation of 
chyle (Phys.). 

chyliferous (kllif'erus) a. [Gk. chylos, 
juice ; L. ferre, to carry.] Chyle- 
conducting ; appl. tubes or vessels 

chyliflc (klllf'ik) a. [Gk. chylos, juice ; 
L. facere, to make.] Chyle-pro- 
ducing ; appl. the true stomach of 
insects (zool.). 

chylocaulous (klldcol'us) a. [Gk. 
chylos, juice ; L. caulis, a stem.] 
With fleshy stems (bot.). 

chylocyst (kl'losist) n. [Gk. chylos, 
juice ; kystis, a bladder.] The 
chyle receptacle (anat.). 

chylophyllous (kl'lofil'us) a. [Gk. 
chylos, juice ; phyllon, a leaf.] 
With fleshy leaves ; appl. certain 
desert plants (bot.). 

chylopoiesis (kl'lopoie'sis) n. [Gk. 
chylos, juice ; poiein, to produce.] 
The production of chyle (phys.). 

chyme (kim) n. [Gk. chymos, juice.] 
The partially digested food after 
leaving the stomach (phys.). 

chymification (ki'miflka'shun) n. 
[Gk. chymos, juice ; L. facere, to 
make.] The process of converting 
food into chyme (phys.). 

cicatricial tissue, newly - formed 
fibrillar connective tissue which 
closes and draws together wounds 

cicatrlcle (sik'atrik'l), cicatricula 
(sik'atrik'ula) n. [L. cicatrix, a 
wound.] The blastoderm in bird 
and reptile eggs (emb.) ; a small 
scar in the place of previous attach- 
ment of an organ (zoo/.} ; the ^mark 
left after the healing up of a wound 
in plants (bot.). 

cicatrix (sik'atriks, slka'triks) n. [L. 
cicatrix, a wound.] Cicatricle, 
which see. 

ciclnnal (slsm'al) a. [Gk. kikinnos, 
a curled lock.] Appl. uniparous 
cymose branching in which the 

daughter axes are developed right 
and left alternately (bot.). 

cilia (sil'ia) n. plu. [L. cilium, an 
eyelid.] Hairlike vibratile out- 
growths of the ectoderm or pro- 
cesses found in many cells (biol.) ; 
barbicels of a feather (zool.) ; 
marginal hairlike processes (bot.} ; 
eyelashes (anaf.). 

ciliary (sil'lari) a. [L. cilium, an 
eyelid.] Pert, cilia ; appl. certain 
structures in the eyeball (anaf., 

ciliate (sil'iat) a. [L. cilium, an eye- 
lid.] Provided with cilia (biol.}. 

ciliated epithelium, an epithelium 
found lining various passages, 
usually with columnar cells, the 
free edge of each of which has a 
bunch of fine tapering vibratile 
hairlike outgrowths (zool., phys.~). 

ciliograde (sil'iograd) a. [L. cilium, 
an eyelid ; gradus, a step.] Pro- 
gressing by ciliary movement (zool.). 

ciliospore (sil'iospor) n. [L. cilium, 
an eyelid ; Gk. sporos, a seed.] A 
protozoan swarm-spore with a coat 
of cilia (zool.). 

cilium (sil'mm) n. [L. cilium, an 
eyelid.] Sing, of cilia, which see. 

cinchonin (sm'konin) n. [Named after 
a Countess Chinchon.] A white 
alkaloid found in various types of 
Rubiaceae (bot.). 

cincinnus (sinsin'us) n. [Gk. kikinnos, 
a curled lock.] A scorpioid cyme 

cinclides (sing'klldez) n. plu. [Gk. 
kingklis, a latticed gate.] Perfora- 
tions in the body wall of certain 
Anthozoa for the extrusion of acontia 

cinclis (sing'klis) n. [Gk. kingklis, a 
latticed gate.] Sing, of cinclides, 
which see. 

cingulate (sing'gulat) a. [L. cin- 
gulum, a girdle.] Having a girdle 
or cingulum (biol.). 

cingulum (smg'gulum) n. [L. tin* 
gulum, a girdle.] Any structure 
which is like a girdle ; a ridge 
round the base of the crown of a 
tooth ; a tract of fibres connecting 
the callosal and hippocampal con- 
volutions of the brain ; the outer 
ciliary zone on the disc of rotifers 
(anat., zool.). 




circinate (seVsmat) a. [Gk. kirkinos, 
a circle.] Rolled on the axis, so 
that the apex is the centre (bot.). 
circulation (seVkula'shun) n. [L. 
circulatio^ act of circulating.] The 
regular movement of any fluid 
within definite channels in the 
body (anat., phys.) ; the streaming 
movement of the protoplasm of 
plant cells (bot.). 

circulus (ser'kulus) n. [L. circulus, a 
circle.] Any ringlike arrangement 
of blood-vessels caused by branch- 
ing or connection with one another, 
as circulus major of iris (anat.). 
circumduction (ser'kumduk'shun) n. 
[L. circum, around ; ductus, led.] 
The form of motion exhibited by 
a bone describing a conical space 
with the articular cavity as apex 
(artaf., phys). 

circumferential (ser'kiimf eren'shal) a. 
[L. circum, around ; ferre, to bear.] 
Appl. cartilages which surround 
certain articulatory fossae (anat.). 
circumflex (seYkumfleks) a. [L. 
circum, around ; flectere, to bend.] 
Bending round ; appl. certain 
arteries, veins, nerves (anat.). 
circumfluence (serkum'flooens) n. 
[L. circum, around ; fluens, flowing.] 
In Protozoa, the engulfing of food 
by the protoplasm flowing round 
and enveloping it after contact 

circumnutation (ser'kumnuta'shun) n. 
[L. circum, around ; nutare, to 
swim.] The irregular elliptical or 
spiral movement exhibited by the 
apex of a growing stem or shoot 

circumoesophageal (ser'kumesof- 
aje'al) a. [L. circum, around ; Gk. 
oisophagos, the gullet.] Appl. 
structures or organs surrounding 
or passing along the gullet (zool.). 
circumpolar (ser'kumpo'lar) a. [L. 
circum, around ; polus, end of axle.] 
Appl. animals found at the Poles 

circumscissile (stir'kumsis'il) a. [L. 
circum, around ; scindere, to cut.] 
Appl. the form of dehiscence 
exhibited by a pyxidium (bot.). 
circumvallation (ser'kumvala'shun) n. 
[L. circum, around ; vallare, to 
wall.] In Protozoa, the ingestion of 

food by the sending out of pseudo- 
podia which ultimately surround 
without touching it (zool.). 
cirrate (sT/at) a. [L. cirratus, having 

ringlets.] Having cirri (zool.). 
cirrhus and cirrhi, see cirrus, 
cirrose (sires', sir'os) a. [L. cirrus, a 
lock.] With cirri (zool.) ; with 
tendrils (bot.). 

cirrus (sir'us) ., cirri (str'l) pltt. 
[L. cirrus, a lock.] Tendrils (bot.) ; 
the appendages of barnacles ; the 
jointed filaments of the axis or of 
the aboral surface of crinoids ; the 
barbels of fishes ; the respiratory 
and tactile appendages of worms ; 
the organs of copulation in some 
molluscs and trematodes ; hairlike 
structures on the appendages of 
insects (zool.). 

cladanthous (kladan'thCis) a. [Gk. 
klados, a sprout ; anthos, a flower.] 
Having terminal archegonia on 
short lateral branches (bot.). 

cladautoicous (klad'otoik'us) a. [Gk. 
klados, a sprout ; autos, self ; oikos, 
house.] With antheridia on a 
special stalk (hot.). 

cladocarpous (klad'tikar'pus) a. [Gk. 
klados, a sprout ; karpos, a fruit.] 
Cladanthous, which see. 

cladode (klad'od) n. [Gk. klados, a 
sprout.] A branch arising from the 
axil of a true leaf, resembling a 
foliage leaf, and consisting of a 
single internode (bot.). 

cladogenous (kladqj'enus) a. [Gk. 
klados, a sprout ; genes, birth.] 
Cladanthous, which see. 

cladome (kladom') n. [Gk. klados, a 
sprout.] The group of superficially 
situated rays in a triaene (zool.). 

cladophyll (klad'ofil) n. [Gk. klados, 
a sprout ; phyllon, a leaf.] Cladode, 
which see. 

cladoptosis (klad'opto'sis) . [Gk. 
klados, a sprout ; ptosis, falling.] 
The annual shedding of twigs 
instead of leaves (bot.). 

cladose (klad'os, klados') a. [Gk. 
klados, a sprout.] Branched (biol.). 

cladotyle (klad'otil) n. [Gk. klados, 
a sprout ; tylos, a knob.] A rhabdus 
with one actine branched, the other 
tylote (zool.). 

clasmatocyte (klazmat'oslt, klas'mato- 
sit) n. [Gk. klasHia, a fragment ; 




kytos, hollow.] A soft, much vacuo- 
lated, very variable cell in areolar 
tissue (phys.). 

claspers (klas'perz) n. plu. [M.E. 
claspen, to hold.] Rod-like pro- 
cesses on the pelvic fins of certain 
male elasmobranchs ; any modifica- 
tion of an organ or part to enable 
the two sexes to clasp one another 
(zoo/.) ; tendrils or climbing off- 
shoots (bot.). 

clathrate (klath'rat) a. [Gk. kleihra, 
a lattice.] Lattice-like (biol.). 

claustrum (klos'triim) n. [L. claus- 
trum, a bar.] In the cerebral 
hemispheres, a thin layer of grey 
substance lateral to the external 
capsule, bounding the lentiform 
nucleus^ (anat.). 

clava (kla'va) n. [L. clava, a club.] 
The knob-like end of the antennae 
of certain insects (zool.) ; the elon- 
gated swelling at the end of the 
fasciculus gracilis (anat.). 

clavate (klav'at) a. [L. clava, a club.] 
Club-shaped ; thickened at one end 

clavicle (klav'lkl) n. [L. clavis, a key.] 
The bone forming the anterior 
portion of the shoulder girdle 
(anat.) ; in animals, ventral. 

claviculariuin (klavik'ula'rium) n. [L. 
clavis, a key.] The epiplastron of 
Chelonia, probably corresponding 
to the clavicles of other forms (zool.}. 

clavula (klav'ula) n. [L. clava, a 
club.] A monactinal modification 
of a triaxon spicule ; one of the 
minute ciliated spines on the 
fascicles of Spatangidae (zool.) ; the 
clavate sporophore of certain Fungi 

clavus (kla'vus) n. [L. clavus, a nail.] 
The part of an elytron lying next 
to the scutellum in Hemiptera 

claw (klo) n. [A.S. clawu, a claw.] 
The stalk of a petal (bot.) ; a sharp 
curved nail on a finger or toe ; the 
forceps of certain crustaceans ; a 
curved process on the limbs of 
insects (zool.). 

clearing foot, the filamentous pro- 
cess of the exopodite of the second 
maxilla in the Phyllocarida (zool.). 

cleavage (kle'vaj) n. [A.S. cleofan, 
to cut.] The series of karyo- 

kinetic divisions which change the 
egg into a multicellular embryo 

cleavage nucleus, the nucleus of the 
fertilized egg, produced by the 
orderly and intimate union of the 
male and female pronuclei (cyt.). 

cleistocarp (kli'stokarp) n. [Gk. kleis- 
tos, closed ; karpos, a fruit.] Cleisto- 
thecium, which see. 

cleistocarpous (kli'stokar'pus) a. [Gk. 
kleistos, closed ; karpos, a fruit.] 
AppL mosses with non-operculate 
capsules (bot.). 

cleistogamous (kllstog'amus) a. [Gk. 
kleistos, closed ; gamos, marriage.] 
Pert, or possessed of characteristics 
of cleistogamy (bot.). 

cleistogamy (kli'stog'aml) n. [Gk. 
kleistos, closed ; gamos, marriage.] 
State of having small inconspicuous 
flowers which are self-fertilizing and 
do not open ; fertilization without 
opening (bot.). 

cleistogene (kffstojen) n. [Gk. kleis- 
tos, closed ; genos, birth.] A plant 
with cleistogamous flowers (bot.). 

cleistothecium (kll'stdthe'shmm) n. 
[Gk. kleistos, closed ; theke, a box.] 
An ascocarp which remains closed 
and produces its spores internally 

cleithrum (klr'thrum) n. [Gk. klei- 
thron, a key.] The pair of additional 
clavicles in Stegocephalia (pal.) ; 
the clavicular element of the pectoral 
girdle in some fishes (zool.). 

clinandrium (klinan'drium) n. [Gk. 
kline, bed ; aner, a man.] A cavity 
in the "column" between the 
anthers in Orchids (bot.). 

clinidium (klinid'ium) n. [Gk. kline, 
a bed.] A filament in a pycnidium 
which produces spores (bot.). 

clinosporangium (kli'nosporan'jlum) 
n. [Gk. kline, bed ; sporos, seed ; 
anggeion, a vessel.] Pycnidium, 
which see. 

clitellum (kliteTum) n. [L. clitellae, 
a pack-saddle.] The saddle or 
swollen glandular portion of the 
skin of certain worms (zool.). 

clitoris (klit'oris) n. [Gk. kleiein, to 
enclose.] An erectile organ, homo- 
logous with the penis, at the upper 
part of the vulva (anat.). 

clivus (kll'vus) n. [L. clivus, a hill.] 




A shallow depression in the sphen- 
oid, behind the dorsum sellae 

cloaca (kloa'ka, klo'aka) n. [L. cloaca, 
a sewer.] The common chamber 
into which intestinal, genital, and 
urinary canals open, in vertebrates 
except most mammals (zool.}. 

clone (klon) n. [Gk. klon, a twig.] 
Desma, which see. 

clonus (klo'nus) n. [Gk. klonos, violent 
motion.] A series of muscular con- 
tractions when the individual con- 
tractions are discernible ; incom- 
plete tetanus (phys.). 

clump (klump) v. [Ger. klump, a 
mass.] To form lumps or knots 

clypeal (klip'eal) a. [L. clypeus, a 
shield.] Pert, the clypeus of insects 

clypeate (klip'eat) a. [L. clypeus, a 
shield.]. Round or buckler-like 
(biol.) ; having a clypeus (zool.). 

clypeola (klipe'dla), clypeole (klip'eol) 
n. [L. clypeus, a shield.] A sporo- 
phyll in the spike of an Equisetum 

clypeus (klip'eus) n. [L. clypeus, a 
shield.] A shield on the antero- 
median part of an insect's head 
(zool.) ; a band of tissue round the 
mouth of a perithecium of certain 
Fungi (bot.). 

cnemldlum (nemid'ium, knemid'ium) 
n. [Gk. knemis, a legging.] The 
lower part of a bird's leg devoid of 

cnemls (ne'mis, kne'mis) n. [Gk. 
knemis, a legging.] The shin or 
tibia (zool., anat.). 

cnida (n^da, knl'da) n. [Gk. knide, a 
nettle.] A cnidoblast. 

cnldoblast (nl'doblast, knl'doblast) n. 
[Gk. knide, a nettle ; blastos, a 
bud.] A stinging cell ; a goblet- 
shaped cell with a long barbed 
thread and poisonous fluid in the 
interior, and a trigger-like process 
projecting externally, found in cer- 
tain Coelenterates (zool.). 

cnidocil (nfdtisll, knl'dosil) n. [Gk. 
knide, a nettle ; L. cilium, an eye- 
lid.] A minute process projecting 
externally from a cnidoblast (zool.). 

cnidophore (nl'dofor, knfdofor) n. 
[Gk. knide, a nettle ; pherein, to 

bear.] A modified zooid which 
bears nematocysts, of the nature 
of a dactylozooid (zool.). 

cnidopod (ni'dopod, knfdopod) n. 
[Gk. knide, a nettle ; pous, a foot.] 
The drawn-out basal part of a 
nematocyst, embedded in the meso- 
gloea (zool.). 

cnidosac (nl'dosak, knfdosak) . [Gk. 
knide, a nettle ; L. saccus, a bag.] 
A kidney-shaped swelling or battery, 
often protected by a hood, found on 
the dactylozooids of Siphonophores 

coadaptation (ko'adapta'shun) n. [L. 
cum, with ; ad, to ; aptare, to fit.] 
The correlated variation in two 
mutually dependent organs (phys.). 

coagulation (koagula'shun) n. [L. 
cum, with ; agere, to drive.] Curd- 
ling or clotting ; the changing from 
a liquid to a viscous or solid state 
by chemical reaction (phys.). 

coagulin (koag'ulin) n. [L. cogere, to 
drive together.] Any substance 
capable of coagulating albuminous 
substances (phys.). 

coagulum (koag'ulum) n. [L. cogere, 
to drive together.] Any coagulated 
mass (phys.). 

coarctate (koark'tat) a. [L. coarctare, 
to press together.] Closely con- 
nected (biol.) ; having abdomen 
separated from thorax by a con- 
striction (zool.). 

coarctate larva or pupa, semipupa ; 
pseudopupa ; a larval stage of 
certain Diptera (zool.). 

cocci (kok'sl) n. plu. [Gk. kokkos, a 
seed.] Septicidal carpels ; spore 
mother cells of certain hepatics 
(hot.) ; rounded cells, as some 
bacteria (bact.). 

coccogone (kok'ogon) n. [Gk. kokkos, 
a seed ; gonos, birth.] A repro- 
ductive cell in certain Algae (hot.). 

coccoid (kSk'oid) a. [Gk. kokkos, a 
seed ; eidos, form.] Pert, a coccus ; 
spherical or globose (bot., bact.). 

coccolith (kok'ollth) n. [Gk. kokkos, a 
seed ; lithos, a stone.] A calcareous 
spicule in certain of the Flagellates 

coccospheres (kok'osferz) n.plu. [Gk. 
kokkos, a seed ; sphaira, a globe.] 
Collections of undigested shells in 
certain Radiolarians (zool.). 




coccus (kok'us) n. [Gk. kokkos, a 
seed.] Sing, of cocci, which see. 

coccygeal (k6ksfj'eal) a. [Gk. kokkyx, 
the cuckoo.] Pert, or in the region 
of the coccyx (anat., zoo/.). 

coccyx (kok'siks) n. [Gk. kokkyx, the 
cuckoo.] The part of the vertebral 
column beyond the sacrum. 

cochlea (kok'lea) n. [Gk. kochlias, 
a snail.] A division of the ear 
spirally coiled like a snail's shell 

cochlear (kSk'lear) a. [Gk. kochlias, 
a snail] Pert, the cochlea (anat.). 

cochlearifonn (kok'lear'iform) a. [Gk. 
kochlias, a snail ; L. forma, shape.] 
Spoon-shaped (zoo/.) ; pert, the thin 
plate of bone separating the tensor 
tympani canal from the Eustachian 
tube (anat.). 

cochleate (kok'leat) a. [Gk. kochlias, 
a snail.] Screw-like (anat.). 

cocoon (kokoon') n. [F. cocon, a 
shell.] The protective case of 
many larval forms before they be- 
come pupae ; the covering formed 
by many animals for their eggs 

coelenterate (selgn'tgrat) a. [Gk. 
koilos, hollow ; enteron, intestine.] 
Pert. Coelenterata (zoo/.). 

coelenteron (se!6n't6r6n) n. [Gk. 
koilos, hollow ; enteron, intestine.] 
The cavity in the body of a Coelen- 
terate (zoo/.). 

coeliac (se'Mk) a. [Gk. koilia, belly.] 
Pert, the abdominal cavity ; appl. 
arteries, veins, nerves (anat.). 

coeloblast (se'loblast) n. [Gk. koilos, 
hollow ; blastos, a bud.] A divi- 
sion of the embryonic endoblast 

coelogastrula (se'l6gas'troola). [Gk. 
koilos, hollow ; gaster, stomach.] A 
gastrula developed from a blastula 
with a segmentation cavity (zoo/.). 

coelom (se'lom) n. [Gk. koilos, 
hollow.] A cavity of the body 
derived from the mesoblast (emo.). 

coelomate (se'lomat, selo'mat), see 

coeloinic (selom'ik) a. [Gk. koilos, 
hollow.] Pert, or having a coelom 

coelomoduct (selo'modukt) n. [Gk. 
koilos, hollow ; L. ducere, to lead.] 
The duct leading directly from the 

genital cavity to the exterior in 
Cephalopods and in Annulates 

coelomopores (selo'moporz) n. plu. 
[Gk. koilos, hollow ; poros, a 
passage.] Ducts leading directly 
from the pericardial cavity of 
Nautilus to the exterior (zoo/.). 

coelomostome (selo'mostom) n. [Gk. 
koilos, hollow ; stoma, mouth.] The 
external opening of a coelomoduct 


coelosperm (se'lospgrm) n. [Gk. 
koilos, hollow ; sperma, seed.] A 
carpel, hollow on its inner surface 

coelozoic (se'lozolk) a. [Gk. koilos, 
hollow ; zoon, an animal.] Appl. a 
trophozoite of a sporozoan when 
situated in some cavity of the body 

coenanthium (senan'thium) n. [Gk. 
koinos, common ; anthos, flower.] 
An inflorescence with a nearly flat 
receptacle having slightly upcurved 
margins (bot.). 

coenenchyma (sengng'kima), coenen- 
chyme (sengng'klm) n. [Gk. koinos, 
common ; engchyma, infusion.] The 
common tissue which connects the 
polyps or zooids of a compound 
coral (zoo/.). 

coenobium (senolaium) n. [Gk. 
fcoinos, common ; bios, life.] A 
unicellular colony with no marked 
distinction between vegetative and 
reproductive units (biol.). 

coenoblast (se'noblast) n. [Gk. koinos, 
common ; blastos, a bud.] A germ 
layer which gives origin to the 
endoderm and mesoderm (zoo/.). 

coenocyte (se'nosit) n. [Gk. koinos, 
common ; kytos, a hollow.] A plant 
body in which the constituent proto- 
plasts are not separated by cell 
walls (bot.\ 

coenoeclum (sene'shium) n. [Gk. 
koinos, common ; oikos, a house.] 
The common groundwork of a 
polyzoan colony (zoo/.). 

coenogamete (se'nogamet) n. [Gk. 
koinos, common ; gamos, union.] 
A gamete with more than one 
nucleus (bot.}. 

coenosarc (se'nosark) n. [Gk. 
koinos, common ; sane, flesh.] 
The common tissue which unites 




the various polyps in a compound 
colony (zool.}. 

coenosteum (senos'teum) n. [Gk. 
koinos, common ; osteon, a bone.] 
The common colonial skeleton in 
corals (zool.). 

coenurus (senu'riis) n. [Gk. koinos, 
common ; aura, a tail/] A meta- 
cestode with large bladder, from 
the walls of which a very large 
number of heads are formed 

coherent (kohe'rSnt) a. [L. cohaerere, 
to stick together.] With similar 
parts united (bot.). 

cohesion (kohe'zhun) n. [L. cohaerere, 
to stick together.] The condition 
of union of the separate parts of a 
floral whorl (bot.}. 

cohort (ko'hort) n. [L. cohort, an 
enclosure.] Used in earlier clas- 
sifications to denote a somewhat 
indefinitely limited group (bwl.). 

coleopterous (kol'eop'tgrus) a. [Gk. 
koleos, a sheath ; pteron, a wing.] 
Having the anterior wings hard 
and used as elytra (zool.). 

coleorhiza (kol'eori'za) n. [Gk. koleos, 
a sheath ; rhiza, a root.] The layer 
surrounding the radicle (bot.). 

colic (kol'ik) a. [Gk. kolon, the colon.] 
Pert, the colon (anat.). 

collagen (k61^j6n) . [Gk. kolla, 
glue ; genos, offspring.] A protein 
substance, probably an anhydride 
of gelatin, occurring as the chief 
constituent of the white fibres of 
connective tissue and the organic 
part of the bones (phys.). 

collar (kol'ar) n. [M.E. coler, a 
collar.] The choana of a collared 
cell ; a prominent fold behind the 
proboscis in the Hemichorda ; the 
fleshy rim projecting beyond the 
edge of a snail shell ; any structure 
likened to a collar (zool.}. 

collateral (kolat'eral) a. [L. cum, 
with ; latera, sides.] Side by 
side ; appl. bundles, as collateral 
bundle, with xylem and phloem in 
contact on one side only (dot.} ; 
appl. fine lateral branches from the 
axon of a nerve cell (anat.). 

collateral circulation, circulation 
established through anastomosis 
with other parts when the chief 
vein is obstructed (phys}. 

collenchyma (koleng'kima), collen- 
chyme (kolgng'klm) n. [Gk. kolla, 
glue ; engchyma, infusion.] Paren- 
chymatous tissue, with cells elon- 
gated and thickened at the angles 
(bot.) ; the middle layer of sponges 

collencyte (kol'enslt) n. [Gk. kolla, 
glue ; kytos, hollow.] A clear cell 
with thread-like pseudopodia found 
in sponges (zool.}. 

colleterium (ksrete'rfum) n. [Gk. 
kolla, glue.] A mucus-secreting 
gland in the female reproductive 
system of insects (zool.}. 
colleters (kole'terz) n. plu. [Gk. 
kolla, glue.] The hairs, usually 
secreting a gluey substance, which 
cover many resting buds (bot.}. 
colletocystophore (kole'tosist'ofor) n. 
[Gk. kolla, glue ; kystis, a bladder ; 
pherein, to bear.] The statorhab of 
Haliclystus (zool.). 

colliculus (kollk'ulus) n. [L. colli- 
culus, a little hill.] One of the 
prominences of the corpora quadri- 
gemina ; a rounded elevation near 
the apex of the antero-lateral surface 
of the arytaenoid cartilage (anat.). 
colloblast (kol'dblast) n. [Gk. kolla,. 
glue ; blastos, a bud.] A cell on 
the tentacles and pinnae of Cteno- 
phores, which carries little globules 
of adhesive substance (zool}. 
colloid (kol'oid) n. [Gk. kolla, glue ; 
eidos, form.] A gelatinous sub- 
stance which does not readily 
diffuse through an animal or veget- 
able membrane ; opp. crystalloid. 
collophore (kol'ofor) n. [Gk. kolla, 
glue ; pherein, to bear.] The 
ventral tube of the Collembola 

collum (kfil'um) n. [L. collum, the 
neck.] Any collar-like structure 
(biol.) ; the basal portion of the 
sporogonium in mosses (bot.). 
colon (ko'lon) n. [Gk. kolon, the 
colon.] The second portion of the 
intestine of insects ; the part of the 
large intestine stretching from its 
junction with the small intestine to 
the rectum (zool., anat.). 
colony (kol'onl) n. [L. colonia, a 
farm.] Any collection of organisms 
living together, appl. ants, bees ; 
a group of animals or plants living 




together and somewhat isolated ; 
a group of bacteria in a culture 
(dial.) ; term appl. all the " persons " 
in a colonial Coelenterate (zool.). 

columella (kgl'iimeTa) n. [L. columen, 
a column.] A prolongation of the 
stalk into the sporangium (bot.) ; 
the central pillar in the skeleton of 
some corals ; the rod, partly bony, 
partly cartilaginous, connecting the 
tympanum with the inner ear in 
birds, reptiles, and amphibians ; the 
central pillar in gasteropod shells 
(zool.) ; the axis of the cochlea 

columellar (kol'umeTar) a. [L. colu- 
men, a column.] Pert, a colu- 

column (kol'um), columna (kolum'na) 
n. [L. columen, a column.] Any 
structure likened to a column, as 
spinal column ; the actinian body ; 
the stalk of a crinoid ; a longitudinal 
bundle of nerve fibres in the white 
matter of the spinal cord (zool.) ; 
the nasal septum edge ; thick 
muscular strands found in the 
ventricle of the heart (anat.) ; the 
stamens in the mallows ; the united 
stamens and pistil in the orchids 

columnals (kolum'nalz) n. plu. [L. 
columen, a column.] Stem ossicles 
in crinoids (zool.). 

columnar (kSlum'nar) a. [L. columen, 
a column.] Pert, a column or 

coma (ko'ma) n. [Gk. kome, hair.] 
A terminal cluster of bracts as in 
the pine-apple ; hairs found on 
certain seeds (bot.) ; stupor (pkys.). 

comb-ribs, combs, see swimming- 

comes (ko'mez) n. [L. comes, a com- 
panion.] A blood-vessel that runs 
alongside a nerve (anat.}. 

comitalia (kom'Ital'Ia) n. plu. [L. 
comitari, to accompany.] Small 
di- or tri-actine spicules which 
accompany the principal spicules 
in sponges (zool.). 

commensal (komfin'sal) n. [L. cunt, 
with ; mensa, a table.] An organism 
living with another and sharing 
the food, both species as a rule 
benefiting by the association. 

comminator (kom'Inator) a. [L. cum, 

with ; minarf, to threaten.] 
muscles which connect adjacent 
jaws in Aristotle's lantern (zool.). 

commissure (kSm'lsur) n. [L. cum, 
together ; mittere, to send.] The 
union-line between two parts ; a 
connecting band of nerve tissue 
(zool., anat.) the carpellary co- 
hesion plane (dot.). 

communistic (kom'unis'tik) a. [ 
munis, common.] Appl. animals 
which live or have their nests 

comose (ko'mos) a. [L. comosus, 
hairy.] Furnished with a tuft of 
hairs (bot.). 

compass (kom'pas) n. [L. cum, to- 
gether ; passus, a pace.] A curved 
bifid structure, part of Aristotle's 
lantern (zool.). 

complemental male, a purely male 
form, usually small, found living in 
close proximity to the ordinary 
hermaphrodite form in certain 
animals, as barnacles. 

complexus (kompleVsus) n. [L. cum, 
together ; plectere, to knit.] An 
aggregate ; appl. muscles (anat.). 

complicant (kSm'plikant) a. [L. cum, 
together ;pltcare, to fold.] Folding 
over one another ; appl. the elytra 
of certain insects (zool.). 

complicate (kfim'pllkat) a. [L. cum, 
together ; plicare, to fold.] Folded ; 
appl. insect wings (zool.) ; appl. 
leaves folded longitudinally so that 
the right and left halves are in 
contact (bot.). 

composite (kom'poslt) a. [L. cum, 
together ; ponere, to place.] Having 
the characteristics peculiar to the 
Compositae (oof.). 

compound (kom'pownd) a. [L. cum, 
together ; ponere, to place.] Made 
up of several elements; appl. flowers, 
leaves, eyes. 

compressor (komprgs'or) n. [L. cum, 
together ; premere, to press.] Some- 
thing that serves to compress ; appl. 
muscles (anat.). 

conarium (kona'rmm) n. [Gk. kona- 
rion, a little cone.] Transparent 
deep-sea larva of Vellella with red 
endoderm (zool.). 

concentric (konsgn'trik) a. [L. cum, 
together ; centrum, a centre.] 
Having a common centre (biol.) ; 




appl. bundles with wood in centre 
surrounded by bast (bot.}. 

conceptacle (konsSp'takl) n. [L. con- 
cipere, to conceive.] A depression 
in the thallus of certain Algae in 
which the reproductive organs are 
borne (dot.}. 

concha (kong'ka) n. [Gk. kongche, 
shell.] The cavity which opens 
into the meatus (anat.} ; the external 
ear ; a projection from the lateral 
wall of the olfactory organ (zool.}. 

conchiform (kSng'klform) a. [Gk. 
kongche, a shell ; L. forma, shape.] 
shaped like a concha ; shell- 
shaped (biol.}. 

conchiolin (kfingkl'dlin) n. [Gk. 
kongche, a shell.] The organic 
substance that forms the basis of 
the shells of molluscs. 

conchology (kongk61'6jl) n. [Gk. 
kongche, a shell ; logos, discourse.] 
The branch of zoology dealing with 
molluscs or their shells. 

conchula (kong'kula) n. [Gk. kongche, 
a shell.] The conspicuous pro- 
tuberant lip of the modified sulcus 
in Peachia (zool.}. 

concolorate (konkul'orat) a. [L. cum, 
with ; color, colour.] Similarly 
coloured on both sides ; appl. wings 
of insects. 

concrescence (konkreVgns) n. [L. 
cum, together ; crescere, to grow.] 
The growing together of parts (biol.}. 

conducting (kSnduk'tlng) a. [L. 
conducere, to lead together.] Con- 
veying ; appl. tissues, bundles (bot.}. 

conduction (kfinduk'shun) n. [L. 
conducere, to lead together.] The 
transference of soluble matter from 
one part of a plant to another (bot.}. 

conductivity (kSn'duktlv'ttl) n. [L. 
conducere, to lead together.] Power 
of transmitting stimuli from a part 
irritated to others more or less 
remote (phys.}. 

conduplicate (kondu'plikat) a. [L. 
conduplicare, to fold together.] 
Complicate, which see. 

condylar (k6n'd!lar) a. [Gk. kondylos, 
a knuckle.] Pert, a condyle (anat.}. 

condyle (kon'dil) n. [Gk. kondylos, 
a knuckle.] A process on a bone 
for purposes of articulation. 

condyloid (kon'diloid) a. [Gk. kon- 
dylos, a knuckle ; eidos, form.] 

Shaped like, or situated near a 
condyle (anat., zool}. 

cone (kon) n. [Gk. konos, a cone.] 
The female flower of the Coniferae, 
with woody axis and spirally- 
arranged carpels (dot.} a conical 
elevation on an egg just before 
fertilization (emb.} ; a conical or 
flask-shaped cell of the retina 

cone of origin, the small clear area 
at the point of exit of the axon 

cone-bipolars, bipolar cells whose 
inner ends ramify in contact with 
the dendrites of the ganglionic 
cells (anat.}. 

confluence (kon'flooSns) n. [L. cum, 
with ; fluere, to flow.] The angle 
of union of the superior sagittal 
and transverse sinuses of the 
occipital bone (anat.}. 

congeneric (kon'jeneYflc) a. [L. 
congener, of the same race.] 
Belonging to the same genus 

congenital (konjen'ital) a. [L. cum, 
with ; gignere, to beget.] Present 
at birth (anat.}. 

conglobate (konglo'bat) a. [L. cum, 
together; globus, a ballj Ball- 
shaped ; appl. the gland on the 
lower side of the ductus ejacu- 
latorius in insects (zool.}. 

conglomerate (k5ngl5m'Srat) a. [L. 
cum, together ; glomerare, to wind.] 
Bunched or crowded together (dot.}. 

conical (kon'ikai) a. [Gk. konos, a 
cone.] Cone-shaped ; appl. calyx, 
ventricle, etc. (biol.}. 

conidial (konid'ial) a. [Gk. konis, 
dust.] Pert, a conidium. 

conidiiferous (kfinld'nfe'rus) a. [Gk. 
konis, dust ; L. ferre, to bear.] 
Giving rise to conidia (bot.}. 

conidiophore (konid'iofor) n. [Gk. 
konis, dust ; pherein, to bear.J A 
branch of the hyphae which bears 
the conidia (bot.}. 

conidium (kontd'ium) n. [Gk. konis, 
dust] A fungal spore asexually 
produced and carried usually on 
sterigmata (bot.}. 

coniferous (kontf'e'rus) a. [Gk. konos, 
a cone ; L. ferre, to bear.] Cone- 
bearing (bot.}. 

conjugation (kSn'jooga'shun) n. [L. 




cum, together with ; jugare, to 
yoke.] The temporary union or 
complete fusion of two gametes 
or unicellular protists, which 
involves the fusion of their nuclei 
or at least a nuclear exchange 

conjunctiva (konjungktl'va) n. [L. 
cum, together ; jungere, to join.] 
The mucous membrane of the eye, 
lining the eyelids and reflected 
over the fore part of the sclera and 
cornea (anat.). 

connate (kon'nat, konat') a. [L. cum, 
together ; natus, born.] Firmly 
joined together from birth (Hoi.). 

connate-perfoliate, joined together 
at the base so as to surround the 
stem (tot.). 

connective (kongk'tiv) n. [L. cum, 
together ; nectere, to bind.] A 
connecting band of nerve tissue 
between two ganglia (zool.) ; the 
tissue separating the two lobes of 
an anther (dot.). 

connective tissue, a mesoblastic 
tissue with a large amount of 
intercellular substance in which 
fibres are developed (anat.). 

connivent (konl'vgnt) a. [F. conniver, 
to wink.] Converging (Hoi.). 

conoid (ko'noid) a. [Gk. konos, a 
cone ; eidos, form.] Cone-like, 
but not quite conical (dial.). 

conoid ligament, one of the fasciculi 
of the coraco-clavicular ligament 

conoid tubercle, a small rough 
eminence on the posterior border 
of the clavicle, serving for the 
attachment of the conoid ligament 

consensual (konsSn'sual) a. [L. 
consentire, to feel together.] Appl. 
involuntary action correlated with 
voluntary action (phys.). 

constant (kon'stant) a. [L. constans, 
unchanged.] Changeless ; invari- 
able ; appl. characters, structures 

constricted (konstrik'tgd) a. [L. 
constrictus, drawn together.] Com- 
pressed at regular intervals (tot.). 

constrictor (konstrik'tfir) n. [L. con- 
strictus, drawn together.] A muscle 
which compresses or constricts, e.g., 
constrictor urethrae (anat.). 

contabescence (kfin'tabe's'e'ns) n. [L. 
contabescere, to waste away.] Stamen 
abortion (hot.). 

context (kon'te'kst) n. [L. cum, 
together ; texere, to weave.] The 
layers developed between the 
hymenium and the true mycelium 
in certain Fungi (tot.). 

continuity (kSn'tfnu'iti) n. [L. con- 
tinuus, continuous.] Succession 
without a break, as continuity of 
the germ plasm (zool.). 

continuous (kontln'uiis) a. [L. con- 
tinuus, uninterrupted.] Not seg- 
mented or articulated (Hoi.). 

contorted (kontor'tgd) a. [L. con- 
torquere, to twist together.] Twisted ; 
appl. aestivation in which one leaf 
overlaps the next with one margin, 
and is overlapped by the previous 
on the other (tot.). 

coiitortuplicate (kon'tortu'pllkat) a. 
[L. cum, with ; torquere, to twist ; 
plicare, to fold.] A bud with con- 
torted and plicate leaves (tot.). 

contour (kon'toor) n. [F. contoumer, 
to twist.] Outline of a figure or 
body ; appl. the outermost feathers 
that cover the body of a bird, the 
contour feathers (zool.). 

contractile (kontrak'til) a. [L. cum, 
together ; trahere, to draw.] Cap- 
able of contracting (Hoi.). 

contractile cell, any cell in a spor- 
angium or an anther wall which by 
hygroscopic contraction helps to 
open them (bot.). 

contractile fibre -cells, elongated, 
spindle-shaped, more or less poly- 
hedral, nucleated muscle-cells, con- 
taining a central bundle of fibrillae 

contractile vacuole, a small spherical 
vesicle, found in the cytoplasm of 
many Protista, which appears and 
disappears with regularity (Hoi.). 

contractility (kon'traktil'iti) n. [L. 
cum, together ; trahere, to draw.] 
The power by which muscle-fibres 
are enabled to contract (phys.). 

contracture (kontrak'tur) n. [L. con- 
tractus, drawn together.] Contrac- 
tion of muscles persisting after the 
stimulus has been removed, seen 
especially in strong direct stimula- 
tion, and as death approaches 



conuli (kon'ull) n. plu. [Gk. konos, a 
cone.] The tent-like projections on 
the surface of certain Sponges caused 
by the principal skeletal elements 

conus (ko'nus) n. [Gk. konos, a cone.] 
Any cone-shaped structure, as the 
conus arteriosus, a structure between 
the ventricle and aorta in fishes and 
amphibians (zool.) ; thediverticulum 
of the right ventricle from which the 
pulmonary artery arises ; conus 
medullaris, the tapering end of the 
spinal cord (anat.). 

convergence (k6nv6r'j6ns) n. [L. 
convergere, to incline together.] 
The development of similar char- 
acters in organisms belonging to 
different groups (biol.). 

convolute (kon'volut) a. [L. cum, 
together ; volvere, to wind.] Rolled 
together ; appl. leaves and coty- 
ledons (hot.) ; appl. shells in which 
the outer whorls overlap and con- 
ceal the inner (zool.). 

convolution (kon'volu'shun) n. [L. 
cum, together ; volvere, to wind.] 
A coiling or twisting, as of the 
brain, the intestine (anat). 

coprodaeum (kop'rode'um) n. [Gk. 
kopros, dung ; odos, a way.] The 
division of the cloaca which receives 
the rectum (zool.). 

coprolite (kop'rollt) n. [Gk. kopros, 
dung ; lithos, a stone.] Petrified 

coprophagous (koprof'agus) a. [Gk. 
kopros, dung ; phagein, to eat.] 
Feeding on dung ; appl. insects. 

copula (kSp'ula) n. [L. copula, a 
bond.] A ridge in the development 
of the tongue formed by the union 
of the ventral ends of the second 
and third arches (anat.). 

copularium (kop'ula'rium) n. [L. 
copula, a bond.] A cyst formed in 
gregarines round two associated 
gametocytes (zool.). 

copulation (kop'ula'shun) n. [L. 
copula, a bond.] Sexual union ; 
coition (biol.). 

coracoid (ko/akoid) a. [Gk. korax, a 
crow ; euios, form.] Pert, the bone or 
process in the pectoral girdle (zool.). 

coracoid bone, the part of the pectoral 
girdle between scapula and sternum 

coracoid ligament, the ligament 
which stretches over the supra- 
scapular notch (zool.). 

coracoid process, the rudimentary 
coracoid element in most mammals 
fused to the scapula (zool.). 

coralliferous (kor'alif'erus) a. [Gk. 
korallion, coral ; L. ferre, to bear.] 
Coral - fo rmin g ; made of coral 

coralline (kor'alin) a. [Gk. korallion, 
coral.] Resembling a coral ; appl. 
Hydroids and Polyzoa ; composed 
of coral (zool.) ; appl. certain Algae 

corallite (kor'allt) n. [Gk. korallion, 
coral.] Cup of a single polyp of 
coral (zool.). 

coralloid (kor'aloid) a. [Gk. korallion, 
coral ; eidos, form.] Resembling, 
or branching like a coral (biol.). 

corallum (koral'um) n. [Gk. korallion, 
coral.] The skeleton of a compound 
coral (zool.). 

corbicula (korbik'ula) n. [L. corbis, a 
basket] The pollen apparatus of 
a bee ; the fringe of hair on the 
tibia (zool.). 

corbula (kor'bula) n. [L. corbis, a 
basket.] The phyllactocarp of 
Aglaeophenia, etc., a stem with 
alternate branches rising upwards 
and forming a pod-like structure 

cord (k&rd) n. [Gk. chorde, a cord.] 
Any chord-like structure, as spinal, 
spermatic cord (anat.). 

cordate (k&r'dat) a. [L. cor, the 
heart.] Heart-shaped (bot.). 

cordiform (k6r'dlform) a. [L. cor, the 
heart ; forma, shape.] Heart-shaped 

cordiform tendon, the central apo- 
neurosis of the diaphragm (anat.). 

cordylus (k&r'dilus) n. [Gk. kordyle, 
a swelling.] An intertentacular 
exumbral structure with core of 
vacuolated cells and flattened ecto- 
derm (zool). 

coriaceous (ko'ria'shus) a. [L. corium, 
leather.] Leathery ; appl. leaves 

corium (ko'rium) n. [L. corium, 
leather.] The middle division of 
an elytron (zool.) ; the deeper-seated 
layer of the skin, consisting of a 
vascular connective tissue [(anat.). 




cork (kork) ;/. [Sp. alcorque, cork.] 
A tissue derived usually from the 
outer layer of the cortex in woody 
plants (dot.}. 

conn (korm), cormus (kor'mus) n. 
[Gk. kormos, a trunk.] An en- 
larged solid subterranean stem, 
rounded in shape, composed of two 
or more internodes and covered 
externally by a few thin membran- 
ous scales or cataphyllary leaves 

cormel (kor'mel) n. [Gk. kormos, a 
trunk.] A secondary corm pro- 
duced by an old corm (hot.). 

cormidium (kormld'ium) n. [Gk. 
kormos, a trunk.] An aggregation 
of individuals in a Siphonophore, 
borne on the coenosarc and capable 
of liberation therefrom (zool.}. 

cormoid (kor'moid) a. [Gk. konnos, 
a trunk ; eidos, form.] Like a corm 

connophylogeny (kor'mofiloj'e'n!) n. 
[Gk. kortnos, a trunk ; phyle, a 
tribe ; genos, offspring.] The de- 
velopment of families or races 

cormophyte (kor'moflt) n. [Gk. 
kormos, a trunk ; phyton, a plant.] 
A plant which possesses stem, root, 
and leaf (dot,). 

cormous (kor'mus) a. [Gk. korinos, 
a trunk.] Conn-producing (bot.}. 

cornea (kor'nea) n. [L. corttu, horn.] 
The transparent covering on the 
anterior surface of the eyeball 
(anat., zool.} ; the outer transparent 
part of each element of a compound 
eye (zool.}. 

corneagen (kor'neajen') a. [L. cornu, 
horn ; Gk. genos, offspring.] Cornea- 
producing ; appl. cells lying immedi- 
ately below the cuticle, which secrete 
the cuticularlens and are renewed on 
ecdysis (zoo/.). 

corneal (kor'neal) a. [L. cornu, horn.] 
Pert, the cornea. 

corneous (kor'neus) a. [L. cornu, 
horn.] Horny ; appl. the sheath 
covering the bills of birds. 

corniculate (kornik'ulat) a. [L. cornu, 
horn.] Having horns (zool.}. 

corniculate cartilages, two small, 
conical, yellow elastic cartilages 
articulating with the summit of the 
arytaenoid cartilages (anat., cool.}. 

corniculum (kornik'ulum) n. [L. 
cornu, horn.] A small horn or 
horn-like process. 

cornua (kor'nua) n. plu. [L. cornu, 
horn.] Horn-like prolongations ; 
appl. bones, nerve tissues, cavities, 

cornucopia (kor'nuko'pia) ;/. [L. 
cornu, horn ; copia, plenty.] The 
horizontal portion of the taeniae of 
the fourth ventricle (anat.}. 

cornute (kornut') a. [L. cornu, horn.] 
With horn-like processes (bot.}. 

corolla (korol'a) n. [L. corona, a 
crown.] The petals of a flower 

corollaceous (kor'ola'shus) a. [L. 
corona, a crown.] Pert, a corolla 

corolliferous (kor'ollf'erus) a. [L. 
corona, a crown ; ferre, to bear.] 
Having a corolla (bot.}. 

corona (koro'na) n. [L. corona, a 
crown.] A cup-shaped body formed 
by the union of scales on the peri- 
anth leaves at the junction of claw 
and limb (bot.} ; the theca and arms 
of a Crinoid ; the ciliated disc of 
certain animals (zool.} ; the head 
or upper portion of any structure 

corona radiata, the layer of cells 
immediately surrounding the mam- 
malian egg (emb.} ; the fibres of the 
internal capsule (anat.}. 

coronal (koronal) a. [L. corona, a 
crown.] Situated or lying in the 
coronal sutural plane (anat.}. 

coronary (ko/onari) a. [L. corona, a 
crown.] Crown-shaped or crown- 
like ; appl. arteries, bones, sinuses, 
ligaments (anat., zool.}. 

coronary arteries, arteries supply- 
ing the tissue of the heart itself 

coronary bone, a small conical bone 
in the mandible of reptiles ; the 
small pastern bone of the horse 

coronary sinus, a venous channel in 
the posterior part of the coronary 
sulcus and covered by muscular 
fibres from the left atrium (anat.}. 

coronated (kor'ona'tgd) a. [L. corona, 
a crown.] Supplied with a crown 
(zool., bot.}. 

coronet (kor'onfit) /;. [L. corona, a 




crown.] The burr of an antler 

coronoid (kor'onoid) a. [Gk. korax, 
a crow ; eidos, form.] Shaped like 
a beak ; appl. processes (anat.}. 

corpora adlposa, the fat bodies of 
amphibians, attached to the dorsal 
wall of the body cavity (zool.}. 

corpora cavernosa, erectile masses 
of tissue, stiffening the anterior 
surface of the penis (anat., zool.}. 

corpora quadrigemina, four rounded 
eminences which form the dorsal 
part of the mesencephalon (anat.}. 

corpus (kor'pus) n., corpora (kor'pora) 
plu. [L. corpus, a body.] Any 
fairly homogeneous structure which 
forms part of an organ (anat.}. 

corpus spcmgiosum, a mass of 
erectile tissue forming the posterior 
wall of the penis (anat., zool.}. 

corpuscle (kor'pusl, korpus'l) n. [L. 
corpusculus, a small body.] A 
protoplasmic cell, floating freely in 
some fluid, or embedded in some 
matrix ; appl. various sensory struc- 
tures (anat.} ; any small proto- 
plasmic mass of definite function 
or shape (bot.}. 

correlation (kSr'gla'shun) n. [L.L. 
correlatio, relationship.] Similarity 
or mutual relationship (biol.}. 

corrugator (ko/ooga'tor) a. [L. 
cum, together ; rugare, to wrinkle.] 
Wrinkled or wrinkling ; appl. 
muscles (anat.}. 

cortex (kor'teks) n. [L. cortex, bark.] 
The extrastelar fundamental tissue 
of the sporophyte (bot.} ; the outer 
or more superficial part of an organ 

cortical (kor'tikal) a. [L. cortex, 
bark.] Pert, the cortex. 

corticate (k&r'tikat) a. [L. cortex, 
bark.] Having a special outer 
covering (anat., biol.}. 

corticiferous (kor'tislf'e'rus) a. [L. 
cortex, bark ; ferre, to carry.] 
Forming or having a bark-like 
cortex (bot.}. 

corticostriate (kor'tikostrfat) a. [L. 
cortex, bark ; stria, a channel.] 
Appl. fibres which join the corpus 
striatum to the cerebral cortex 

cortina (k&rtfna) n. [L. cortina, a 
curtain.] The velum in Agarics (bot.}. 

cortlnate (k&r'tlnat) a. [L. cortina, 
a curtain.] Having a velum ; of a 
cobweb-like texture (bot.}. 

Corti's organ, the organon- spirale, 
placed on the inner portion of the 
membrana basilaris of the ear 

corymb (kor'imb) n. [Gk. korymbos, 
a cluster of flowers.] A raceme 
with lower pedicels elongated so 
that the top is nearly flat (bot.}. 

corymbose (kor'imbos) a. [Gk. 
korymbos, a cluster of flowers.] 
Pert, or like a corymb ; arranged 
in a corymb (bot.}. 

cosmine (kos'min) n. [Gk. kosmios, 
regularly.] The outer regular layer 
of dentine-like material in ganoid 
scales (zool.}. 

cosmopolite (kozmop'ollt) a. [Gk. 
kosmos, world ; polites, citizen.] 
World-wide in distribution (biol.}. 

costa (kos'ta) n. [L. costa, a rib.] A 
rib ; anything rib-like in shape 
(anat.} ; anything rib-like, as a ridge 
on shell, coral, insect-wing (zool.}. 

costal (kps'tal) a. [L. costa, a rib.] 
Pert, ribs or rib-like structures ; 
appl. the bony shields of Chelonia ; 
pert, the primary brachial series in 
crinoids (zool.} ; pert, a main rib 

costalia (kosta'lia) n. plu. [L. costa, 
a rib.] The supporting plates in 
the theca of the Cladoidea (zool.}. 

costate (kos'tat) a. [L. costa, a rib.] 
With one or more longitudinal ribs 
(bot.} ; with ridges or costae (zool.}. 

coterminous (koteYminus) a. [L. 
cum+ with ; terminus, an end.] Of 
similar distribution (biol.}. 

cotyledon (kot'ile'don) n. [Gk. kotyle, 
a cup.] The primary or first leaf of 
an embryonic sporophyte (bot.} ; the 
definite patches of villi on the 
placenta of a mammal (zool.}. 

cotyledonary (kot'lle'donari) a. [Gk. 
kotyle, a cup.] Pert, cotyledons 
(bot.} ; with cotyledons on the 
placenta (zool.}. 

cotyloid (kot'floid) a. [Gk. kotyle, a 
cup ; eidos, form.] Cup-shaped ; 
pert, the cotyloid cavity (anat.}. 

cotylophorous (kot'ilof'orus) a. [Gk. 
kotyle, a cup ; pherein, to bear.] 
With a cotyledonary placenta 




cotype (ko'tip) n. [L. cum, with ; 
typus, an image.] An additional 
type specimen, frequently collected 
in the same place at the same time, 
or a specimen from a description of 
which, along with others, the type 
is drawn up (biol.). 

cover-scales, small scales arranged 
spirally and developed directly on 
the axis of a cone of the Coniferae 

covert (kuv'ert) n. [F. couvrir, to 
cover.] Appl. the feathers cover- 
ing the bases of the quills in birds. 

cowled (kowld) a. [L. cucullus, a 
hood.] Furnished with or shaped 
like a hood. 

coxa (kok'sa) n. [L. coxa, hip.] 
The proximal joint of an insect 
leg (zool.). 

coxal (kok'sal) a. [L. coxa, hip.] 
Pert, the coxa (zool.). 

coxopodlte (koksop'odft) n. [L. coxa, 
hip ; Gk. pous, a foot.] The proxi- 
mal part of the protopodite of a 
crustacean limb (zoo/.). 

crampon (kram'pon) n. [O.H.G. 
chramph, crooked.] An aerial 
root, as in the ivy (pot.). 

cranial (kra'nlal) a. [Gk. kranion, 
the head.] Pert, the skull, or 
that part which encloses the 
brain ; appl. nerves, muscles, 
blood-vessels, bones, etc. 

craniate (kra'nlat) a. [Gk. kranion, 
the head.] Having a skull (zool.). 

craniology (kra'niol'ojT) n. [Gk. 
kranion, the head ; logos, dis- 
course.] The study of the skull 

craniometry (kra'niom'fitri) n. [Gk. 
kranion, the head ; metron, a 
measure.] The science of the 
measurement of skulls. 

cranium (kra'nium) n. [Gk. kranion, 
the head.] The skull of any craniate, 
or more particularly, that part en- 
closing the brain (anat., zool.). 

craspedodromous (kras'pedod'romus) 
a. [Gk. kraspedon, an edge ; dro- 
mein, to run.] With nerves running 
directly from mid-rib to margin 

. (bot.). 

craspedote (kras'pedot) a. [Gk. 
kraspedon, an edge.] Having a 
velum (zool.). 

craspedum (kras'pedum) ;/. [Gk. 

kraspedon, an edge.] A mesen- 
teric filament of sea-anemones 

craticular (kratfk'ular) a. [L. crati- 
cula, a gridiron.] Crate-like ; 
appl. a stage in the life-history 
of a diatom where new valves are 
formed before the old are lost 

creatine (kre'atm) n. [Gk. kreas, 
flesh.] A nitrogenous substance 
found in the muscles, brain, and 
blood of vertebrates (phys.). 

creatinine (kreat'inen) n. [Gk. kreas, 
flesh.] A nitrogenous substance 
found in muscles and urine (phys.). 

cremaster (kremas'tr) n. [Gk. 
kremannunai, to hang.] A thin 
muscle in the spermatic cord 
(anat.) ; a stout terminal abdominal 
spine in subterranean insect pupae; 
the anal hooks for pupae suspension 

cremocarp (krSm'okarp) n. [Gk. 
kremannunai, to hang ; karpos, 
fruit.] An inferior, dry, indehiscent, 
two-celled, two-seeded fruit (do/.). 

crenate (kre'nat, krgn'at) a. [L. crena, 
a notch.] With scalloped margins 

crenulated (kren'ulated) a. [Dim. 
of L. crena, a notch.] With margins 
minutely crenate (bot.). 

crepis (kre'pis) n. [L. crepis, un- 
known.] The term appl. the funda- 
mental spicule by deposition of 
silica upon which a desma is 
formed (zool.). 

crepitation (krgplta'shun) . [L. 
crepare, to crack.] In insects, the 
discharge with an explosive sound 
of a fluid (zool.). 

crepuscular (krgpus'kular) a. [L. 
crepusculum, dusk.] Flying before 
sunrise or in twilight ; appl. certain 
insects and birds (zool.). 

crescent (krSs'fint) n. [L. crescere, 
to grow.] A term appl. various 
crescentic structures found in 
glands (anat.). 

crescents of Gianuzzi (janopt'se), 
small crescent-shaped bodies with 
polyhedral granular cells lying 
between the cells and the membrana 
propria in certain alveoli of the 
salivary glands (anat.). 

crest (krgst) //. [L. cresla, a crest.] 




A ridge on a bone ; a fleshy longi- 
tudinal ridge as in newts (zool.). 

cretaceous (kreta'shus) a. [L. creta, 
chalk.] Appl. the entire period 
between the Jurassic and Tertiary, 
or the upper division of this period 

cribellum (kribel'um) n. [L. cribrum, 
a sieve.] A special spinning organ 
found only in certain spiders (zool.). 

cribriform (krib'riform)a. [L.cribruin, 
a sieve ; forma, shape.] Sieve-like 
(bot., anat., zool.). 

cribriform cell, sieve cell (bot.). 

cribriform organ, the folded mem- 
brane carrying papillae in the 
interradial angles of certain star- 
fishes (zool.). 

cribriform plate, the horizontal 
portion of the ethmoid perforated 
with many foramina for the exit of 
the olfactory nerves (anat., zool.). 

cricoid (knk'oid) n. [Gk. krikos, a 
ring ; eidos, form.] A ring-like 
cartilage in the larynx, articulating 
with the thyroid and the arytaenoid 
cartilages (anat.). 

crissal (kris'al) a. [L. crissare, to 
move the haunches.] Pert, the 
crissum (zool.). 

crissum (krib'um) ;/. [L. crissare, to 
move the haunches.] The circum- 
cloacal region of a bird, or the 
feathers thereon (zool.). 

crista (krls'ta) n. [L. crista, a crest.] 
A crest or ridge ; the projection 
from the ectoloph into the median 
valley in lophodont molars (zool.). 

crochet (kroch'gt) n. [F. crochet, a 
small hook.] The projection of 
the protoloph in lophodont molars 

crop (krop) n. [M.E. croppe, top of a 
plant] A sac-like dilatation of the 
gullet of a bird ; a similar structure 
in an insect or worm (zool.). 

cross (kros) n. [M.E. crois, a cross.] 
An organism produced by the 
mating of parents of different 
breeds (biol.). 

crotaphite (krot'aflt) n. [Gk. krot- 
aphos, of the temples.] The 
temporal fossa (anat.). 

crotchet (kroch'et) n. [F. crochet, a 
small hook.] A curved chaeta, 
notched at the end (zool.). 

crown (krown) n. [L. corona, a 

crown.] The grinding surface of 
a tooth ; the distal part of an 
antler ; the crest, the head ; the 
cup and arms of a crinoid (zool.). 

crucial ligaments, two ligaments 
which connect the femur and tibia 
in the knee-joint (anat.). 

cruciate (kroo'shlat, kroo'siat) a. [L. 
crux, cross.] With leaves or petals 
in the form of a cross (bot.) ; 
Y-shaped or + -shaped, appl. 
muscles, ligaments (anat.). 

cruor (kroo'or) n. [L. cruor, blood.] 
The clots in coagulated blood 

cruorin (kroo'orln) n. [L. cruor, 
blood.] Haemoglobin (phys.). 

crura cerebri, two cylindrical masses 
at the base of the brain, they emerge 
from the pons and disappear into 
the substance of the cerebral hemi- 
spheres (anat.). 

crural (kroo'ral) a. [L. crus, leg.] 
Pert, the thigh (anat). 

crureus (kroo'reus) n. [L. crus, leg.] 
The vastus internus muscle of the 
thigh (a?iat.). 

crus (krus) n., crura (kroo'ra) plu. 
[L. crus, leg.] The shank ; any 
body likened to a leg or to a pair 
of legs (anat.). 

crusta (krus'ta) n. [L. crusta, a 
shell.] The ventral part of the 
substantia nigra of the cerebral 
peduncles (anat.) ; the cement layer 
in teeth (zool.). 

crustaceous (krusta'shus) a. [L. 
crusta, a shell.] With crustacean 
characteristics (zool.). 

crypt (kript) n. [Gk. kryptos, hidden.] 
A simple glandular tube or cavity 

cryptocarp (krip'tokarp) n. [Gk. 
kryptos, hidden ; karoos, fruit.] A 
fruit-like structure which is really 
the sporophyte phase in the Red 
Algae (bot.). 

cryptogam (krip'togam) n. [Gk. 
kryptos, hidden ; gamos, union.] A 
name given to that group of plants 
for the supposed reason that sexual 
reproduction was concealed ; cf. 
phanerogam (bot.). 

cryptoneurous (krip'tonu'rus) a. [Gk. 
kryptos, hidden ; neuron, nerve.] 
With no definite or distinct nervous 
system (zool.). 




cryptostomata (krip'tbstom'ata) n.plu. 
[Gk. kryptos, hidden ; stoma, mouth.] 
Non-sexual conceptacles in the 
Fucaceae (hot.}, 

cryptozoic (krip'tozo'fk) a. [Gk. 
kryptos, hidden ; zoon, animal.] 
Appl. fauna dwelling in darkness, 
or under stones, bark, etc. (biol.}. 

crystallin (kris'talin) n. [Gk. krys- 
tallos, ice.] A globulin which is 
the principal chemical constituent 
of the lens of the eye (pkys.}. 

crystalline (kris'talln) a. [Gk. krys- 
talltnos, crystalline.] Transparent ; 
appl. various structures (anat.}. 

crystalloid (kris'taloid) n. [Gk. 
krystallos, ice ; eidos, form.] A 
substance which in solution readily 
diffuses through an animal mem- 
brane ; opp. colloid ; appl. crystal 
of proteid matter found in oily 
seeds (bot.}. 

ctene (ten, kten) n. [Gk. kteis, a 
comb.] The swimming-plates of 
Ctenophores (zoo/.). 

ctenidium (temd'ium, ktgntd'ium) n. 
[Gk. kteis, a comb.] The respira- 
tory apparatus in the Mollusca, 
feather-like or comb like in appear- 
ance (zool.}. 

ctenocyst (tgn'dsist, ktgn'ostst) n. 
[Gk. kteis, a comb ; kystis, a bladder.] 
The aboral sense organ of the 
Ctenophora (zool.}. 

ctenoid (tSn'oid, kte'noid) a. [Gk. 
kteis, a comb ; eidos, resemblance.] 
With a comb-like margin, appl. 
scales (zool.}. 

ctenophoral (tgnof'dral, ktenof'dral) 
a. [Gk. kteis, a comb ; pherein, 
to bear.] Supplied with swimming- 
plates (zool.}. 

cubital (kutrftil) a. [L. cubitalis, of 

] ~>rf. the 

the elbow. Pert, 

ulna (ana/., 

cubitus (ku'bitus) n. [L. cubitus, the 

elbow.] The ulna, forearm (anat.} ; 

the primary vein in an insect's wing 

cuboid (ku'boid) a. [Gk. kuboeides, 

cube-like.] Nearly cubic in shape 

(anat.} ; #., the outermost of the 

distal tarsal bones (zool.}. 
cuboidal (kuboid'al) a. [Gk. kuboeides t 

cube-like.] Pert, the cuboid (anat., 

cucullate (ku'kulat) a. [L. cucullus, 

a cap.] With hood-like sepals or 
petals (bot.} with prothorax hood- 
shaped (zool.}. 

cuirass (kwe'ras, kweras') n. [F. 
cuirasse, a leathern jacket.] Bony 
plates or scales arranged like a 
cuirass (zool.}. 

culm (kulm) n. [L. culmus, a stalk.] 
The stem of grasses and sedges 

culmen (kul'mgn) n. [L. cellere, to 
push.] The ridge of a bird's beak 
(zool.} ; the anterior raised part of 
the monticulus (anat.}. 

cultellus (kulteTus) n. [L. cultellus, 
a little knife.] A sharp knife-like 
organ, one of the mouth-parts of 
certain blood-sucking flies (zool.}. 

culture (kul'tur) n. [L. colere^ to till.] 
The cultivation of micro-organisms 
in prepared media (bad.}. 

cumulus (ku'mulus) n. [L. cumulus, 
a heap.] The corona radiata (erne.). 

cuneate (ku'neat) a. [L. cuneus, a 
wedge.] Wedge-shaped ; appl. 
leaves with broad abruptly-pointed 
apex, and tapering to the base 

cuneiform (kune'ifonn) a. [L. cuneus, 
a wedge ; forma, shape.] Pert, the 
distal tarsal bones (anat.}. 

cuneus (ku'neus) n. [L. cuneus, a 
wedge.] A division of the elytron 
of certain insects (zool.} ; a wedge- 
shaped area between the calcarine 
fissure and the medial part of the 
parieto-occipital fissure (anat.}. 

cup (kup) n. [A.S. cuppe, a cup.] 
Any structure resembling a cup 

cupula (ku'pula) n. [L. cupula, a 
little tub.] The bony apex of the 
cochlea ; the apex of the lungs 

cupule (kup'ul) n. [L. cuppa, a cup.] 
The involucre of the female flower 
of the oak, etc. ; the gemmae - 
bearing cup of Marchantia (bot.} ; 
a small sucker of various animals 

curviserial (kur' vise' rial) a. [L. cutvus, 
a curve ; series, a row.] Appl. 
phyllotaxis in which the divergence 
is such that the orthostichies them- 
selves are slightly twisted spirally 

cushion (koosh'un) n. [M.E. cuisc/ten, 




a cushion.] The central thick 
region in the prothallus of a fern 

cusp (kusp) n. [L. cuspis, a point.] 
A prominence, as on teeth (anat.) ; 
a sharp point (bot.}. 

cuspidate (kus'pidat) a. [L. cuspidare, 
to make pointed.] Terminating in 
a point ; appl. leaves (hot.) ; pointed ; 
appl. teeth (zool.\ 

cutaneous (kuta'neus) a. [L. cutis, 
the skin.] Pert, the skin. 

cuticle (ku'tlkl) n. [L. cutis, skin.] 
An outer skin or pellicle (zool., 
anat.} ; the epidermis (bot.}. 

cuticular (kutik'ular) a. [L. cutis, 
skin.] Pert, the cuticle or external 

cuticular transpiration, transpira- 
tion through the cuticle, of gases, 
etc. (phys.}. 

cutin (ku tin) n. [L. cutis, skin.] A 
substance allied to cellulose found 
in the external layers of the 
thickened epidermal cells (bot.}. 

cutinization (ku'tlnlza'shun) n. [L. 
cutis, skin.] The deposition of 
cutin in the external cells, thereby 
forming a cuticle (bot.}. 

cutis (ku'tls) n. [L. cutis, skin.] The 
corium, or deeper layer of the skin 

Cuvierian organs (kuve'rlan), 
glandular tubes extending from the 
cloaca of Holothurians (zool.}. 

cyanic (slan'fk) a. [Gk. kyanos, dark 
blue.] Appl. flowers of a blue 
colour (bot.}. 

cyanophilous (slanof'ilus) a. [Gk. 
kyanos, blue ; philein, to love.] 
With special affinity for blue or 
green dyes ; appl. a structure in a 
cell (zool.}. 

cyanophyll (slan'ofil) n. [Gk. kyanos, 
blue ; phyllon, a leaf.] A bluish- 
green colouring matter in plants 

cyathlum (slath'ium) n. [Gk. kyathos, 
a cup.] The peculiar inflorescence 
in Euphorbia, a cup-shaped in- 
volucre with marginal glandular 
scales, and inside, stamens and a 
stalked gynoecium, each stamen 
and the gynoecium being a separate 
flower (bot.}. 

cyathozooid (sl'athozo'oid) n. [Gk. 
kyathos, cup ; soon, animal ; eidos, 

shape.] The primary zooid in 
certain Tunicates (zool.}. 

cyathus (sl'athus) n. [Gk. kyathos, a 
cup.] A small cup-shaped organ ; 
the gemma-cup of Marchantia (hot.}. 

cycle (sl'kl) n. [Gk. kyklos, a circle.] 
The circulation of a fluid through a 
definite series of vessels (anat.}. 

cyclic (si'klik) a. [Gk. kyklos, a circle.] 
Having the parts of the flower 
arranged in whorls (bot.}. 

cyclical (si'klikal) a. [Gk. kyklos, a 
circle.] Cyclic. 

cyclocoelic (si'klose'lik)a. [Gk. kyklos, 
a circle ; koilia, intestines.] With 
the intestine coiled in one or more 
distinct spirals (zool.}. 

cyclogenous (slklqj'enus) a. [Gk. 
kyklos, a circle ; genos, offspring.] 
Exogenous ; appl. a stem growing 
in concentric circles (bot.}. 

cycloid (sl'kloid) a. [Gk. kyklos, a 
circle ; eidos, shape.] Appl. scales 
whose free border presents an even 
curve (zool.}. 

cyclosis (slklo'sls) n. [Gk. kyklosis, a 
whirling round.] The movement 
or circulation of protoplasm within 
a cell (biol.}. 

cyclospermous(sl'kl6sper'mus)a. .[Gk. 
kyklos, a circle ; sperma, a seed.] 
With embryo coiled in a circle or 
spiral (bot.}. 

cyclospondylic (sl'klospondifik) a. 
[Gk. kyklos, a circle ; sphondylos, a 
vertebra.] Appl. centra in which 
the internal calcareous matter is 
confined to the middle zone (zool.}. 

cylinder (sll'inder) n. [Gk. kylindros, 
a cylinder.] Any region marked 
by definite tissue (bot.}. 

cylindrical (silin'drikal) a. [Gk. 
kylindros, a cylinder.] Appl. leaves 
rolled on themselves, or to solid 
cylinder-like leaves (bot.}. 

cymbiform (sim'blform) a. [L. cymba, 
a boat ; forma, shape.] Boat- 

cyme (sim) n. [L. cyma, a young 
sprout of cabbage.] Any deter- 
minate inflorescence (bot.}. 

cynarrhodium (slnaro'dlum), cynar- 
rhodon (slnaro'don) . [Gk. kyon, 
a dog ; rhodon, a rose.] An etaerio 
with the achenes placed on a con- 
cave thalamus (bot.}. 

cynopodous (smop'odus) a. [Gk. 




kyon, a dog ; pous, a foot.] With 
non-retractile claws (zoo/.). 

cyphella (slfeTa) n. [Gk. kyphella, 
hollow of the ear.] A small cup 
found on the thallus of certain 
Lichens (dot.). 

cypsela (sip'sela) n. [Gk. kypsele, a 
hollow vessel.] An inferior bi- 
carpellary achene (dot,). 

cyst (sist) n. [Gk. kystis, a bladder.] 
The enclosing membrane (as distinct 
from the protoplasm) around a 
resting cell or apocyte (zoo/.) ; a 
bladder or air vesicle in certain 
Seaweeds (dot.). 

cystein (sis'tein) . [Gk. kystis, a 
bladder.] A proteid decomposition 
product (phys.). 

cystenchyma (sisteng'kima) n. [Gk. 
kystis, a bladder ; engchyma, in- 
fusion.] A parenchyma in sponges 
with large vesicular cell-structure 

cystencytes (sis'te"nslts) n. flu. [Gk. 
kystis, a bladder ; kytos, hollow.] 
In sponges, collencytes which have 
acquired a vesicular structure 

cystic (sls'tlk) a. [Gk. kystis, a bladder.] 
Pert, a cyst (dial.) ; pert, the gall or 
urinary bladder (anat.). 

cysticercoid (sis'tiseYkoid) a. [Gk. 
kystis, a bladder ; kerkos, a tail ; 
eidos, form.] Appl. the bladder- 
worm stage of tape-worms (zoo/.). 

cysticercus (sis'tiser'kus) n. [Gk. 
kystis, a bladder ; kerkos, a tail.] 
The larval form or bladderworm 
stage of certain tape-worms (zoo/.). 

cysticolous (sistik'blus) a. [Gk. kystis, 
a bladder ; L. colere, to inhabit.] 
Living in a cyst (zoo/.). 

cystid (sis'tld) n. [Gk. kystis, a 
bladder.] A fossil form of any of 
the Cystoidea (pal.). 

cystidium (sistid'ium) n. [Gk. kystis, 
a bladder.] A large inflated cell in 
the hymenial layer of some Fungi 

cystoarian (sis'toa'rlan) a. [Gk. kystts, 
a bladder.] Appl. gonads when 
they are enclosed in coelomic sacs, 
as in most Teleosts ; opp. gymno- 
arian (zoo/.). 

cystocarp (sis'tbkarp) n. [Gk. kystis, 
a bladder ; karpos, fruit.] Crypto- 
carp, which see. 

cystocyte*(srs't6sit) n. [Gk. kystis, a 
bladder ; kytos, hollow.] Cysten- 
cyte, which see. 

cystogenous (sistoj'Snus) a. Gk. 
kystis, a bladder ; genos, offspring.] 
Cell-forming ; appl. large nucleated 
cells in the cercaria of Distomum 
which secrete the cyst (zoo/.).' 

cystolith (sis'tolith) n. [Gk. kystis, a 
bladder ; lithos, a stone.] An ir- 
regular mass of calcium carbonate 
found in epidermal cells, as in the 
nettle (dot.). 

cyston (sis'ton) n. [Gk. kystis, a 
bladder.] A dactylozooid in the 
Siphonophora modified for excre- 
tory purposes (zoo/.). 

cytase (sl'tas) n. [Gk. kytos, hollow.] 
An enzyme responsible for digesting 
hemi-celluloses (dot.). 

cytaster (sltas'tgr) n. [Gk. kytos, 
hollow ; aster, a star.] A star- 
shaped achromatinic figure consist- 
ing of the attraction-sphere and 
aster rays (cyt.). 

cytoblast (sftoblast) n. [Gk. kytos, 
hollow ; dlastos, a bud.J The cell 
nucleus ; one of the hypothetical 
vital units of which a cell is formed 

cytoblastema (sl'tbblaste'ma) n, [Gk. 
kytos, hollow ; blastema, growth.] 
The formative material from which 
cells were supposed to arise 

cytochylema (sl'toklle'ma) n. [Gk. 
kytos, hollow ; chylos, juice.] Cyto- 
lymph, which see. 

cytococcus (sl'tokok'us) n. [Gk. kytos, 
hollow ; kokkos, a grain.] The 
nucleus of a fertilized egg (zoo/.). 

cytocyst (si'tosist) n. [Gk. kytos, 
hollow; kystis, a bladder.] The 
envelope formed by the remains 
of the host - cell within which 
the protozoan parasite multiplies 

cytode (sl'tod) . [Gk. kytos, hollow ; 
eidos, form.] A non - nucleated 
protoplasmic mass (cyt.). 

cytodiaeresis (sl'todie'rgsTs) n. [Gk. 
kytos, hollow ; diairesis, division.] 

cytogamy (sltbg'aml) n. [Gk. kytos, 
hollow ; gatnos, union.] Conjuga- 
tion (zoo/.). 

cytogenesis (sftojen'SsIs) n. [Gk. 




kytos, hollow ; genesis, descent.] 
The development or formation of 
cells (biol.). 

cytogenous (sltoj'gnus) a. [Gk. kytos, 
hollow ; genos, offspring.] Produc- 
ing cells ; appl. lymphatic tissue 

cytoglobin (si'toglo'bm) n. [Gk. kytos, 
hollow ; L. globus, a globe.] A 
proteid which retards coagulation 
of the blood (phys.). 

cytohyaloplasma (sl'tohi'aloplaz'ma) 
n. [Gk. kytos, hollow ; hyalos, glass ; 
plasma, something moulded.] The 
substance of the cytomitome 

cytology (sltol'oji) n. [Gk. kytos, 
hollow ; logos, discourse.] The 
branch of biology dealing with the 
structure, functions, and life-history 
of cells. 

cytolymph (sl'tolimf) n. [Gk. kytos, 
hollow ; L. lympha, water.] The 
ground -substance of cytoplasm 

cytolysin (sl'toll'sin) n. [Gk. kytos, 
hollow ; lysis, a loosing.] A sub- 
stance inducing cytolysis (phys.). 

cytolysis (sltol'isis) n. [Gk. kytos, 
hollow ; lysis, a loosing.] Cell-dis- 
solution ; cell-degeneration (phys.). 

cytomeres (sftomerz) n. plu. [Gk. 
kytos, hollow ; meros, a part.] The 
cells in Carystropha formed by the 
division of the schizont, and them- 
selves giving rise to the merozoites 

cytomicrosome (si'toml'krosom) n. 
[Gk. kytos, hollow ; mikros, small ; 
soma, body.] A microsome of the 
cytoplasm ; opp. nucleomicrosome 

cytomitome (si'tomitom) n, [Gk. 
kytos, hollow ; mitos, a thread.] 
The cytoplasmic threadwork (cyt.). 

cytomorphosis (sl'tb'mor'fosTs, sl'to- 
morfo'sis) n. [Gk. kytos, hollow ; 
morphosis, a shaping.] The life- 
history of cells ; the series of 
structural modifications of cells or 
successive generations of cells 

cyton (si'ton) n. [Gk. kytos, hollow.] 
The body of a nerve cell (phys.). 

cytophan (sl'tofan) n. [Gk. kytos, 
hollow ;phaneros, visible.] The ovoid 
matrix surrounding the karyophans 

in the spironeme and axoneme 
fibres in the stalk of an Infusorian 

cytopharynx (sl'tdfar'ingks) n. [Gk. 
kytos, hollow ; pharyngx, the gullet.] 
A tube-like structure leading from 
the mouth into the endoplasm in 
certain protozoan cells (zool.). 

cytophil (si'tofil) a. [Gk. kytos, 
hollow ; philein, to love.] Pert. 
haptophorous groups ; having an 
affinity for cells (phys.). 

cytoplasm (si'toplazm) n. [Gk. kytos, 
hollo w;^/<z.r;#<z,something moulded.] 
The substance of the cell-body ex- 
clusive of the nucleus ; cf. nucleo- 
plasm (cyt.}. 

cytoproct (sl'toprokt) n. [Gk. kytos, 
hollow ; proktos, anus.] A cell- 
anus (zool.}. 

cytopyge (si'toplj) n. [Gk. kytos, 
hollow ; pyge, the rump.] Cyto- 
proct, which see. 

cytoreticulam (sl'toretik'ulCim) n. 
[Gk. kytos, hollow ; L. reticulum, a 
little net.] The cytoplasmic thread- 
work (cyt.). 

cytosine (sl'tosin) n. [Gk. kytos, 
hollow.] A cleavage product of 
protein (phys). 

cytosome (sltosom) n. [Gk. kytos, 
hollow ; soma, body.] The body of 
the cell as opposed to that of the 
nucleus (cyt.). 

cytostome (sl'tostom) . [Gk. kytos, 
hollow ; stoma, a mouth.] A cell- 

cytotaxls (sl'totak'sis) n. [Gk. kytos, 
hollow ; taxis, arrangement.] Cy- 
totropism, which see. 

cytothesis (sitoth'esis) n. [Gk. kytos, 
hollow ; thesis, something set down.] 
The regenerative tendency of a cell 
or neuron (phys.). 

cytotoxin (sl'totok'sin) n. [Gk. kytos, 
hollow ; toxikon, poison.] A cell- 
poisoning substance formed in the 
blood serum (phys.). 

cytotrophoblast (si'totro'foblast) n. 
[Gk. kytos, hollow ; trophe, nourish- 
ment ; blastos, a bud.] The inner 
layer of the trophoblast, or layer of 
Langhans (anat.). 

cytotroplsm (sltot'roptzm) n. [Gk. 
kytos, hollow ; trope, a turning.] 
The mutual attraction of two or 
more cells (cyt.). 




cytozoic (sftozolk) a. [Gk. kytos, 
hollow ; zoon, an animal.] Appl. 
the trophozoite of a sporozoon when 
situated within a cell (zool.}. 

cytula (sit'ula) n. [Gk. kytos, hollow.] 
The fertilized ovum or parent cell 


dacryon (dak'rlon) n. [Gk. dakryon, 
tear.] The point of junction of the 
anterior border of the lacrimal with 
the frontal (anat.}. 

dactyl (dak'til) n. [Gk. daktylos, 
finger.] A digit or finger (anat.}. 

dactylar (dak'tilar) a. [Gk. daktylos, 
finger.] Pert, finger or digit (anat.}. 

dactylopodite (dak'tllop'odlt) n. [Gk. 
daktylos, finger ; pous, foot.] The 
distal joint in certain limbs in the 
Crustaceans, especially the thoracic 
limbs (zool.}. 

dactylopore (dak'tllopor') n. [Gk. 
daktylos, finger ; poros, exit.] The 
opening in the skeleton of the 
Milleporina through which a dactyl- 
ozooid protruded when alive (zool.'). 

dactylopterous (dak'tllop'te'rus) a. 
[Gk. daktylos, finger ; pteron, wing.] 
With the anterior rays of the 
pectoral fins more or less free 

dactylozooid (dak'tilozo'oid) n. [Gk. 
daktylos, finger ; zoon, animal ; 
eidos, resemblance.] A hydroid 
modified for the special function of 
catching prey, it may be long, with 
tentacles or with short knobs, with 
or without a mouth (zool.). 

dactylus (dak'tilus) n. [Gk. daktylos, 
finger.] Part of the tarsus of an 
insect (zool.}. 

dart (dart) n. [O.F. dart, dagger.] 
Anything resembling a dart, appl. 
crystalline structure in Molluscs 

dart sac, a small sac containing a 
dart of limey material attached to 
the vagina near its orifice in Gastro- 
pods (zool.}. 

dartoid (dar'toid) a. [Gk. dartos, 
flayed.] Pert, the dartos (anat.}. 

dartos (dar'tSs) n. [Gk. dartos, 
flayed.] A thin layer of non-striped 

muscle fibres around the base of 
the scrotum (anat.}. 

Darwinian tubercle, theslightprom- 
inence on the helix near the point 
where it bends downwards (anat.}. 

Darwinism (Dar'wlnlzm) n. [Dar- 
win.] The theory of the origin of 
species by natural selection working 
on the slight variations that occur, 
thereby selecting those fittest to 
survive (biol.}. 

dasypaedes (da'sipe'dez) n. phi. [jGk. 
dasys, hairy ; pats, child.] Birds 
whose young are downy at hatching 

daughter (d6'ter) n. [A.S. dohtor, 
daughter.] Offspring of the first 
generation with no reference to sex, 
as daughter-cell, daughter-nucleus, 
etc. (biol.}. 

deamlnation (deam'inashun) n. [L. 
de, down ; Gk. amtnoniacum, a 
resinous gum.] The conversion of 
ammonium salts into urea, partly 
accomplished in the liver (phys.}. 

death (deth) n. [M.E. deth, death.] 
The complete and permanent cessa- 
tion of all vital functions in any 
organism (biol.}. 

death-point, the temperature above 
or below which micro-organisms 
cannot exist (biol.}. 

decalcify (dekal'sifl) v. [L. de, away ; 
calx, lime.] To treat with acids for 
the removal of the calcareous part 

decamerous (dgkam'griis) a. [Gk. 
deka, ten ; meros, part.] With the 
various parts arranged in tens (bot.}. 

decapod (dek'apod) a. [Gk. deka, 
ten ; pous, foot.] In Crustacea, 
with five pairs of legs on the 
thorax ; in Cephalopods, with ten 
arms (zool.}. 

decapodlform (dek'apod'iform) a. [Gk. 
deka, ten ; pous, foot ; L. forma, 
shape.] Resembling a decapod, 
usually said of insect larvae (zool.}. 

decemfid (dgsfim'fid) a. [L. decent, 
ten ; findere, to cleave.] Cut into 
ten segments (bot.}. 

decemfoliate (des'gmfo'liat) a. [L. 
decent, ten ; folium, leaf.] Ten- 
leaved (bot.}. 

decemjugat (deVmjoo'gat) a. [L. 
decem, ten ; jugare, to join.] With 
ten pairs of leaflets (bot.}. 




decempartite (dgs'e'mpar'tit) a. [L. 
decem, ten ; partiri, to divide.] Ten- 
lobed ; divided into ten lobes (dot.). 

decidua (desid'ua) n. [L. de, away ; 
caderc, to fall.] The mucous mem- 
brane lining the uterus, that is cast 
off after parturition (anat.). 

decidual (desid'ual) a. [L. de, away ; 
cadere, to fall.] Pert, decidua 

deciduate (desld'uat) a. [L. de, away ; 
cadere, to fall.] Characterized by 
having a decidua ; partly formed 
by the decidua (zoo/.). 

deciduous (desid'uus) a. [L. de, away ; 
cadere, to fall.] Falling at the end 
of the period of growth (dot.} ; falling 
at maturity (zoo/.). 

declinate (dek'ltnat) a. [L. de, away ; 
clinare, to bend.] Bending aside 
in a curve, as the anther filament 
in the horse-chestnut (dot.). 

decollated (dekol'ated) a. [L. de, 
away ; collum, neck.] With the 
apex of the spire wanting (zoo/.). 

decomposed (de'kompozd') a. [L. de, 
away ; cum, with ; ponere, to place.] 
Not in contact ; not adhering, said 
of the barbs of a feather when they 
are separate (zoo!.). 

decompound (de'kompound') a. [L. 
de, away ; cum, with ; ponere, to 
place.] When the monopodial 
branching is very complete, and 
the ultimate wings are little de- 
veloped, the leaf is called decom- 
pound (dot.}. 

decumbent (dekum'bent) a. [L. de- 
cumbere, to lie down.] Appl. stems 
which trail on the ground, but rise 
at the apex (A?/.).. 

decurrent (dekuYSnt) a. [L. de, 
away ; currere, to run.] Having the 
leaf base prolonged down the stem 
as a winged expansion or rib (hot.}. 

decussate (dgk'usat, dekus'at) a. [L. 
decussare, to cross like an X.] 
Having paired leaves, succeeding 
pairs crossing at right angles (dot.}. 

decussation (de'kusa'shun) n. [L. 
decussare, to cross like an X.] The 
condition when opposite leaves are 
arranged so that each pair crosses the 
previous at right angles (dot.} ; the 
crossing of nerves or bands of 
nerve-fibres when there is an inter- 
change of fibres (anat.). 

dedupllcation (dedu'plika'shun) . 
[L. de, intensive ; duplicare, to 
double.] The augmentation of 
parts of a flower by splitting during 
development (dot.}. 

defaecation (de'feka'shun) n. [L. 
defaecatio, voiding of excrement.] 
The expulsion of faeces (phys.}. 

defensive (defen'siv) a. [L. defendere, 
to defend.] Protective ; appl. pro- 
teid substances which destroy the 
toxic substances of bacteria (phys.) ; 
appl. numerous organs or parts of 
organs in various animals (zoo/.). 

deferred (defgrd') a. [L. deferre, to 
bring down.] Appl. shoots that are 
given out from dormant buds when 
stem or branch has been destroyed 

definite (def'Tnlt) a. [L. definire, to 
limit.] Fixed, constant ; appl. 
inflorescences with primary axis 
terminating early in a flower ; appl. 
stamens limited to twenty in number 

definitive (defin'itiv) a. [L. definire, 
to limit.] Complete, fully developed 

defoliate (defo'liat) a. [L. defoliare, 
to strip of leaves.] Bared at the 
annual fall (dot.}. 

degeneration (dejgnera'shun) n. [L. 
degener, base.] Return to a simpler 
condition ; retrogressive evolution 

deglutition (deglootish'un) . [L. 
deglutire, to swallow down.] The 
process of swallowing (phys.}. 

dehiscence (dehls'gns) n. [L. de, 
away ; hiscere, to gape.] The 
opening of an organ or structure 
along certain lines or in a definite 
direction (dot.}. 

Deiter's cells (di'tgrz), supporting 
cells between the rows of outer 
hair-cells in the organ of Corti 

delamination (delam'inashun) n. [L. 
de, down ; lamina, a layer.] The 
dividing off of cells to form new 
layers (emd.). 

deliquescent (del'ikwes'ent) a. [L. 
deliquescere, to become fluid.] 
Having the lateral buds the more 
vigorously developed so that the 
main stem seems to divide into a 
number of irregular branches (dot.). 




delomorphous (de'lomor'fus) a. [Gk. 
delos, visible ; morphe, shape.] With 
definite form, appl. oxyntic cells of 
the gastric glands (anat.). 

delthyrium (dglthl'rium) n. [Gk. 
delos, visible ; thyrion, little door.] 
The opening between the hinge 
and beak for the peduncle exit in 
many Brachiopods (zoo/.). 

deltidium (deltld'ium) n. [Gk. A, 
delta.] A plate covering the del- 
thyrium (zoo/.). 

deltoid (deftoid) a. [Gk. A, delta; 
eidos, resemblance.] More or less 
triangular in shape, appl. nerves, 
muscles, etc. (anat.} ; appl. the oral 
Mates on the calyx of the Blastoids 

plates ( 

demersal (demeYsal) a. [L. demer- 
gere, to demerse.] Sunk ; appl. fish 
eggs which sink to the bottom 

deiniplate (dem'iplat) n. [L. dimidius, 
half ; platus, flat.] Plate cut off by 
the fusion of adjoining plates behind 
it from the central suture line of the 
ambulacral area in Echinoderms 

demisheath (dgm'Isheth) n. [L. 
dimidius, half; A.S. sceath, sheath.] 
One of the protecting covers of the 
ovipositor (zoo/.). 

demoid (de'moid) a. [Gk. demos, the 
common people.] Abundant (pal.). 

dendriform (den'driform) a. [Gk. 
dendron, tree ; L. forma, shape.] 
Tree-like (dial.). 

dendrite (dSn'drit) n. [Gk. dendron, 
tree.] A branched tree-like proto- 
plasmic process of a nerve cell 

Dendrogaea (dSn'droje'a) n. [Gk. 
dendron, tree ; gaia, earth.] A zoo- 
geographical region, including all 
the Neotropical region except 
temperate South America (bio/.). 

dendron (deVdron) n. See dendrite. 

dens(denz)w. [L. dens, tooth.] Tooth, 
or tooth-like process (anat.). 

dental (den'tal) a. [L. dens, tooth.] 
Pert, teeth ; appl. nerves, blood- 
vessels, canals, furrows, papillae, 
tissue, etc. (anat.). 

dentary (den'tari) a. [L. dens, tooth.] 
Pert, dentaries, membrane bones in 
lower jaw of many vertebrates 

dentate (dgn'tat) a. [L. dens, tooth.] 
With sharp saw-like teeth on the 
margin (zoo/., dot.). 

dentate ciliate, with teeth and hairs 
on the margins ; appl. leaves 

dentate crenate, with marginal teeth 
somewhat rounded (dot.). 

denticles (den'tiklz) n. plu. [L. dens, 
tooth.] The paragnaths of certain 
Polychaets ; the teeth within the 
secondary orifice in Polyzoa ; the 
scales of certain Elasmobranchs 

dentinal (den'tinal) a. [L. dens, tooth.] 
Pert, dentine (anat.). 

dentine (dgn'tin) n. [L. dens, tooth.] 
A hard, highly elastic substance 
composing the greater part of every 
tooth, a collagen (anat.). 

dentition (dgntish'un) n. [L. dens, 
todth.] The number, arrangement, 
and kind of teeth in the jaws of an 
animal (anat.). 

depigmentation (depTg'me'nta'shun) n. 
[L. de, away ; pingere, to paint.] 
The destruction of colour in a cell, 
either by natural or experimental 
physiological processes (phys.). 

deplanate (dep'lanat) a. [L. deplan- 
are, to level.] Levelled, flattened 

depressant (depres'ant) n. [L. de- 
priinere, to lower.] Anything that 
lowers vital activity (phys.). 

depressed (deprgst') a. [L. deprimere, 
to lower.] Flattened in a vertical 
direction (diol.). 

depressomotor (deprSs'omo'tor) n. 
[L. deprimere, to lower ; movere, to 
move.] Any nerve which lowers 
muscular activity (anat.). 

depressor (depreVor) n. [L. depri- 
mere, to lower.] Any muscle which 
lowers or depresses any structure; 
appl. a nerve which lowers the 
activity of an organ (anat.). 

derm (dSrm) . [Gk. derma, skin.] 
The layers of the integument below 
the epidermis (anat.). 

derma (deYma) n. See derm. 

dermal (der'mal) a. [Gk. derma, 
skin.] Pert, derma, or skin (anat.). 

dermalia (deYma'lia) n. plu. [Gk. 
derma, skin.] Microscleres in the 
dermal membrane in Sponges 




dermarticulare (deVmartTk'ula're, 
-ara) n. [Gk. derma, skin ; L. 
articulare, to divide into joints.] 
The goniale (zoo/.). 

derrnatogen (der'matqje'n) n. [Gk. 
derma, skin ; gignesthai, to produce.] 
The young or embryonic epidermis 
in plants (bo/.). 

dermatoplasm (deVmatoplazm') n. 
[Gk. derma, skin ; plasma, some- 
thing moulded.] The cell-wall 
protoplasm (bol.). 

dermatoplast (deVmatoplast') n. [Gk. 
derma, skin ; plastos, moulded.] A 
protoplast with a supposed cell-wall 

dermatopsy (deYmatop'si) n. [Gk. 
derma, skin ; ^^w, sight.] Condi- 
tion of seeing with the skin, i.e. 
with a skin sensitive to light (zoo/.). 

dermatosome (deVmatosom') . [Gk. 
derma, skin ; soma, body.] One of 
vital units forming a cell-membrane 

dermic (der'mik) a. [Gk. derma, 
skin.] Pert, skin, or derived from 
the skin (zoo/.). 

dennis (deYmis) n. [Gk. derma, 
skin.] See derm. 

dermoblast (der'moblast') n. [Gk. 
derma, skin ; blastos, bud.] The 
layer of mesoblast which gives rise 
to the derma (anat.). 

dermoossification (deVmoos'ifika'- 
shun) n. [Gk. derma, skin ; L. 
os, bone ; fieri, to become.] A 
bone formed in the skin (zoo/.). 

dermosclerites (deVmoskleYfts) n.plu. 
[Gk. derma, skin ; skleros, hard.] 
Masses of spicules found in the 
tissues of the Alcyonidae (zoo/.). 

dermoskeleton (deYmoskeTe'ton) n. 
[Gk. derma, skin ; skeletos, dried.] 
See exoskeleton. 

dertrotheca (deYtrothe'ka) n. [Gk. 
dertron, beak ; theke, cup.] The 
horny casing of the maxilla of 
birds (zoo/.). 

dertrum (deVtrum) n. [Gk. dertron, 
beak.] Any modification of the 
casing of the maxilla in birds 

descendence (desSn'dSns) n. [L. de, 
down ; scandere, to climb.] Descent 
from some ancestor, usually a 
common ancestor (biol.). 

descending (desen'ding) a. [L. de, 

down ; scandere, to climb.] Directed 
towards the caudal region ; appl. 
blood-vessels, nerves, etc. (ana/.). 

desegmentation (deseg'me'nta'shun) 
n. [L. de, from ; segmentum, piece 
cut off.] Fusion of segments origin- 
ally separate (zoo/.). 

deserticolous (de"zertlk'6lus) a. [L. 
desertus, solitary ; colere, to inhabit.] 
Desert-inhabiting (zoo/.). 

desma (des'ma) n. [Gk. desma, bond.] 
The megasclere which forms the 
characteristic skeletal network of 
the Lithistida, an irregular branched 
spicule (zoo/.). 

desmactinic (des'maktm'ik) a. [Gk. 
desma, bond ; aktis, ray.] With 
the podia continued upwards to 
the apical plate, appl. Stelleroidea ; 
cf. lysactinlc (zoo/.). 

desmogen (des'mqjen) n. [Gk. desma, 
bond ; gignesthai, to produce.] 
Merismatic tissue (bot.). 

desmognathous (desmog'nathus) a. 

eik. desma, bond ; gnathos, jaw.] 
aving the maxillo-palatines fused 
with one another in the middle line 
owing to certain other peculiarities 
in the skull ; appl. birds (zoo/.). 

desquamation (des'kwama'shun) n. 
[L. de, away ; squama, scale.] The 
shedding of the cuticle or epidermis 
in flakes (zoo/.). 

determinant (deter'mmant) n. [L. 
determinare, to limit.] A hypo- 
thetical unit, being an aggregation 
of biophores determining the de- 
velopment of a cell or an inde- 
pendently variable group of cells 

determinate (deter'minat) a. [L. 
determinare, to limit.] With certain 
limits ; appl. inflorescence with the 
primary axis terminated early with 
a flower-bud (bot.) ; appl. cleavage 

detorsion (detor'shun) n. [L. de, 
away ; torquere, to twist.] Torsion 
in an opposite direction to that 
of the original, resulting in a more 
or less posterior position of the 
anus and circumanal complex (zoo/.). 

deuterocerebrum (du'terb'se'r'e'brum) 
n. [Gk. deuteros, second ; kerebron, 
brain.] That portion of the Crusta- 
cean brain from which the anten- 
nular nerves arise (zoo/.). 




deuterocone (du'tgrokon') n. [Gk. 
deuteros, second ; konos, cusp.] 
A mammalian premolar cusp 
corresponding to the molar pro- 
tocone (anat). 

deuteroproteose (du'tgropro'tSos) n. 
[Gk. deuteros, second ; protein, to 
be first.] A secondary product 
from the gastric and pancreatic 
digestion of proteids (phys). 

deuterostoma (du'tgrosto'ma) n. [Gk. 
deuteros, second ; stoma, mouth.] 
A mouth formed secondarily, as 
distinct from the gastrula mouth 

deuterotoky (du'teVot'ok!) n. [Gk. 
deuteros, second ; tokos, birth.] 
Reproduction of both sexes from 
parthenogenetic eggs ; cf. arrheno- 
toky and thelyotoky (zool). 

deuterozooid (du'tSrozo'oid) n. [Gk. 
deuteros, second ; zoon, animal ; 
eidos, resemblance.] A zooid 
produced by budding from a 
primary zooid (zool). 

deuthyalosome (duthi'alosom) n. [Gk. 
deuteros, second ; hyalos, glass ; 
soma, body.] The nucleus remain- 
ing in the ovum after the formation 
of the first polar body (cyt.). 

deutoblast (du'toblast) n. [Gk. 
deuteros, second ; blastos, bud.] 
The amoeba-like bodies formed 
from the protoblasts in the zygote 
of Microclossia, and liberated to 
multiply in the blood (zool.}. 

deutocerebron (du'toseVSbron) n. 
[Gk. deuteros, second ; kerebron, 
brain.] That portion of the brain 
of certain insects which corre- 
sponds with the deuterocerebrum 
of Crustaceans (zool.} ; also deuto- 

deutomalae (du'toma'le, -mal'a) n. plu. 
[Gk. deuteros, second ; malon, 
cheek.] The broad plate in the 
Chaetognatha covering the under 
part of the head and partially 
enclosing the mouth, formed by 
the fusion of the second pair of 
mouth appendages (zool.). 

deutomerite (dutom'e'rit) n. [Gk. 
deuteros, second ; meros, part.] 
The posterior division of a Greg- 
arine body (zool.). 

deutoplasm (dii'toplazm) n. [Gk. 
deuteros, second ; plasma, some- 

thing moulded.] The yolk or 
food material in the cytoplasm of 
an ovum ; opp. protoplasm (cyt.). 

deutoscolex (du'tosko'lgks) n. [Gk. 
deuteros, second ; skolex, head.] 
A secondary scolex produced by 
budding, in the bladder-worm stage 
of certain tape-worms (zool.). 

deutovum(duto'vum) n. \Gk.deuteros, 
second ; L. ovum, egg.] A stage 
in the metamorphosis of certain 
mites in which the outer envelope 
becomes brown and hard, and 
splits longitudinally, exposing the 
thin inner membrane (zool). 

development (deveTo'pme'nt) n. [F. 
developper, to unfold.] The changes 
undergone by an organism on reach- 
ing maturity (biol). 

dexiotropic (dgk'slotrop'ik) a. [Gk. 
dexios, right ; trepein, to turn.] 
Having the whorls turning from 
left to right ; appl. shells (zool.) ; 
appl. spiral cleavage (cyt.). 

dextral (deYstral) a. [L. dexter, 
right-hand.] See dexiotropic. 

dextrin (dek'strin) n. [L. dexter, 
right-hand.] A soluble substance 
derived from starch by exposure 
to a high temperature for a short 
time (phys). 

dextrorse (dekstrors', dSk'strors) a. 

g.. dexter, right ; vertere, to turn.] 
rowing in a spiral which twines 
from left to right (hot). 

diachaenium (di'ake'nlum) n. [Gk. 
dis, twice ; a, not ; chanein, to 
gape.] Each part of a cremocarp 

diacranteric (dl'akranteVik) a. [Gk. 
dia, asunder ; kranteres, wisdom 
teeth.] With a diastema between 
the front and back teeth, as in 
snakes (zool). 

diactinal (dlak'tinal) a. [Gk. dis, 
twice ; aktis, ray.] With two rays 
pointed at the ends (zool). 

diadelphous (dl'SdeTfus) a. [Gk. dis, 
twice ; adelphos, brother.] Having 
the stamens in two bundles owing 
to the fusion of the filaments 

dladematoid (dl'adgm'atoid) a. [Gk. 
diadema, crown ; eidos, shape.] Of 
Echinoids, having the pore plates 
arranged as follows : three prim- 
aries with occasionally a secondary 




between the aboral and the middle 
primary (zool.). 

dladromous (dl'adro'mus) a. [Gk. 
diadromos, wandering.] Having 
the nerves radiating in a fan-like 
manner (dot.}. 

diaene (dlen') n. [Gk. dis, twice on 
analogy of triaene, from Gk. triaina, 
trident.] A form of triaene, with 
one of the cladi reduced or absent 

diageotropism (dl'ajeot'ropizm) n. 
[Gk. dia, through ; gaia, earth ; 
trepein, to turn.] The tendency 
in certain parts of plants to take 
a position at right angles to the 
direction of gravity (dot.}. 

diagnosis (dfagno'sis) n. [Gk. diet, 
through ; gignoskein, to know.] A 
concise description of an organism 
with full distinctive characters 

diagnostic (dl'agnos'tik) a. [Gk. diet, 
through ; gignoskein, to know.] 
Differentiating the species or genus, 
etc., from others similar (biol.}. 

diaheliotropism (dl'ahelTot'ropizm) n. 
[Gk. dia, through ; helios, sun ; 
trepein, to turn.] The tendency of 
certain parts of plants to take up 
a position at right angles to the 
rays of light (&?/.). 

dialyneury (dl'allnu'rl) n. [Gk. dia, 
through ; lyein, to loose ; neuron, 
nerve.] In certain Gastropods, 
having the pleural ganglia united 
to the opposite branch of the 
visceral nerve by an anastomosis 
of the pallial nerve (zool.}. 

dialypetalous (di'alipeYalus) a. [Gk. 
dia, asunder ; lyein, to loose ; 
petalon, petal.] Polypetalous (dot.}. 

dialyphyllous (dl'allfll'us) a. [Gk. 
diet) asunder ; lyein, to loose ; 
phyllon, leaf.] With separate 
leaves (bot.). 

dialysepalous (dl'alisep'alus) a. [Gk. 
dia, asunder ; lyein, to loose ; 
sepalon, sepal.] Polysepalous (bot.}. 

dialystely (dl'aliste'li) n. [Gk. dia, 
asunder ; lyein, to loose ; stele, 
post.] A condition in which the 
steles in the stem remain more or 
less separate (dot.). 

diancistra (di'angkTs'tra) n . [Gk. 
dis, twice ; angkistron, hook.] A 
spicule resembling a stout sigma, 

but the inner margin of both hook 
and shaft thins out to a knife edge 
and is notched (zool.}. 

diandrous (dlan'drus) a. [Gk. dis, 
twice ; aner, man.] Having two 
free stamens (bot.}. 

diapedesis (dlaped'esis, dl'apede'sis) 
n. [Gk. diapedesis, leaping through.] 
Emigration of white blood corpuscles 
through the walls of the capillaries 
into the surrounding tissue (phys.}. 

diaphototropism (di'afotot'ropizm) ;/. 
[Gk. dia, through ; p/ws, light ; 
trepein, to turn.] See diahelio- 

diaphragm (di'afram) n. [Gk. di- 
aphragtna, midriff.] The wall 
which separates the small cell, the 
prothallus, from the rest of the 
macrospore in Hydropterideae ; a 
septum at the nodes in Equisetum 
(bot.} ; a sheet of muscular tissue 
attached to the introvert in worms ; 
the single strongly developed septum 
in the Terebelliformia ; the per- 
forated tissue that subdivides the 
tentacle cavity in Polyzoa ; the 
transverse septum separating the 
cephalothorax from the abdomen 
in certain Arachnids ; a special 
fan-shaped muscle spreading from 
the anterior end of the ilia to the 
oesophagus and base of the lungs 
in Anura ; a partition partly 
muscular, partly tendinous, separat- 
ing the cavity of the chest from the 
abdominal cavity (zool.}. 

diaphragma (dfafrag'ma) n. See 

diaphysis (diaf'ists) n. [Gk. dia, 
through ; phyein, to bring forth.] 
The shaft of a bone as distinguished 
from the epiphysis (anat.} ; the 
abnormal growth of an axis or 
shoot (bot.}. 

diapophysis (di'apof'Ms) n. [Gk. dia, 
through ; phyein, to produce.] The 
lateral or transverse process of the 
neural arches of Anura (zool.}. 

diarch (dl'irk) a. [Gk. dis, twice ; 
arcke, origin.] With two xylem 
and two phloem bundles ; appl. 
root in which the protoxylem 
bundles meet and form a plate of 
tissue across the cylinder with the 
phloem bundle on each side (bot.). 

diarthrosis (dl'arthro'sls) n. [Gk. dia^ 



through ; arthroun, to fasten by a 
joint.] An articulation allowing 
considerable movement (anat.}. 

diastase (dl'astas) n. [Gk. dia, 
through ; histanai, to set.] An 
enzyme which acts principally in 
converting starch into sugar 

diastatic (dl'astat'lk) a. [Gk. diet, 
through ; histanai, to set.] Pert. 
diastase, or having similar prop- 
erties (phys.}. 

diastema (dlas'tgrnS, dl'aste'ma) n. 
[Gk. diastema) space.] A space in 
a jaw without teeth, usually be- 
tween two types of teeth (zool.}. 

diaster (dlas'ter) n. [Gk. dis, twice ; 
aster, star.] The stage in mitosis 
where the daughter chromosomes 
are grouped near the spindle poles 
ready to form a new nucleus (cyt.}. 

diastole (dlas'tole) n. [Gk. diastole, 
difference.] The rhythmical relaxa- 
tion of the heart ; the rhythmical 
expansion of a contractile vacuole 

diastomatic (dl'astom&t'Ik) a. [Gk. 
dia, through; stoma, pore.] Through 
the stomata or pores, giving off 
gases from the spongy parenchyma 
through the stomata (bot.}. 

diathesis (diathesis) n. [Gk. dia, 
through ; tithenai, to place.] A 
congenital predisposition to some 
class of diseases or type of develop- 
ment (biol.}. 

diatom (dl'atom) n. [Gk. dia, through ; 
temnein, to cut.] Any unicellular 
microscopic form of Alga with walls 
of silica (dot.}. 

diatropism (diat'ropizm) n. [Gk. dia, 
through ; trepein, to turn.] The 
tendency of plants or organs of 
plants to place themselves at right 
angles to the line of action of the 
stimulus (bot.}. 

diaxon (dlak'son) a. [Gk. dis, twice ; 
axon, axis.] With two axes, as 
certain sponge spicules (zool.}. 

diaxone (dlak'son) n. [Gk. dis, twice ; 
ax-on, axis.] A nerve-cell with two 
cylinder axes (anat.}. 

diblastula (dlblas'tula) n. [Gk. dis, 
twice ; blastos, bud.] A coelenter- 
ate embryo consisting of two layers 
arranged round a central cavity 

dibranchiate (dlbrangTcTat) a. [Gk. 
dis, twice ; brangchift, gills.] With 
two gills (zool.}. 

dicellate (dlseTat) a. [Gk. dikella, a 
two-pronged hoe.] With two 
prongs ; appl. sponge spicules 

dichasium (dlkaz'Tum) n. [Gk. di- 
chazein, to divide in two.] An 
inflorescence in which two buds 
always develop just below the 
terminal bud (bot.}. 

dichlamydeous (dl'klamld'eus) a. 
[Gk. dis, twice ; chlamys, cloak.] 
Having both calyx and corolla 

dichogamy (dikog'ami) n. [Gk. 
dicha, in two ; gamos, union.] The 
maturing of the microsporophylls 
and the macrosporophylls at 
different times, thus ensuring cross- 
pollination (bot.}. 

dichoptic (dlkop'tlk) a. [Gk. dicha, 
in two ; opsis, sight.] With the 
eyes quite separate (zool.}. 

dichotomous (dlkflt'omus) a. [Gk. 
dicha, in two ; temnein, to cut.] 
Pert., situated near, or characterized 
by dichotomy (bot.}. 

dichotomy (dlkot'oml) n. [Gk. dicha, 
in two ; temnein, to cut.] Branching 
which results from the division of 
a growing point with two equal 
parts (bot., zool.}. 

dichromatic (dl'kromat'lk) a. [Gk. 
dt, two ; chroma, colour.] With 
two colour varieties (biol.}. 

diclinous (dfidinus, dlkli'nus) a. [Gk. 
di, two ; kline, bed.] With the 
stamens and pistils on separate 
flowers (bot.}. 

dicoccous (dlkok'us) a. [Gk. di, two ; 
kokkos, seed.] Having two one- 
seeded coherent capsules (bot.}. 

dicostalia (dl'kcteta'lla) n. [Gk. di, 
two ; L. costa, rib.] The secundi- 
branchs or second brachial series 
in a Crinoid (zool.}. 

dicotyledon (dlk5t!le'don) n. [Gk. 
di, two ; kotyledon, cup-shaped 
hollow.] A plant with two seed- 
leaves (bot.}. 

dictyodromous (dlk'tlSd'ro'mus) a. 
[Gk. diktyon, net ; dromein, to run.] 
Net-veined, when the smaller veins 
branch and anastomose freely (bot.}. 

dictyogen (dlk'tlqje'n) n. [Gk. diktyon, 




net ; gignesthai, to produce.] A 
net-leaved plant, appl. usually to 
monocotyledons (bot.). 

dictyonalia (dik'tiona'lia) n. [Gk. 
diktyon, net.] The principal par- 
enchyma spicules of the Dictyonina 
and of many Lyssacina (zool.). 

dictyostelic (dik'tioste'lik) a. [Gk. 
diktyon, net ; stele, stele.] Poly- 
stehc (bot.). 

dictyotic (dik'tiot'ik) a. [Gk. diktyon, 
net.] Having the whole skeleton 
laid down at once (zool.}. 

dictyotic moment, lorication mo- 
ment, which see. 

dicycllc (disik'lik) a. [Gk. di, two ; 
kyklos, circle.] Having a row of 
per-radial infrabasals, appl. theca 
of Crinoids (zool.) ; having two 
whorls (bot.). 

didactyl (didak'til) a. [Gk. di, two ; 
daktylos, finger.] Having two 
fingers or two toes (zool.~). 

didymous (did'imus) a. [Gk. didymos, 
twin.] Growing in pairs (bot., 

didynamous (didm'amus) a. [Gk. di, 
two ; dynamis, power.] With four 
stamens, two long, two short (bot.). 

diencephalon (di'enkgf'alon, -s6f'-) n. 
[Gk. dia, between ; engkephalon, 
brain.] See thalamencephalon 

differentiation (diferen'shta'shun) n. 
[L. differre, to differ.] The modifica- 
tion in structure of various organs 
of the body owing to a division of 
labour (zool.). 

diffluence (diflooens) n. [L. dis, 
away ; fluere, to flow.] Disintegra- 
tion by the formation of large 
vacuoles whose walls break on 
bursting (biol.). 

diffuse (difus') a. [L. diffundere, to 
pour.] Widely spread (biol.). 

digastric (digas'trik) a. [Gk. di, two ; 
gaster, belly.] Two-bellied, appl. 
muscles fleshy at the ends, tendinous 
in the middle (anat.). 

digenesis (dijeVesis) n. [Gk. dis, 
twice ; gignesthai, to produce.] 
Alternation of generations. 

digenetic (drjeneYik) a. [Gk. dis, 
twice ; gignesthai, to produce.] 
Pert, digenesis (biol.). 

digenoporous (dl'jgnop'orus) a. [Gk. 
dis, twice ; genos, birth ;poros, pore.] 

With two genital pores, said of 
many Turbellaria (zool.). 

digestion (dijeVchun) n. [L. digestio, 
digestion.] The process by which 
nutrient materials are rendered 
absorbable by the working of various 
juices and mechanical action (phys.). 

digestive (dijgs'tiv) a. [L. digestio, 
digestion.] Pert, digestion, or 
having the power of aiding in diges- 
tion (phys.). 

digit (dip) n. [L. digitus, finger.] 
A division of the limb in any 
vertebrate above Fishes (zool.). 

digital (dij'ital) a. [L. digitus, finger.] 
Pert, finger or digit, also appl. 
things resembling a digit (zool.). 

digital (dij'ital) n. [L. digitus, finger.] 
The distal joint of a spider's pedi- 
palp (zool.). 

digitaliform (dij'ital'iform) a. [L. 
digitus, finger ; forma, shape.] 
Finger-shaped, appl. corollae which 
are like the finger of a glove (bot.). 

digitate (dij'itat) a. [L. digitus, 
finger.] Having the parts arranged 
like the fingers in a hand (bot.) ; 
with fingers (zool.) ; finger-shaped 
(hot., zool.). 

digitiform (dlj'itiform) a. [L. digitus, 
finger ; forma, shape.] Finger- 
shaped ; appl. roots (bot.). 

digitigrade (dij'itTgrad) a. [L. digitus, 
finger ; gradus, step.] Having feet, 
the digits of which only touch the 
ground in walking (zool.). 

digitinervate (dij'itiner'vat) a. [L. 
digitus, finger ; nervus, a sinew.] 
Having the veins radiating out from 
the base like the fingers of a hand, 
with usually five or seven veins ; 
appl. leaves (bot.). 

digitipartite (dij'itipar'tit) a. [L. 
digitus, finger ; partire, to divide.] 
Having the leaves divided up in a 
hand-like pattern (bot.). 

digitipinnate (dij'itipin'at) a. [L. 
digitus, finger ;pinna, leaf.] Having 
digitate leaves of which the leaflets 
are pinnate (bot.). 

digitule (dlj'itul) n. [L. digitus, 
finger.] Any small finger-like pro- 
cess ; small process on the insect 
tarsi (zool.). 

digoneutic (dl'gonu'tik) a. [Gk. dis, 
twice ; goneuein, to produce.] 
Breeding twice a year (zool.). 




digonoporous (di'gonop'orus) a. [Gk. 
dis, twice ; genos, birth ; poros, 
pore.] With two distinct genital 
apertures, male and female (zool.}. 

difjynous (dij'inus) a. [Gk. di, two ; 
gyne, woman.] Having two carpels 

dihybrid (dlhl'brid) n. [Gk. dis, twice ; 
L. hibrida, mixed offspring.] A 
cross whose parents differ in two 
distinct characters (biol.}. 

dilatator (dii'ata'tor) n. [L. dilatare, 
to expand.] See dilator. 

dilated (dlla'tgd) a. [L. dilatare, to 
flatten.] Expanded or flattened ; 
appl. parts of insects, etc., with a 
wide margin (zoo/.). 

dilator (dlla'tor) n. [L. dilatare, to 
expand.] Name appl, any muscle 
that expands or dilates any organ 

dilophous (dllof'us) a. [Gk. di, two ; 
lophos, crest.] Any tetractinal 
spicule with two of its rays forked 
like a crest (zool.}. 

diluvial (dilu'vlal) a. [L. diluvium, 
deluge.] Pert, the present, in geo- 
logical reckoning (pal,}. 

dimerous (dim'erus) a. [Gk. dis, 
twice ; meros, part.] Having each 
whorl of two parts (hot.} ; with a 
two-jointed tarsus (zool.}, 

dimidiate (dimid'iat) a. [L. ditnidius, 
half.] Having only one-half de- 
veloped (biol.} ; having the capsule 
split on one side (dot.}. 

dimorphism (dlmor'fizm) n. [Gk. dis, 
twice ; morphe, shape.] Condition 
of having stamens of two different 
lengths, of having two different 
kinds of leaves, flowers, etc. (dot.}, 
State of having two different forms 
of one sex ; of having two different 
kinds of zooids ; of having two 
different kinds of offspring ; of 
having broods which, owing to 
differing conditions, differ in size or 
colouring (zool.}. 

dimyaric (dim'iar'ik) a. [Gk. dis, 
twice ; mys, muscle.] Having two 
adductor muscles (zool.}. 

dinomic (dlnom'lk) a. [Gk. dis, twice ; 
nomos, division.] Appl. an organism 
restricted to two of the biogeo- 
graphical divisions of the globe 

dioecious (dle'shus) a. [Gk. dis, 

twice ; oikos, house.] Having the 
sexes separate (zool.} ; having the 
male and female flowers on different 
individuals (bot.}. 

dioptrate (dlop'trat) a. [Gk. dis, 
twice ; root opt, to see.] Having 
the eyes or the ocelli separated by 
a narrow line (zool.}, 

dipetalous (dlpet'alus) a. [Gk. dis, 
twice ; petalon, petal.] Having 
two petals (bot.}. 

dlphycercal (dif'fser'kal) a. [Gk. 
diptyes, twofold ; kerkos, tail.] With 
a tail in which the vertebral column 
runs straight to the tip, thereby 
dividing the fin symmetrically 

dlphy genie (dlf'ijgn'lk) a, [Gk. di- 
phyes, twofold ; genos, birth.] With 
two types of development of the 
embryo (zool.}, 

diphyodont (dif'iodont') a. [Gk. 
diphyes, twofold ; odous, tooth.] 
With deciduous and permanent 
sets of teeth (zool.}. 

diplanetic (d^planSt'lk) a. [Gk. dis, 
twice ; planetikos, inclined to 
wander.] With two distinct types 
of zoospores (bot.}. 

diplarthrous (diplar'thrus) a. [Gk. 
diploos, double ; arthron, joint.] 
With the tarsal or carpal bones of 
one row articulating with two bones 
in the other (zool.}. 

dipleurula (diploor'ula) n. [Gk. dis, 
twice ; pleuron, side.] Any of the 
bilaterally symmetrical larvae of 
the Echinoderms ; an echino- 
paedium (zool.}. 

diploblastic (dlp'loblas'tik) a. [Gk. 
diploos, double ; blastos, bud.] 
Having two distinct germ layers 

diplocardiac (dlp'lokar'diak) a. [Gk. 
diploos, double ; kardia, heart.] 
With the two sides of the heart 
quite distinct (zool.}. 

diplocaulescent (dip'lokoles'e'nt) a. 
[Gk. diploos, double; kaulos, stem.] 
With secondary stems (bot.}. 

diploe (dip'loe) n. [Gk. diploos, 
double.] The cancellous tissue 
between the outer and inner 
lamellae of certain skull bones 

diplogangliate (dip'logang'gliat) a. 
[Gk. diploos, double ; gang-lion, 




ganglion.] With the ganglia 
usually arranged in pairs (zool.). 

diplogenesls (dip'lqjen'e'sis) n. [Gk. 
diploos, double ; genos, birth.] The 
supposed change in the germ plasm 
that accompanies the "use and 
disuse" changes occurring in the 
body tissues (biol.). 

diploic (diplo'ik) a. [Gk. diploos, 
double.] Occupying channels in 
the cancellous tissue of certain 
bones (anat.). 

diplonephridia (dip'lonefrid'ia) n. plu. 
[Gk. diploos, double ; nephros, 
kidney.] Nephridia derived partly 
from ectoderm, partly from meso- 
derm (zool.). 

diploneural (dip'ldnu'ral) a. [Gk. 
diploos, double ; neuron, nerve.] 
Supplied with two nerves (anat.). 

diploperistomous (dip'l6p6ris'tomus) 
a. [Gk. diploos, double ; peri, 
around ; stotna, mouth.] Having 
a double projection or peristome 

diploplacula (dip'ldplak'ula) n. [Gk. 
diploos, double; plakoeis, flat.] A 
flattened blastula consisting of two 
layers of cells (biol.}. 

diplopore (dip'lopor) n. [Gk. diploos, 
double ; poros, pore.] Respiratory 
organ in the Cystoidea (zool.). 

diplosoine (dip'losom) n. [Gk. diploos, 
double ; soma, body.] A double 
centrosome lying outside the 
nuclear membrane (cyt.). 

diplosphene (dip'ldsfen) n. [Gk. 
diploos, double ; sphen, wedge.] 
A wedge-shaped process on the 
neural arch of the vertebrae of 
certain fossil Reptiles (pal.). 

diplospondylic (dip'lospondil'ik) a. 
[Gk. diploos, double ; sphondylos, 
vertebra.] With two centra to 
each myotome, or with one centrum 
and a well-developed intercentrum 

diplostemonous (dip'lostem'dnus) a. 
[Gk. diploos, double ; stemon, warp.] 
With two whorls of stamens in 
regular alternation with the perianth 
leaves (dot.). 

diplotegia (dip'lote'jia) n. [Gk. 
diploos, double ; tegos, roof.] An 
inferior fruit with dry indehiscent 
pericarp (bot.). 

dipnoan (dip'noan) a. [Gk. dis, 

twice ; pnein, to breathe.] Breath- 
ing by gills and lungs (zool.). 

diprotodont (dipro'todont) a. [Gk. 
dis, twice ; protos, first ; oaous, 
tooth.] Having the two anterior 
incisors large and prominent, the 
rest of the incisors and canines 
being smaller or absent (zool.). 

dipterocecidlum (dip'terdsesid'umi) 
n. [Gk. dis, twice ; pteron, wing ; 
kekis, gall nut.] A gall caused by 
any insect (biol.). 

dipterous (dip'terus) a. [Gk. dis, 
twice ; pteron, wing.] With two 
wings or wing-like expansions (bot., 

directive body, a polar body (cyt.). 

directive mesenteries, in Zoan- 
tharia, the dorsal and ventral pairs 
of mesenteries (zool.). 

directive sphere, attraction sphere 

disc (disk) n. [Gk. diskos, disc.] 
Any flattened portion like a disc 
in shape (bot., zool.); the circumoral 
area in many animals ; the circular 
areas at the opposite poles of many 
animals (zool.) ; any modification 
of the thalamus (bot.) ; the area 
marking the entrance of the optic 
nerve into the eye ; cup-shaped 

- tactile structures in the skin ; the 
mass of cells of the membrana 
granulosa which projects into the 
cavity of the egg follicle (anat.). 

disc-florets, the inner florets borne 
on the abbreviated and reduced 
peduncle in many inflorescences 

discal (dis'kal) a. [Gk. diskos, disc.] 
Pert, any disc-like structure. 

discal (dis'kal) n. [Gk. diskos, disc.] 
A large cell at the base of the wing 
of lepidopterous insects completely 
enclosed by wing-nervures ; also 
in some Diptera (zool.). 

disciflorous (dis'kiflo'rus, dis'iflo'rus) 
a. [Gk. diskos, disc ; L. flos, 
flower.] With flowers in which 
the receptacle is large and disc- 
like (bot.). 

discoblastic (dis'kdblas'tik) a. [Gk. 
diskos, disc ; blastos, bud.] Pert. 
meroblastic eggs in which the area 
of segmentation is disc-shaped 

discoblastula (dls'kdblas'tula) n. [Gk. 




tiiskos, disc ; blastos, bud.] A 
blastula formed from a meroblastic 


with disc-like blastoderm 

discocarp (dis'kokarp) n. [Gk. diskos, 
disc ; karpos, fruit.] A special 
enlargement of the thalamus below 
the calyx (bot.). 

dlscoctasters (dis'koktas'terz) n. plu. 
[Gk. diskos, disc ; okto, eight ; 
aster, star.] Sponge spicules with 
eight rays terminating in discs, 
each disc corresponding in position 
to the corners of a cube ; a modi- 
fied hexactine (zoo/.). 

disced actylous (dis'kodak'tilus) a. 
[Gk. diskos, disc ; daktylos, finger.] 
With suckers at the ends of the 
fingers (zoo/.). 

discohexactine (dis'kohgksak'tin) n. 
[Gk. diskos, disc ; hex, six ; actis, 
ray.] A sponge spicule with six 
equal rays meeting at right angles 

discohexaster (dis'kdhgksas'ter) n. 
[Gk. diskos, disc ; hex, six ; aster, 
star.] A hexactine with the rays 
ending in discs (zoo/.). 

discoid (dis'koid) a. [Gk. diskos, 
disc ; eidos, resemblance.] Flat 
and circular ; disc-shaped. 

discoidal (dlskoi'dal) a. [Gk. diskos, 
disc ; eidos, like.] Disc-like ; appl. 
segmentation in which the blasto- 
derm forms a one-layered disc or cap 
which spreads over the yolk (emo.). 

discontinuous variation, see muta- 

disconula (diskon'ula) n. [Gk. diskos, 
disc.] An eight-rayed stage in the 
larval development of certain 
Coelenterates (zoo/.). 

discooctaster (dis'kooktas'ter), see 

discoplacenta (dis'koplasen'ta) ;;. [Gk. 
diskos, disc ; L. placenta, placenta.] 
A placenta with the villi on a 
circular cake-like disc (zoo/.). 

discus proligerus, in a Graafian 
follicle, the mass of cells immedi- 
ately surrounding the ovum (emb.). 

disjunct (disjungkt') a. [L. dis, apart ; 
jungere, to join.] Having the body 
regions separated by deep con- 
strictions (zoo/.). 

disjunctive symbiosis, a mutually 
helpful condition of symbiosis 

although there is no direct con- 
nection between the partners (oio/.). 

disk, see disc. 

dispermous (dispeYmus) a. [Gk. dis, 
twice ; sperma, seed.] Having two 
seeds (oof.). 

dispenny (dlspeYm!) n. [Gk. dis, 
twice ; sperma, seed.] The entrance 
of two spermatozoa into an ovum 

dispersal (dispeYsal) n. [L. dis, 
apart ; spargere, to strew.] The 
actual scattering or distributing of 
organisms on the earth's surface 


dispireme (dlspfrem) n. [Gk. dis, 
twice ; speirema, skein.] The stage 
of karyokinests in which each 
daughter nucleus has given rise to 
a spireme (cyt.). 

displacement (displas'mSnt) n. [O.F. 
desplacier, to displace.] An abnor- 
mal position of any part of a plant 
due to its shifting from its normal 
place of insertion (bot.\ 

dissected (disgk'ted) a. [L. dis, apart ; 
secure, to cut.] Having the lamina 
cut into lobes, the incisions reaching 
nearly to the midrib (eot.). 

dissepiment (disSp'iment) n. [L. dis, 
apart ; saepire, to hedge in.] The 
partition found in some compound 
ovaries (bot.) in Corals, one of 
the oblique calcareous partitions 
stretching from septum to septum 
and closing the interseptal loculi 
below (zoo/.). 

dissilient (dlsil'ien t) a. [L. dis, apart ; 
salire, to leap.] Springing open ; 
appl. capsules of various plants 
which dehisce explosively (bot.). 

dissoconch (dis'okongk') n. [Gk. 
dtssos, double ; kongche, shell.] The 
shell of a veliger larva (zoo/.). 

dissogeny (disoj'gni) n. [Gk. dissos, 
double ; genos, birth.] The con- 
dition of having two sexually mature 
periods in the same animal one in 
the larva, one in the adult (zoo/.). 

dissogony (disog'oni), see dissogeny. 

distal (dis'tal) a. [L. dis, apart ; stare, 
to stand.] Standing far apart, appl. 
bristles, etc. ; pert, end of any 
structure farthest from the middle 
line of the organism (oio/.). 

distichalia (dlstlka'lla) n. plu. [Gk. 
distichos, with two rows.] In 




Crinoids, the secondary brachalia, 
fixed or free (zool.). 

distichous (dis'tikus) a. [Gk. distiches, 
with two rows.] Pert, alternate 
leaves, so arranged that the first is 
directly below the third (bot.). 

distractile (distrak'til) a. [L. fit's, 
apart ; trahere, to draw.] Widely 
separate ; appl. usually to long- 
stalked anthers (dot.}. 

distribution (dis'tribu'shun) n. [L. 
dis, apart ; tribuere, to allot.] The 
range of an organism or group in 
the biogeographical divisions of the 
globe (Hoi.). 

dithecal (dithe'kal) a. [Gk. dis, twice ; 
theke, box.] Two-celled (bot.). 

ditokous (dit'okus) a. [Gk. dis, twice ; 
tokos, birth.] Producing two at a 
time, either eggs or young (zool.). 

ditrematous (dltre'matus) a. [Gk. 
dis, twice ; trema, opening.] With 
separate genital openings ; with 
anus and genital openings separate 

ditrochous (dlt'rokus) a. [Gk. dis, 
twice ; trochos, runner.] With a 
divided trochanter, or second joint 
of the limb (zool.). 

diurnal (dlur'nal) a. [L. dies, day.] 
Opening during the day only (bot.) ; 
active in the day-time (zool.). 

divaricate (divar'ikat) a. [L. dis, 
apart ; varicare, to straddle.] 
Widely divergent ; bifid ; forked 
(hot., zool.). 

divaricators (dl'varlka'torz) n. plu. 
[L. dis, apart ; varicare, to straddle.] 
Muscles stretching from the ventral 
valve to the cardinal process, and 
by their contraction opening the 
shell (zool.). 

divergency (diver'jenst) n. [L. dis, 
apart ; vergere, to bend.j The 
fraction of a stem circumference, 
usually constant for a species, which 
separates two consecutive leaves in 
a spiral (bot.). 

divergent (diver'jgnt) a. [L. dis, 
apart ; vergere, to bend.] Separ- 
ated from one another ; appl. leaves 

diverticulum (dl'vgrtlk'ulum) n. [L. 
de, away ; -vertere, to turn.] A tube 
or sac, blind at the distal end, 
branching off from a canal or cavity 

divided (divl'ded) a. [L. dividere, to 
divide.] With the lamina cut by 
incisions which reach the midrib ; 
appl. leaves (bot.). 

division (divlzh'un) n. [L. dividere, 
to divide.] One of the smaller 
groups of organisms which together 
form a larger group (biol.) ; one of 
the separate parts of which any 
structure may be composed (biol.). 

dizoic (dlzo'ik) a. [Gk. dis, twice; 
zoon, animal.] Pert, spore con- 
taining two sporozoites (zool.). 

dodecagynous (do'dekaj'inus) a. [Gk. 
dodeka, twelve ; gyne, woman.] 
Having twelve pistils (bot.). 

dodecamerous (do'dekam'erus) a. 
[Gk. dodeka, twelve ; meros, part.] 
Having each whorl composed of 
twelve parts (bot.). 

dodecandrous (do'dekan'drus) a. 
[Gk. dodeka, twelve ; aner, man.] 
Having at least twelve stamens 

dolabriform (dolab'riform) a. [L. 
dolabra, mattock ; forma, shape.] 
Axe-shaped (biol.). 

dolichostylous (dol'lkostl'lus) a. [Gk. 
dolichos, long ; stylos, pillar.] Pert. 
long-styled anthers in dimorphic 
flowers (bot.). 

dolioform (do'lioform) a. [L. dolium, 
jar ; forma, shape.] Shaped like 
a barrel (zool.). 

dominant characters, see Men- 

dormant (dor'mant) a. [L. dormire, 
to sleep.] Resting ; appl. any 
structure or feature which may 
develop later (Hoi.). 

dorsal (dor'sal) a. [L. dorsum, back.] 
Pert, or lying near the back as 
opp. the venlral surface (anat.) ; 
pert, surface farthest from the 
axis ; the upper surface of the 
thallus or prothallus of ferns, etc. 

dorsalis (dorsa'lis) n. [L. dorsum, 
back.] The artery which supplies 
the back of any organ (anat.). 

dorsiferous (dorsif'erus) a. [L. 
dorsum, back ; ferre, to carry.] 
With the sori on the back of the 
leaf (bot.) ; carrying the young on 
the back (zool.). 

dorsifixed (dor'sifik'st) a. [L. dorsum, 
back ; fingere^ to fix.] Having the 




filament attached to the back of the 

anther, which is immovable (dot.). 
dorsigrade (dor'sigrad) a. [L. 

dorsum, back ; gradus, step.] 

Having the back of the digit on 

the ground when walking (zool.). 
dorsispinal (dor'slspl'nal) a. [L. 

dorsum, back ; spina, spine.] Pert. 

or referring to the back and spine 

dorsiventral (dor'siven'tral) a. [L. 

dorsum, back ; venter, belly.] With 

upper and lower surfaces distinct 

dorsocentral (dor'sosen'tral) a. [L. 

dorsum, back ; centrum, centre.] 

Pert, mid-dorsal surface ; pert. 

aboral surface of Echinoderms 

dorsolumbar (dor'solum'bar) a. [L. 

dorsum, back ; lumbus, loin.] Pert. 

lumbar region of the back (zool.). 
dorsoumbonal (dor'soumbo'nal) a. 

[L. dorsum, back ; umbo, umbo.] 

Lying on the back near the umbo 

dorsoventral (dor'soven'tral) a. [L. 

dorsum, back ; venter, belly.] Pert. 

structures which stretch from the 

dorsal to the ventral surface (zool.). 
dorsulum (dor'sulum) n. [L. d 

back.] The upper surface lying 
between the collar and scutellum ; 
the mesonotum (zool.). 

dorsum (dor'stim) n. [L. dorsum, 
back.] The sulcular surface of 
Anthozoa ; the tergum or notum 
of Insects and Crustacea ; the back 
or higher animals (zool.). 

drepanium (drSpa'nlum) n. [Gk. 
drepanon, sickle.] A helicoid cyme 
with the secondary axes developed 
in a plane parallel to that of the 
main peduncle and its first branch 

dromaeognathous (dro'meog'nathus) 
a. [Gk. dromein, to run ; gnathos, 
jaw.] Having a palate in which 
the palatines and pterygoids do 
not articulate, owing to the inter- 
vention of the vomer (zool.). . 

dromotropic (dro'motrop'lk) a. [Gk. 
dromos, course ; trepein, to turn.] 
Bent in a spiral (bot.). 

drone (dron) n. [A.S. dran.} The 
male of any species of bee (zool.). 

drupaceous (droopa'shus) a. [Gk. 

druppa, berry.] Pert, drupe ; 
bearing drupes ; drupe-like (bot.). 

drupe (droop), n. [Gk. druppa, 
berry.] A superior, one-celled 
fruit with one or two seeds and 
a fleshy sarcocarp, a hard endocarp 
and the pericarp separable into its 
component parts (bot.). 

drupels (droop'6lz) n. plu. [Gk. 
druppa, berry.] The individual 
components of the fruit of the 
raspberry (bot.). 

duct (diikt) n. [L. ducere, to lead] ; 
also ductus. Any tube which 
conveys fluid or other substance 
(anat.) ; a tube formed by a series 
of cells which have lost their walls 
at the points of contact (bot.). 

ductless glands, glands which do 
not communicate with any organ 
directly by means of a duct, e.g. 
spleen (anat.). 

ductule (dtik'tul) n. [L. ducere, to 
lead.] The fine thread-like 
terminal portion of a duct (anat.). 

ductus (duk'tus) n. [L. ducere, to 
lead.] See duct. 

ductus ejaculatorius, the common 
duct into which the vasa deferentia 
open in Insects; a narrow muscular 
tube at the end of the vas deferens 
in various invertebrates (zool.). 

duodenal (du'ode'nal) a. [L. duodeni, 
twelve each.] Pert, duodenum 

duodenum (du'dde'num) n. [L. 
duodeni, twelve each.] That por- 
tion of the small intestine next to 
the pyloric end of the stomach 

duplication (du'pllka'shun) n. [L. 
duplex, double.] See chorisis. 

duplicature (du'plika'tur) n. [L. 
duplex, double.] A circular fold 
near the base of the protrusible 
portion of a polyzoan polypide 

duplicident (duplis'Idgnt) a. [L. 
duplex, double ; dens, tooth.] 
Having two pairs of incisors in 
the upper jaw, one behind the 
other (zool.). 

duplicodentate (du'plikoden'tat) a. 
[L. duplex, double ; dens, tooth.] 
With the marginal teeth on the 
leaf bearing smaller teeth-like 
structures (bot.). 





dura mater (du'ra ma'ter, door'a 
mat'eY) n. [L. dura, hard ; mater, 
mother.] The tough membrane 
lining the whole cerebro-spinal 
cavity (anat.}. 

dura spinalis, the tough membrane 
lining the spinal canal (anat.}. 

duramen (dura'me'n) n. [L. durare, 
to harden.] The hard, darker 
central region of a tree-stem ; the 
heart wood (hot.). 

dwarf male, the small three- or four- 
celled plant formed from the andro- 
spore of Oedogonium (hot.} ; a small, 
usually simply formed, individual in 
many classes of animals, either free 
or carried by the female (zool.). 

dyad (dl'ad) n. [Gk. dyas, two.] The 
half of a tetrad group (cyt.). 

dyaster (dl'aster) n. [Gk. dyas, two ; 
aster, star.] " The double group of 
chromosomes during the anaphases 
of cell-division " (cyt.). 

dyne (din) n. [Gk. dynamis, power.] 
The unit of force in the C.G. system 
of physical units (phys.). 

dysmerism (dTs'merizm) . [Gk. dys, 
hard ; meros, part.] An aggregate 
of unlike parts (biol.). 

dysmerogenesis (dls'merqjen'esis) n. 
[Gk. dys, hard ; meros, part ; genesis, 
birth.] Segmentation resulting in 
unlike parts (biol.). 

dysoxidize (disok'sidiz) v. [Gk. dys, 
hard ; oxys, sharp.] To find difficult 
to oxidize (phys.). 

dyspnoea (dis pnea) n. [Gk. dys, 
hard ;pnein, to breathe.] Difficulty 
in breathing (phys.). 

dysteleology (dis'te'le'ol'oji) n. [Gk. 
dys, hard ; telos, end ; logos, dis- 
course.] Haeckel's doctrine of 
purposelessness in nature (biol.). 

dzlerzon (dzer'tson) theory, the belief 
that the males of the honey-bee are 
always produced from unfertilized 
eggs (zool.}. 

ear (er) n. [A.S. eare.] The auditory 
organ (anat.) ; the various structures 
among invertebrates supposed to 
have an auditory function ; the 
specialized tufts of hair or feathers 

which are close to, or similar to an 
external ear or pinna (zool.) ; an 
ear-shaped structure ; the spike of 
any cereal (bot.). 

eared (erd) n. [A.S. eare.} Having 
external ears or pinnae ; with tufts 
of feathers resembling ears (zool.) ; 
having long bristles or processes, as 
in the grains of corn, etc. (bot.). 

ebracteate (ebrak'teat), ebracteolate 
(ebrak'teolat) a. [L. ex, from ; 
bracteatus, covered with a gold 
plate.] Without bracts, or without 
bracteoles, reduced leaves on the 
flower-stalk (bot.). 

ecalcarate (ekal'karat) a. [L. ex, 
without ; calcar, spur.] Having no 
spur (zool.) ; with no spur-like pro- 
cess on the petals (bot.). 

ecardinal (ekar'dinal) a. [L. ex, 
without ; cardo, hinge.] Having 
no hinge ; also ecardinate (zool.). 

ecarinate (ekar'inat) a. [L. ex, with- 
out ; carina, keel.] Not furnished 
with a keel or keel-like ridge (bot., 

ecaudate (eko'dat) a. [L. ex, without ; 
cauda, tail.] Without a tail (zool.). 

ecblastesis (ek'blaste'sis) n. [Gk. ek, 
out of; blastos, bud.] A prolifera- 
tion of the main axis of an inflores- 
cence (bot.). 

ecdemic (ekdem'ik) a. [Gk. ek, out 
of ; demos, people.] Not native. 

ecderon (ek'deron) n. [Gk. ek, out ; 
deros, skin.] The outer or epi- 
dermal layer of the skin (anat.). 

ecderonic (ek'deronlk) a. [Gk. ek, 
out ; deros, skin.] Ectodermic ; 
epiblastic (smb.). 

ecdysis (ekdl'sis) n. [Gk. ek, out; 
dyein, to enter.] The act of moult- 
ing any particular cuticular layer or 
structure (zool.). 

echinate (eVinat) a. [Gk. echinos, 
spine.] Furnished with spines or 
bristles (zool.). 

echinochrome (gk'inokrom', ekl'no- 
krom) n. [Gk. echinos, spine ; 
chroma, colour.] A colouring pig- 
ment found in Echinoderms (zool.). 

echinoid (eVinoid, gkfnoid) a. [Gk. 
echinos. spine.] Pert, sea-urchins 

echinopaedium (ek'fnope'dfum, ekl'no- 
pe'dium) n. [Gk. echinos, spine ; 
pais, child.] See dipleurula. 




echinopluteus (eVinoploo'teus, e'kl'no- 
ploo'teus) n. [Gk. echinos, spine ; 
L. pluteus, shed.] The larva or 
pluteus of echinoids, from its sup- 
posed resemblance to an upturned 
easel (zool.). 

echinulate (6kin'ulat) a. [Gk. echinos, 
spine.] Having small spines (zool.). 

ecology (ekol'qji) n. [Gk. oikos, house ; 
logos, discourse.] That part of 
biology which deals with the re- 
lationship between organisms and 
their surroundings (biol.). 

ectental (gktgn'tal) line, the line 
where the ectoderm and endoderm 
meet at the blastopore of a gastrula 

ectethmoid (ekteth'moid) n. [Gk. 
ektos, without ; ethmos, sieve ; eidos, 
resemblance.] The lateral ethmoid 
bone (anat.). 

ecthoraeum (ek'thore'um) n. [Gk. 
ekthroskein, to leap out.] The 
thread of a nematocyst (zool.}. 

ectoblast (ek'toblast) n. [Gk. ektos, 
without ; blastos, bud.] See epi- 

ectobronchium (ek'tobrong'kium) n. 
[Gk. ektos, without ; brongchos, wind- 
pipe.] See ectobronchus. 

ectobronchus (ek'tobrong'kus) n. [Gk. 
ektos, without ; brongchos, wind- 
pipe.] A lateral branch of the 
main bronchus in birds (zool.). 

ectocarpous (ek'tokar'pus) a. [Gk. 
ektos, without; karpos, fruit.] Having 
the gonads of ectodermal origin 

ectochondrostosis (ek'tdkondrosto'sis) 
n. [Gk. ektos, without ; chondros, 
cartilage ; osteon, bone.] The de- 
position of lime-salts beginning in 
the perichondrium and gradually 
invading the cartilage (anat.). 

ectochone (ek'tokon) n. [Gk. ektio, 
without ; choane, funnel.] A funnel- 
shaped chamber into which the 
ostia in certain Sponges lead (sool.). 

ectocoelic (eYtose'lik) a. [Gk. ektos, 
outside ; koilos, hollow.] Pert. 
structures situated outside the 
enteron of the Coelenterates (zool.). 

ectocondyle (elc'tdkon'dil) n. {Gk. 
ektos, outside ; kondylos, knob.] 
The outer condyle of a bone 

ectocranial (eYtokra'nial) a. [Gk. 

ektos, outside ; kranton, skull.] 
Pert, outside of skull (anat.). 

ectocuneiform (gk'tokune'iform) n. 
[Gk. ektos, outside ; L. cuneus, 
wedge ; forma, shape.] A bone in 
the distal row of the tarsus (anat.). 

ectocyst (ek'toslst) n. [Gk. ektos, 
outside ; kystis, bladder.] The 
outer layer of the zoecial wall in 
Polyzoa (zool.). 

ectoderm (eYtddgrm) n. [Gk. ektos, 
outside ; derma, skin.] The outer 
layer of a multicellular animal, 
when composed of cells (zool.) ; 
the epidermis in higher mammals 

ectogenous (ektoj'e'nus) a. [Gk. ektos, 
outside ; gignesthai, to produce.] 
Able to live an independent life ; 
appl. Bacteria (dot.). 

ectoglla (ektog'lia) n. [Gk. ektos, 
outside ; glia, glue.] An outer 
layer of cells in the central 
nervous system (anat.). 

ectolecithal (6k'tol6s'ithal) a. [Gk. 
ektos, outside ; lekithos, yolk of an 
egg.] Having the yolk surround- 
ing the formative protoplasm 

ectoloph (gk'tolof) n. [Gk. ektos, 
outside ; lophos, crest.] The ridge 
stretching from the paracone to 
the metacone in a lophodont molar 

ectomere (ek'tomer) n. [Gk. ektos, 
outside ; meros, part.] An epiblast 
cell which gives rise to ectoderm 

ectoparasite (eYtopar'asit) n. [Gk. 
ektos, outside ; para, beside ; sttos, 
food.] A parasite that lives on 
the exterior of an organism (zool.). 

ectopatagium (ek'topata'jium) . 
[Gk. ektos, outside ; L. patagium, 
border.] The part of the wing- 
like membrane of bats carried on 
the metacarpals and the phalanges 

ectophyte (eVtoflt) n. [Gk. ektos, 
outside ; phyton, plant.] Name 
given to an external parasite in 
the plant world (bot.). 

ectoplasm (Sk'to'plazm) n. [Gk. 
ektos, outside ; plasma, something 
moulded.] The external layer of 
protoplasm in a cell, usually slightly 
modified (diol.) ; the ectosarc in a 




protozoan cell (zool.) ; the layer 
next the cell-wall (bot.). 

ectosarc (ek'tosark) n. [Gk. ektos, 
outside ; sarx, flesh.] The ex- 
ternal, often highly specialized, 
layer of protoplasm in a Proto- 
zoon (zool.). 

ectosome (ek'tosom) n. [Gk. ektos, 
outside ; soma, body.] The en- 
veloping portion of a Sponge con- 
taining no flagellated chambers 

ectosphere (ek'tosfer) n. [Gk. ektos, 
outside ; sphaira, globe.] The 
outer zone of the attraction sphere 

ectosppre (ek'tospor) n. [Gk. ektos, 
outside ; sporos, seed.] The spore 
formed at the end of each sterigma 
in the Basidiomycetes (bot.). 

ectostosis (ek'tosto'sis) n. [Gk. ektos, 
outside ; osteon, bone.] Formation 
of bone in which the ossification 
begins under the perichondrium 
and either surrounds or replaces 
the cartilage (anat.). 

ectotheca (ek'tothe'ka) . [Gk. ektos, 
outside ; theke, cup.] The outer 
coating of the gonotheca in certain 
Hydroids (zool.). 

ectotrophic (ek'totro'f Ik) a. [Gk. ektos, 
outside ; trephein, to nourish.] Find- 
ing nourishment from outside ; appl. 
Fungi which surround the roots of 
the host with a web of hyphae (bot.). 

ectoturbinal (ek'totur'bmal) n. [Gk. 
ektos, outside ; L. turbo, whirl.] 
One of the divisions of the ethmo- 
turbinals (zool.). 

ectozopn (ek'tozo'on) n. [Gk. ektos, 
outside ; zoon, animal.] An ex- 
ternal parasite (zool.). 

edaphic (edaf'ik) a. [Gk. edaphos, 
soil.] Pert, or influenced by the 
conditions of the soil (phys.). 

edentate (eden'tat) a. [L. ex, with- 
out ; dens, tooth.] Without teeth 
(zool.) ; without tooth-like projec- 
tions (bot.). 

edriophthalmlc (gd'Hofthal'mik) a. 
[Gk. edra, seat ; ophthalmos, eye.] 
Having sessile eyes ; appl. certain 
Crustacea (zool.). 

efferent (ef'firent) a. [L. ex, out ; 
ferre, to carry.] Conveying from, 
appl. vessels, lymphatics, etc. 
(anat.) ; carrying outwards, appl. 

impulses carried outwards by the 
motor nerves (phys.). 

egest (ejest') v. [L. ex, out ; gerere, 
to carry.] To throw out ; to void ; 
to excrete (phys.). 

egg (eg) n. [Icel.^gg-.] The matured 
germ-cell of a female plant or animal 

egg-albumin, the chief constituent 
of the white of egg, known to be a 
mixture of glucoproteids (phys.). 

egg-apparatus, the two synergids 
and ovum proper, near the micro- 
pyle in the embryo sac of seed 
plants (bot.). 

egg-case, a protective covering 
formed by many animals for their 
eggs (zool.). 

egg-cell, the ovum proper apart 
from any layer of cells derived 
from it or from other cells (zool.). 

egg-membrane, the layer of tough 
tissue lining the shell of an egg 

egg-nucleus, the female pronucleus 

egg-tooth, a small horny and cal- 
careous structure on the tip of the 
beak by means of which the embryo 
breaks the shell (zool.). 

ejaculation (ejak'ula'shun) n. [L. ex, 
out ; jacere, to throw.] Act of 
suddenly ejecting a fluid from a 
duct (phys?). 

ejaculatory (ejak'ulatori) a. [L. ex, 
out ; jacere, to throw.] Throwing 
out, appl. function of certain ducts 

elaborate (elab'orat) v. [L. ex, out ; 
laborare, to work.] To change 
from a crude state to a state cap- 
able of assimilation (pkys.) ; to 
form complex organic substances 
from simple materials (bot.). 

elaeoblast (ele'oblast) n. [Gk. elaion, 
oil ; blastos, bud.] A mass of 
nutrient material at the posterior 
end of the body in certain Tunicates 

elaeodochon (el'eod'okon) n. [Gk. 
elaiodochos, oil-containing.] The 
preen-gland or oil-gland in birds 

elaioplast (ell'oplast') n. [Gk. elaion, 
oil ; plastos, moulded.] A plastid 
in a plant cell which forms or helps 
to form oil globules (bot.). 



EM In- 

elastic fibres, special fibres, often 
branched and highly resistant to 
the action of boiling water, but 
easily acted on by tryptic digestion 

elastic fibro-cartilage, consists of 
cartilage cells and a matrix per- 
vaded by a network of yellow 
elastic fibres which branch and 
anastomose in all directions (anat.). 

elastic tissue, a type of connective 
tissue in which elastic and yellowish 
fibres are mixed with the non- 
elastic fibres (phys.). 

elastin (elas'tin) n. [Gk. elauein, to 
drive.] The substance which forms 
elastic tissues (phys.). 

elater (el'ater) n. [Gk. elater, driver.] 
One of the cells in certain plants 
with a spiral thickening in the 
wall which assists in dispersing 
the spores (bot.). 

electric organ, modifications of 
muscles or groups of muscles 
which discharge a considerable 
amount of electric energy, found 
in certain Fishes (zool.). 

electroplax (616k'troplaks) n. [Gk. 
elektron, amber ; plax, anything 
broad and flat.] One of the con- 
stituent plates of an electric organ, 
which are arranged at right angles 
to the axis of the primitive muscle 

electro-tonic (gleYtroton'ik) a. [Gk. 
elektron, amber ; tonos, tension.] 
Pert, a state ofelectric tension (phys.). 

electrotonus (elfiktrot'onus) n. [Gk. 
elektron, amber ; tonos, tension.] 
The modified condition of a nerve 
when subjected to a constant 
current of electricity (phys.). 

eleidin (ele'Idln) n. [Gk. eleos, 
wandering.] A substance found 
as small granules in the stratum 
granulosum of the epidermis, 
probably a stage in the formation 
of keratin (phys.). 

element (eTement) n, [L. elementum, 
unit.] A substance that cannot 
be separated into simpler substances 

eleutherodactyl (61u'th6rodak'tTl) a. 
[Gk. eleutheros, free ; daktylos, 
finger.] Having the hind toe 
free (zool.). 

eleutheropetalous (glu'thgropeValiis) 

a. [Gk. eleutheros, free ; petalon, 
petal.] Having the petals or the 
components of the whorl free or 
separate (dot.). 

eleutherophyllous (61u'th6r6fil'us) a. 
[Gk. eleutheros, free ; phyllon, leaf.] 
Having the components of the 
perianth whorls free (bot.). 

eleutherosepalous (61u'th6rosep'alus) 
a. [Gk. eleutheros, free ; sepalon, 
sepal.] Having the sepals free and 
separate (dot.). 

elliptical (glip'tikal) a. [Gk. elleipsis, 
a falling short.] Oval-shaped ; 
appl. leaves of about the same 
breadth at equal distances from 
base and apex, which are slightly 
acute (hot.). 

elytriform (elit'riform) a. [Gk. elytron, 
sheath ; L./orma, shape.] Shaped 
like an elytrum (zool.). 

elytroid (elit'roid) a. [Gk. elytron, 
sheath ; eidos, resemblance.] Re- 
sembling an elytrum (zool.). 

elytrum (elit'riim) n. [Gk. elytron, 
sheath.] The anterior wing of 
certain insects, hard and case-like ; 
one of the scales or shield-like 
plates found on the dorsal surface 
of some worms (zool.). 

emarginate (emar'jinat) a. [L. ex, 
put ; marginare, to delimit.] Hav- 
ing a triangular notch at the apex 
(bot.) ; having the tip notched (zool.). 

embole (em'bole) n. [Gk. embole, 
putting into place.] Invagination 

embolic (embol'lk) a. [Gk. embolos, 
anything pointed.] Pushing or 
growing in (emb.). 

embolium (gmbo'lium) n. [Gk. 
embolos, pointed.] The outer or 
costal part of the wing in certain 
insects (zool.). 

embolomerous (e'm'bolom'e'rus) a. 
[Gk. embolos, anything pointed ; 
meros, part.] Having two verte- 
bral rings in each segment due 
to the union of the hypocentra 
with the neural arch, and the 
union of the two pleurocentra 
below the notochord (anat.), 

embryo (gm'brio) n. [Gk. embryon, 
embryo.] Any young organism 
in the early stages of its develop- 
ment before it has become self- 
supporting (biol.). 




embryo cell, one of the two cells 
formed from the first division of 
the fertilized egg in certain plants, 
developing later into the embryo, 
the other developing into the 
suspensor (bot.). 

embryo sac, the megaspore (bot.). 

embryogeny (embrioj'en!) n. [Gk. 
embryon, embryo ; genos, birth.] 
The processes by which the embryo 
is formed (emb.). 

embryology (embriol'dji) n. [Gk. 
embryon, embryo ; logos, discourse.] 
That part of biology dealing with 
the formation and development of 
the embryo (biol.). 

embryonic (embrion'ik) a. [Gk. em- 
bryon, embryo.] Pert, embryo (biol.). 

embryophore (em'briofor) n. [Gk. 
embryon, embryo ; pherein, to bear.] 
The ciliated mantle enclosing the 
embryo in many tape-worms, and 
formed from the superficial 
blastomeres of the embryo (zool.). 

embryotegia (Smbriote'jia) n. [Gk. 
embryon, embryo ; tegos, roof.] The 
small hardened portion of the testa 
which marks the micropyle in some 
seeds and separates like a little lid 
at the period of germination (bot.). 

embryotrophy (Sm'briot'rofi) n. [Gk. 
embryon, embryo ; trephein, to 
nourish.] The nourishment of the 
embryo, or the means adapted to 
that purpose (emb.). 

emergence (emeYjens) n. [L. ex, out ; 
mergere, to dip.] Any of the out- 
growths which arise from the sub- 
epidermal tissue (bot.) zool.). 

emersed (emers't) a. [L. ex, out ; 
mergere, to dip.] Rising above the 
surface of the water ; appl. leaves 

eminence (em'inens) n. [L. eminens, 
eminent.] Ridge or projection on 
the surface of bones (anat.). 

emlnentla (em'ine'n'shla) n. plu. [L. 
eminens, eminent.] Eminences. 

emissary (em'isari) a. [L. emittere, 
to send out.] Coming out ; name 
appl. veins passing through aper- 
tures in the cranial wall and estab- 
lishing connection between the 
sinuses inside and the veins outside 

empodium (gmpo'dium) n. [Gk. en, 
in ; pous, foot.] A small variable 

median structure between the claws 
of many insects' feet (zool.). 

emulsln (emiil'sin) n. [L. emulgere, 
to milk out.] An enzyme found in 
certain plants (bot.). 

enamel (enam'el) n. [O.F. esmaillier, 
to coat with enamel.] The hard 
material containing over 90 per 
cent, calcium and magnesium salts 
which forms a cap over the dentine, 
or may form a complete coat to the 
tooth or scale in which it is found 

enamel cells, the cells which form 
the enamel and are collectively 
known as the enamel organ. 

enantioblastic (enan'tloblas'tik) a. 
[Gk. enantios, opposite ; blastos, 
bud.] Formed at the end of the 
seed opposite the placenta (bot.). 

enarthrosis (en'arthro'sis) n. [Gk. en, 
in ; arthron, joint.] Ball-and-socket 
joint (anat.). 

encephalocoel (enkef'alosel, -sef-) n. 
[Gk. enkephalos, within the head ; 
koilos, hollow.] The cavity within 
the brain (zool.). 

encephalon (enkef'alon, -sef-) n. [Gk. 
enkephalos, within the head.] The 
brain (anat.). 

encephalospinal (enkef'alospi'nal, 
-sSf-) a. [Gk. enkephalos, within 
the head ; L. spina, spine.] Pert. 
the brain and spinal cord (anat.). 

enchylema (en'klle'ma) n. [Gk. en, 
in ; chylos, juice.] The more fluid 
protoplasm in a cell (biol.) : 

encyst (ensist') v. [Gk. en, in ; kystis, 
bladder.] Of a cell or small animal, 
to surround itself with an outer coat 
or capsule (biol.). 

encystation (ensista'shun) n. [Gk. 
en, in ; kystis, bladder.] Forma- 
tion of a cyst or capsule (biol.). 

encystment (ensist'ment) n. [Gk. 
en, in ; kystis, bladder.] Formation 
of a firm, resistant envelope or 
capsule (biol.). 

endarch (find'ark) a. [Gk. endon, 
within ; arche, beginning.] With 
a central protoxylem, or with 
several surrounding a central pith 

endaspidean (end'aspid'ean) a. [Gk. 
endon, within ; aspis, shield.] With 
the scutes extending on the inner 
surface of the tarsus (zool.). 



end-bulbs, minute cylindrical or oval 
bodies, consisting of a capsule 
containing a semi-fluid core in 
which the axis cylinder terminates 
either in a bulbous extremity or in 
a coiled plexiform mass (anat.). 

endemic (SndSm'lk) a. [Gk. en, in ; 
demos, the people.] Restricted to a 
certain region or part of a region 

enderon (Sn'dSron) n. [Gk. en, in ; 
deros, skin.] The inner or endo- 
dermal layer (ana/.). 

enderonic (Sn'de'ron'ik) a. [Gk. en, 
in ; deros, skin.] Endodermal. 

endites (gndlts') n. plu. [Gk. endon, 
within.] The offshoots on the 
mesial border of the appendages 
of certain Crustacea (zool.). 

endoblast (gn'doblast) n. [Gk. endon, 
within ; blastos, bud.] The hypo- 
blast (emd.). 

endocardiac (gn'dokar'diak) a. [Gk. 
endon, within ; kardia, heart.] Situ- 
ated within the heart (anat). 

endocardlal (gn'dokir'dial), see 

endocardium (gn'ddkar'dium) n. [Gk. 
endon, within ; kardia, heart.] The 
thin smooth membrane which lines 
and gives the glistening appearance 
to the inner surface of the heart 

endocarp (fin'dokarp) n. [Gk. endon, 
within ; karpos, fruit.] The inner- 
most layer of the pericarp, usually 
hard and stony, in drupaceous fruits 

endocarpold (Sn'dokar'poid) a. [Gk. 
endon, within ; karpos, fruit.] Having 
the disc-like ascocarps embedded in 
the thallus (dot.). 

endochondral (6n'd6kon'dral) a. [Gk. 
endon, within ; chondros, cartilage.] 
Beginning or forming inside the car- 
tilage, usually appl. ossification 

endochone (gn'dokon) . [Gk. endon, 
within ; choane, funnel.] Spacious 
sub-cortical crypt in the tissue of 
Sponges from which the incurrent 
canals start (zool.). 

endochrome (gn'dokrom) plate, a 
band of yellowish chromatophores 
found in the protoplasmic portion 
of certain Diatoms (dot.). 

endochylous (eVdokl'lus) a. [Gk. 

endon, within ; chylos, juice.] With 
the water-cells within the internal 
tissue (dot.). 

endocoelar (n'dose'lar) a. [Gk. endon, 
within ; koilos, hollow.] Pert, the 
inner wall of the coelom, i.e. the 
splanchnic wall (zool.). 

endpcone (Sn'docon) n. [Gk. endon, 
within ; konos, cone.] One of the 
conical structures formed in certain 
cephalopod shells (Pal.). 

endocranium (gn'dokra'nium) n. [Gk. 
endon, within ; kranion, skull.] The 
process on the inner surface of the 
cranium of certain insects (zool.). 

endocrine (Sn'dokrfn) a. [Gk. endon, 
within ; krinetn, to separate.] Appl. 
organs of internal secretion (phys.). 

endocyde (gn'dosl'kl) n. [Gk. endon, 
within ; kyklos, circle.] A layer of 
tissue separating the internal phloem 
from the endodermis (dot.). 

endocycllc (gn'dosik'lik) a. [Gk. 
endon, within ; kyklos, circle.] With 
the mouth remaining in the axis of 
the coil of the gut, appl. Crinoids ; 
having an apical system with a 
double circle of plates surrounding 
the anus, appl. Echinoids (zool.) ; 
pert, endocycle (dot.). 

endocyst (gn'dosist) n. [Gk. endon, 
within ; kystis, bladder.] The soft 
body wall of a zooid in a Polyzoan 

endoderm (gn'dodgrm) n. [Gk. endon, 
within ; derma, skin.] The hypo- 
blast ; the epithelium of the digestive 
and respiratory organs, and of the 
glands appended to the digestive 
tract (emd.). 

endoderm disc, the posterior un- 
paired thickening on the ventral 
surface of the blastoderm of the 
crayfish (zool.). 

endoderm lamella, a thin sheet of 
endoderm stretching between ad- 
jacent radial canals, and between 
the circular canal and the enteric 
cavity in certain Coelenterates 

endodermis (en'dodeVmis) n. [Gk. 
endon, within ; derma, skin.] The 
innermost layer of the cortex in 
plants (dot.). 

endogamy (findSg'ami) n. [Gk.end0n, 
within ; gamos, marriage.] Zygote 
formation within the cyst by the 



reciprocal fusion of the division 
products of the daughter nuclei 

endogastric (6n'dogas'trik) a. [Gk. 
endon, within ; gaster, belly.] Hav- 
ing the curvature of the body with 
the enclosing shell towards the 
ventral side (zool.}. 

endogenous (gndoj'enus) a. [Gk. 
endon, within ; genos, birth.] De- 
veloping from a deep-seated layer 

endogenous multiplication, see 

spore formation. 

endogeny (findqj'Sni) n. [Gk. endon, 
within ; genos, birth.] Development 
from a deep-seated layer (biol.). 
endognath (en'dognath') n. [Gk. 
endon, within ; gnathos, jaw.] The 
inner branch of the oral appendages 
of Crustacea (zool.). 
endognathion (gn'dognath'ion) n. 
[Gk. endon, within ; gnathos, jaw.] 
The mesial segment of the maxilla 
in man, bearing a central incisor 

endogonidium (Sn'dogonid'ium) . 
[Gk. endon, within ; gonos, offspring.] 
A gonidium formed in a receptacle ; 
the colony-forming cells in such 
forms as Volvox (bot.). 
endolabium (Sn'dola'blum) n. [Gk. 
endon, within ; L. labium, lip.J A 
membranous lobe in the interior of 
the mouth on the middle parts of 
the front of the labium (zool.). 
endolaryngeal (en'dolar'mje'al, -larin'- 
jeal) a. [Gk. endon, within ; laryngx, 
larynx.] Pert, inside of, or situated 
in, the larynx (anat.). 
endolymph (en'dolimf) n. [Gk. endon, 
within ; L. lympha, water.] The 
fluid in the inner labyrinth of the 
ear (anat.). 

endolymphangial (gn'dolimf an'jlal) a. 
[Gk. endon, within ; L. lympha, 
water ; Gk. anggeion, vessel.] Situ- 
ated in a lymphatic (anat.). 
endolymphatic (gn'dolfmfat'ik) a. 
[Gk. endon, within ; L. lympha, 
water.] Pert, lymphatics (anat.). 
endometrium (gn'domet'rium) n. [Gk. 
endon, within ; metra, womb.] The 
mucous lining of the womb (anat.). 
endomysium (Sn'domiz'ium) n. [Gk. 
endon, within ; mys, muscle.] The 
delicate connective tissue which 

separates the muscle fibres from one 
another (anat.). 

endoneurium (gn'donu'rium) n. [Gk. 
endon, within ; neuron, nerve.] The 
delicate connective tissue holding 
together and supporting the nerve 
fibres within the funiculus (anat.). 
endoparasite (en'dopar'aslt) n. [Gk. 
endon, within ; para, beside ; sitos, 
food.] Any organism living par- 
asitically in another (biol.). 
endoperidium (en'dopSrid lum) n. 
[Gk. endon, within ; peridion, little 
pouch.] The inner layer of coat of 
peridium (bot.). 

endophragm (gn'dofram) n. [Gk. 
endon, within ; phragma, fence.} A 
septum formed by the cephalic and 
thoracic apodemes in Crustacea 

endophragmal (en'dofrag'mal) a. [Gk. 
endon, within ; phragma, fence.] 
Belonging to or pert, the endo- 
phragm (zool.). 

endophyte (gn'dofit) n. [Gk. endon, 
within ; phyton, plant.] A plant 
growing within another, either as 
parasite or otherwise (bot.). 
endophytic (en'dofit'ik) a. [Gk. 
endon, within \phyton, plant.] Living 
in the cavities of other plants (bot.). 
endoplasm (Sn'doplazm) n. [Gk. 
endon, within ; plasma, something 
moulded.] The endosarc, or inner 
portion of the protoplasm in a cell 

endoplastule (gn'doplas'tul) n. [Gk. 
endon, within ; plastos, moulded.] 
The micronucleus of certain Protists 

endopleura (Sn'ddploo'ra) n. [Gk. 
endon, within ; pleura, side.] The 
inner seed-coat (bot.). 
endopleurite (gn'doploo'rit) n. [Gk. 
endon, within ; pleura, side.] The 
epimeral portion of the apodeme 

endopodite (gndop'odit) n. [Gk. 
endon, within ; pous, foot.] The 
inner or mesial branch of a bi- 
ramous crustacean limb, or the only 
part of the biramous limb remaining 

endoral (findo'ral) a. [Gk. endon, 
within ; L. os, mouth.] Pert. 
structures situated in the vestibule 
of certain Protozoa (zool.). 



endorhachis (gn'dora'kis) n. [Gk. 
endon, within ; rhachis, stem.] A 
layer of connective tissue lining 
the canal of the vertebral column 
and the cavity of the skull (anat.). 

endosarc (fin'dosark) n, [Gk. endon, 
within ; sarx, flesh.] See endo- 

endosiphuncle (gn'dosifung'kl) n. 
[Gk. endon, within ; L. siphunculus, 
little tube.] The tube leading from 
the protoconch to the siphuncle in 
certain Cephalopods (pal.}. 

endoskeleton (eVdoskeTeton) n. [Gk. 
endon, within ; skeletos, hard.] The 
inner skeleton as opposed to the 
exoskeleton (zoo!.). 

endosmosis (Sn'dSsmo'sTs) n. [Gk. 
endon, within ; osmos, pushing in- 
fluence.] The passage inwards 
through a permeable or semi- 
permeable membrane of a less 
concentrated solution (phys.). 

endosome (e"n'dos5m) n. [Gk. endon, 
within ; soma, body.] The chroma- 
tinic mass near the centre of a 
vesicular type of nucleus (cyt.). 

endosperm (gn'dospgrm) n. [Gk. 
endon, within ; sperma, seed.] The 
female prothallium (pot.). 

endospore (fin'dospor) n. [Gk. endon, 
within ; sporos, seed.] The inner 
coat of the sporocyst in some 
Protozoa (zoo!.) ; an asexual spore ; 
the inner coat of a spore wall 

endosporium (Sn'dospo'rium), see 

endosteal (e"nd8s'teal) a. [Gk. endon, 
within ; osteon, bone.] Pert, the 
endosteum (ana/.). 

endosternlte (eVdosteYnlt) n. [Gk. 
endon, within ; L. sternum, sternum.] 
The internal skeletal plate for the 
attachment of muscles ; a free 
skeleton situated in the prosoma 
between the alimentary canal and 
the nerve cord in Arachnids (zoo!.). 

endosttmm (gndos'teum) n. [Gk. 
endon, within ; osteon, bone.] The 
internal periosteum lining the 
cavities of bones (anaf.). 

endostosis (gn'dosto'sis) n. [Gk. 
endon, within ; osteon, bone.] Ossi- 
fication which begins in the carti- 
lage (anaf.). 

endostracum (gndos'trakum) n. [Gk. 

endon, within ; ostrakon, shell.] The 
inner layer of the shell (zoo!.). 

endostyle (en'dostll) n. [Gk. endon, 
within ; stylos, pillar.] A band 
of thickened epithelium on the 
oesophageal wall of a Tornaria ; 
two ventral longitudinal folds separ- 
ated by a groove in the pharynx 
of the Tunicates ; a longitudinal 
groove lined by ciliated epithelium 
on the ventral wall of the pharynx 
of Amphioxus (zoo!.). 

endotheca (gn'dothe'ka) n. [Gk. 
endon, within ; theke, box.] The 
whole system of dissepiments in any 
given calyx of a coral ; the oval 
surface of any Cystidea (zool.). 

endothecial (gn'dothe'ktal, -shial) a. 
[Gk. endon, within ; theke, box.] 
Pert, the endothecium ; with asci 
in an ascocarp (bot.). 

endothecium (gn'dothe'ktum, -shium) 
n. [Gk. endon, within ; theke, box.] 
The central region of an epibasal 
octant of the oospore of liverworts 
and mosses ; the inner lining of an 
anther (dot.). 

endothelium (Sn'dothe'llum) n. [Gk. 
endon, within ; thele, nipple.] A 
squamous epithelium which lines 
the serous cavities, the heart, blood, 
and lymphatic vessels (anat.). 

endothorax (e'n'dotho'raks) n. [Gk. 
endon, within ; thorax, chest.] The 
apodeme system in a crustacean 
thorax (zoo!.). 

end-plates, the ramified expansions 
within the muscular fibre which 
form the ends of a motor nerve 

end-sac, the sac-like vestigial portion 
of the coelom in the excretory glands 
of certain Crustacea (zoo!.). 

endysis (gndl'sls) n. [Gk. endysts, 
putting on.] The development of 
a new coat (zoo!.). 

energesis (6n'6rj e'sts) n. [Gk. energein, 
to be active.] The process by which 
energy is liberated through kata- 
bolic action (phys.). 

energld (6n'6rjld) n. [Gk. en, in ; 
ergon, work.] Any living uni- 
nucleated protoplasmic unit with 
or without a cell wall (bot.) 

enervose (eneVvos) a. [L. ex, with- 
out ; nervus, sinew.] Having no 
veins, appl. certain leaves (bot.). 




engraved (engraVd)<2. [h..S.grafan,io 
dig.] With irregular linear grooves 
on the surface (zool.). 

ensiform (en'siform) a. [L. ensis, 
sword ; forma, shape.] Sword- 
shaped (biol.). 

entelechy (gnteTe"ki) . [Gk. en, in ; 
telos, end ; echein, to hold.] The 
realisation of forms in plant and 
animal life which have the power 
of reproducing their kind (biol.). 

entepicondylar (gntSpikon'dilar) a. 
[Gk. entos, within ; epi, upon ; 
kondylos, knob.] Pert, the lower 
or condylar end of the humerus 

enteric (Sn'tgrlk) a. [Gk. enteron, 
gut.] With an alimentary canal 

enterocoel (6n't6rosel') n. [Gk. 
enteron, gut ; koilos, hollow.] A 
coelom which has arisen either as 
a pouch-like outgrowth of the arch- 
enteric cavity, or as a series of such 
outgrowths (emb.). 

enteron (en'teron) n. [Gk. enteron, 
gut.] The alimentary tract (zool.). 

entire (entlr') a. [M.E. enter, un- 
touched.] With a continuous 
margin ; appl. leaves (dot.). 

entoblast (en'toblast) n. [Gk. entos, 
within ; blastos, bud.] The endo- 
derm ; the nucleolus (zool.). 

entobranchiate (fin'tobrang'kTat) a. 
[Gk. entos, within ; brangchia, gills.] 
Having internal gills (zool.). 

entobronchlum (Sn'tobrong'klum) n. 
[Gk. entos, within ; brongchos, wind- 
pipe.] The dorsal secondarybranch 
of the bronchus in birds (anat.). 

entobronchus(e'n'tobrong'kus), ento- 

entochondrostosis (gn'tokondrosto'- 
sis) n. [Gk. entos, within ; chondros, 
cartilage ; osteon, bone.] Ossifica- 
tion from within outwards (zool.). 

entocodon (gn'tb'ko'don) n. [Gk. 
entos, within ; kodon, bell.] The 
lens-shaped mass of cells in the 
development of a medusoid which 
sink below the level of the super- 
ficial ectoderm, and ultimately 
develop a cavity (zool.). 

entocoel (gn'tosel) n. [Gk. entos, 
within ; koilos, hollow.] The space 
enclosed by a pair of mesenteries 
in the Anthozoa (zool.). 

entocondyle (en'tokon'dil) n. [Gk. 
entos, within ; kondylps, knob.] The 
condyle on the mesial surface of a 
bone (anat.). 

entoconid (gn'tb'ko'nid) n. [Gk. entos, 
within ; konos, cone.] The postero- 
internal cusp of a lower molar (zool.). 

entocuneifonn (n'tbkune'iform) n. 
[Gk. entos, within ; kuneos, wedge ; 
L.forma, shape.] The most internal 
of the distal row of tarsal bones 

entocyemate (gn'tosie'mat) a. [Gk. 
entos, within ; kyema, embryo.] With 
embryos having amnion and allan- 
tois (smb.). 

entoderm, see endoderm. 

entodermal, see endodermal. 

entogastric (en'togas'trik) a. [Gk. 
entos, within ; gaster, belly.] Pert. 
interior of stomach ; appl. gastric 
budding in Medusae (zool.). 

entoglossal (Sn'toglos'al) a. [Gk. 
entos, within ; glossa, tongue.] Lying 
in the substance of the tongue 

entomology (en'tb'morojT) n. [Gk. 
entomon, insect ; logos, discourse.] 
That portion of zoology dealing 
with Insects (zool.). 

entomophilous (Sn'tomof ilus) a. [Gk. 
entomon, insect ; philein, to love.] 
Pollinated by the agency of insects 

entophyte (en'toflt) n. [Gk. entos, 
within ; phyton, plant.] Endophyte. 

entoplastron (gn'toplas'tron) n. [Gk. 
entos, within ; F. plastron, breast- 
plate.] The anterior median plate 
in the chelonian plastra, often called 
the episternum, and probably homo- 
logous with the interclavicle of other 
Reptiles (zool.). 

entopterygold (fin'topteVigoid) n. 
[Gk. entos, within ; pteryx, wing ; 
eidos, resemblance.] The inner 
bone adjoining the palate in Fishes 

entosphere (Sn'tosfer) n. [Gk. entos, 
within ; sphaira, globe.] The inner 
portion of the attraction sphere 

entosternite (gn'tostSr'nlt) n. [Gk. 
entos, within ; sternon, breast.] 

entosternum (SntostSr'num) n. [Gk. 
entos, within ; sternon, breast.] The 



entoplastron ; an internal process 
of the sternum of numerous Arthro- 
pods (zool.). 

entoturbinals (e'n'totur'binalz) n. plu. 
[Gk. entos, within ; L. turbo, whorl.] 
One of the divisions of the ethmo- 
turbinals (zool.). 

entovarlal (Sn'tova'rial) a. [Gk. entos, 
within ; L. ovum, egg.] Pert, canal 
formed in the ovaries of certain 
Fishes by the insinking and closure 
of a groove formed by the covering 
epithelium (zool.). 

entozoa (gn'tozo'a) n. plu. [Gk. entos, 
within ; zoon, animal.] A general 
name for all internal parasites 

entozoic (gn'tozo'ik) a. [Gk. en/as, 
within ; zoon, animal.] Living 
within the body or substance of 
another plant or animal (zool.). 

entrochite (gntro'klt) n. [Gk. en, in ; 
trochos, wheel.] The joint of the 
fossil stem of a stalked Crinoid(/a/.). 

envelope (gn'vgldp) n. [F. enveloppe, 
covering.] One of the outer cover- 
ings of an egg (zool.} ; any surround- 
ing structure, e.g. floral envelop 

environment (gnvl'ronme'nt) n. [F. 
environ, about.] The sum-total of 
the external influences acting on 
an organism (bio/.). 

enzootic (gn'zoSt'ik) a. [Gk. en, in ; 
zoon, animal.] Afflicting animals 

enzyme (en'zfm) n. [Gk. en, in ; 
zyme, leaven.] A chemical or un- 
organized soluble ferment (phys.}. 

Eocene (e'osen) n. [Gk. eos, dawn ; 
kainos, recent.] The earliest or 
oldest division of the Tertiary 
system (pal.}. 

Eogaea (e'oje'a) n. [Gk. eos, dawn ; 
gaia, land.] A zoogeographical divi- 
sion including Africa, S. America, 
and Australasia ; cf. Caenogaea. 

eosinophile (e'osTn'ofil) a. [Gk. eos, 
dawn ; philein, to love.] Appl. 
cells which readily stain a brilliant 
red colour when treated with a 
mixed stain containing eosin (phys.). 

epacme (gpSk'me) n. [Gk. epi, upon ; 
akme, point.] The stage in the 
phylogeny of a group just previous 
to its reaching its summit (pal.). 

epalaceous (e'pala'shus) a. [L. ex, 

without \pala, shovel.] Not spade- 
shaped (bot.). 

epaleaceous (e'palea'shus) a. [L. ex, 
without ; palea, chaff.] With re- 
ceptacles which do not contain 
chaff (bot.). 

epalpate (epal'pat) a. [L. ex, without ; 
palpus, palp.J Not furnished with 
palpi (zool.). 

epapillate (epSp'ilat) a. [L. ex, with- 
out ; papilla, nipple.] Not having 
papillae (zool.). 

epapophyals (gp'apof'isis) n. [Gk. 
epi, upon ; apophysis, offshoot.] A 
median process arising from the 
centre of the neural arch of a 
vertebra (anat.). 

eparterial (ep'arte'rial) a. [Gk. epi, 
upon ; L. arteria, artery.] Situated 
above an artery ; appl. branch of 
right bronchus (anat.). 

epaulettes (6p'616ts) n. plu. [F. 
tyaule, shoulder.] Branched or 
knobbed processes projecting from 
the outer side of the oral arms 
of many Scyphozoa ; horizontally 
placed crescentic ridges of cilia in 
the Echinopluteus (zool.). 

epaxlal (gpak'slal) a. [Gk. epi, upon ; 
L. axis, axis.] Above the axis ; 
usually appl. axis formed by verte- 
bral column (anat.). 

epedaphic (ep'edafik) a. [Gk. epi, 
upon ; edaphos, soil.] Pert, climatic 
conditions (bot.). 

epencephalon (6p'6nk6f'alon, -seT-) n. 
[Gk. epi, upon ; engkephalon, the 
brain.] The cerebellum (anat.). 

ependyma (gpgn'dima), ependyme 
(e'pe'ndlm 7 ) n. [Gr. ependyma, outer 
garment/] The layer of cells lining 
the cavities of the brain and spinal 
cord (anat.). 

ependymal (gpgn'dimSl) a. [Gk. epen- 
dyma, outer garment.] Pert, epen- 

ephebic (gfe'blk) a. [Gk. epi, upon ; 
hebe, puberty.] Pert, stage in 
phylogeny between the early, or 
childhood stage and the old-age 
stage of a group (pal.). 

ephemerals (ef gm'gralz) n. plu. [Gk. 
ephemeras, daily.] Annual plants 
with duration of life-cycle so 
shortened as to enable several 
generations to follow one another 
during a single season (bot.). 




ephippium (efip'ium) n. [Gk. epi, 
upon ; hippos, horse.] The pituitary 
fossa, or fossa hypophyseos of the 
sphenoid (anat) ; a thickened and 
indurated part of the shell which 
separates from the rest at ecdysis 
and forms a protective case for the 
eggs in certain Cladocera (zool). 

ephyra (eTira) n. [Gk. Ephyra, a 
nymph's name.] The small free- 
swimming jelly-fish stage of certain 
Scyphozoa, produced by strobilation 
of the Scyphistoma (zool.). 

ephyrula (6f ir'ula), ephyra. 

epibasal (ep'iba'sal) a. [Gk. epi, upon ; 
L. basis, base.] Pert, upper segment 
of an oospore, ultimately giving rise 
to the shoot (hot.), 

epibenthos (gp'ibgn'thos) n. [Gk. epi, 
upon ; benthos, depths.] Fauna and 
flora found between the low-water 
mark and the'hundred fathoms' line 

epiblast (gp'iblast) n. [Gk. epi, upon ; 
blastos, bud.] The outer layer of the 
gastrula ; the ectoblast (emb). 

eplblema (gp'ible'ma) n. [Gk. epi- 
blema, cover.] The outermost layer 
of the root-tissue (bot.). 

epibolic (gp'ibol'ik) a. [Gk. epi, upon ; 
ballein, to throw.] Growing so as to 
cover over ; appl. type of gastrula- 
tion (emb.). 

epiboly (epib'oli) n. [Gk. epi, upon ; 
ballein, to throw.] Growth of one 
part over another in embryonic 
stages (emb.). 

eplbranchial (ep'ibrang'kial) a. [Gk. 
epi, upon ; brangchia, gills.] Pert. 
the second upper element in a 
branchial arch (zool). 

epicalyx (ep'Ika'liks) n. [Gk. epi, 
upon ; kalyx, cup.] The stipules, 
fused in pairs, producing an ap- 
parent outer or extra calyx ; a 
structure just below the calyx pro- 
duced by the aggregation of bracts 
or bracteoles (bot). 

epicanthus (gp'ikan'thus) n. [Gk. 
epi, upon ; kanthos, corner.] A 
prolongation of the upper eyelid 
over the inner angle of the eye 

epicardium (ep'ikar'dium) n. [Gk. 
epi, upon ; kardia, heart.] The 
visceral part of the pericardium 
(anat) ; a tubular prolongation of 

the branchial sac in many Ascidians, 
which takes part in budding (zool.). 
epicarp (ep'fkarp) n. [Gk. epi, upon ; 
karpos, fruit.] The outer layer of 
the pericarp (bot). 

epicentral (ep'isgn'tral) a. [Gk. epi, 
upon ; kentron, centre.] Attached 
to or arising from the vertebral 
centra ; appl. usually to inter- 
muscular bones (anat). 
epicerebral (ep'iser'gbral) a. [Gk. 
epi, upon ; L. cerebrum, brain.] 
Situated above the brain (anat.). 

epichilium (ep'ikll'ium) n. [Gk. epi, 
upon ; cheilos, lip.] The terminal 
lobe of the lower petal of an 
orchid (bot.). 

epichordal (ep'ikor'dal) a. [Gk. epi, 
upon ; chorde, cord.] Upon the 
notochord ; appl. vertebrae in which 
the ventral cartilaginous portions 
are almost completely suppressed 

epicoele (ep'isel) n. [Gk. epi, upon ; 
koilos, hollow.] The cavity of the 
mid-brain in the lower vertebrates ; 
the cerebellar cavity (anat) ; a peri- 
visceral cavity formed by invagina- 
tion (zool). 

epicoelia (ep'ise'lia) n. [Gk. epi, 
upon ; koilia, cavity.] Epicoele. 

epicondylar (gp'lkon'dilar) a. [Gk. 
epi, upon ; kondylos, knob.] Pert. 
the epicondyle (zool). 

epicondyle (ep'ikon'dil) n. [Gk. epi, 
upon ; kondylos, knob.] The outer 
protuberance at the lower or distal 
end of the humerus (anat). 

epicoracoid (Sp'ikor'akoid) a. [Gk. 
epi, upon ; korax, crow ; eidos, re- 
semblance.] Pert, an element 
usually cartilaginous in nature at 
the sternal end of the coracoid in 
Amphibians, Reptiles, and Mono- 
tremes (zool). 

epicormic (ep'ikor'mik) a. [Gk. epi, 
upon ; kormos, trunk of a tree.] 
Growing from a dormant bud 

epicotyl (ep'ikot'il) n. [Gk. epi, upon ; 
kotyle, vase.] The axis of a plumule 

epicotyledonary (ep'lkot'iled'onari) a. 
[Gk. epi, upon ; kotyle, vase.] Above 
the cotyledons (hot). 

epicoxite (ep'ikok'sTt) n. [Gk. epi, 
upon ; L. coxa, hip.] A small 




process at the posterior end of the 
toothed part of the coxae of the 
second, third, fourth, and fifth pairs 
of appendages in the Eurypterida 

epicranial (ep'ikra'nial) a. [Gk. epi, 
upon ; kranion, skull.] Pert. 
cranium ; appl. muscles, bones, 
etc. (anat.). 

epicranlum (gp'ikra'nium) n. [Gk. 
epi, upon ; kranion, skull.] The 
region between and behind the 
eyes in an insect's head (zool) ; 
the structure covering the cranium 

epicritic (ep'ikrit'ik) a. [Gk. epi, 
upon ; krinein, to judge.] Pert. 
return and accurate localization of 
elaborate sensations after an opera- 
tion (phys.). 

epicyte (Ip'islt) n. [Gk. epi, upon ; 
kytos, hollow.] The external layer 
of the ectoplasm in certain Protozoa 

epidemes (Sp'idemz) n. plu. [Gk. 
epi, upon ; demas, body.] In 
certain insects, small pieces closely 
related with the articulation of the 
wings (zool.). 

epidermis (gp'Tder'mis) n. [Gk. epi, 
upon ; derma, skin.] The outer- 
most protective layer of stems, 
roots, and leaves, occasionally it 
may be the outer layer of the 
ground tissue (hot.) ; the external 
layer of the skin, a non-vascular 
stratified epithelium of ectodermic 
origin ; the single layer of ectoderm 
in many invertebrates (zool.). 

epididymis (ep'idid'imis) n. [Gk. epi, 
upon ; didymos, testicle.] A mass 
at the back of the testicle composed 
chiefly of the vasa efferentia ; gener- 
ally speaking, the greatly coiled 
anterior end of the Wolffian duct 
(anat., zool.). 

epidural (ep'idu'ral) a. [Gk. epi, upon ; 
L. dura, hard.] Pert, dura mater ; 
appl. space between the dura mater 
and the wall of the vertebral column 

epigamic (ep'fgam'ik) a. [Gk. epi, 
upon ; gamos, marriage.] Tending 
to attract the opposite sex (zool.). 

epigainous (epig^amus) a. [Gk. epi, 
upon ; gamos, marriage.] Designat- 
ing that stage in polychaete worms 

in which the immature forms be- 
come heteronereid, whilst the sexual 
elements are ripening (zool.). 

epigaster (ep'Igas'ter) n. [Gk. epi, 
upon ; gaster, belly.] That part of 
the embryonic intestine which later 
develops into the gut (emb.). 

epigastric (gp'igas'trik) a. [Gk. epi, 
upon ; gaster, belly.] Pert, anterior 
wall of the abdomen ; middle region 
of the upper zone of the artificial 
divisions of the abdomen (anat). 

epigastrium (Sp'Tgas'trium) n. [Gk. 
epi, upon ; gaster, stomach.] The 
epigastric region (anat.) ; the sternal 
portions of the meso- and meta- 
thorax of insects (zool.). 

epigeal (gp'iie'al) a. [Gk. epi, upon ; 
gaia, land.] Living near the ground, 
appl. insects (zool.) ; borne above 
the ground, appl. cotyledons when 
they form first foliage leaves (dot.). 

epigenesis (ep'ijen'e'sis) n. [Gk. epi, 
upon ; gignesthai, to be born.] The 
theory of generation, that the em- 
bryo is an entirely new creation, 
not a mere unfolding of preformed 
structures (biol.). 

epigeous (gp'Tje'us), see epigeal 

epiglottis (ep'iglot'is) n. [Gk. epi, 
upon ; glotta, tongue.] A thin leaf- 
shaped lamella of fibro-cartilage, 
yellowish in colour, between the 
root of the tongue and the entrance 
to the larynx (anat) ; the epistome 
in Polyzoa ; the epipharynx in In- 
sects (zool.). 

a. [Gk. epi, upon ; gnathos, jaw.] 
Having the upper jaw longer than 
the lower (zool.). 

epigonium (e'p'Igo'nlum) n. [Gk. epi, 
upon ; gone, seed.] The young 
sporangial sac in the Liverworts 

epigynous (gpij'mus) a. [Gk. epi, 
upon ; gyne, woman.] Having the 
various whorls adnate to the ovary, 
thus apparently inserted in the ovary 

epigyny (epij'inl) n. [Gk. epi, upon ; 
gyne, woman.] The condition of 
having the whorls apparently in- 
serted in the ovary (bot.). 

epihyal (gp'ihi'al) a. [Gk. epi, upon ; 
hyoeidcs, Y-shaped.] Pert, the upper 




portion of the ventral part of the 
hyoid arch ; n. the upper element 
of the ventral portion (zool.}. 

epilabrum (ep'ilab'rum) n. [Gk. 'epi, 
upon ; L. labrum, lip.] A process 
at the side of the labrum in Myria- 
pods (zool.}. 

epimandibular (ep'imandlb'ular) a. 
[Gk. epi, upon ; L. mandibulum, 
jaw.] Pert, a bone in the lower 
jaw of vertebrates (zool.}. 

epimeral (epim'eral) a. [Gk. epi, 
upon ; meros, part.] Pert, epimeron. 

epimere (ep'imer) n. [Gk. epi, upon ; 
meros, part.] The upper region, 
or dorsal muscle-plate of the meso- 
thelial wall (smb.}. 

epimerite (epim'e'rlt) n. [Gk. epi, 
upon ; meros, part.] The deciduous 
portion of the protomerite in certain 
Gregarines (zool.}. 

epimeron (epim'eron) n. [Gk. epi, 
upon ; meros, part.] A portion of 
the pleuron in insects which may 
be posterior or nearly as far forward 
as the episternum ; a portion of the 
arthropod segment between the 
tergum and the limb insertions 

epimorphosis (e'p'imor'fosis) n. [Gk. 
epi, upon ; morphe, change.] That 
type of regeneration in which a 
proliferation of new material pre- 
cedes the development of the new 
part (biol.}. 

epimysium (ep'imlz'ium) n. [Gk. epi, 
upon ; mys, muscle.] The sheath 
of areolar tissue which invests the 
entire muscle ; cf. perimysium 

epinasty (ep'inas'ti) n. [Gk. epi, upon ; 
nastos, pressed close.] The more 
rapid growth of the upper surface 
of a dorso-ventral organ, e.g. a 
leaf, thus causing an unrolling or 
downward curvature (bot.}. 

epineural (ep'inu'ral) a. [Gk. epi, 
upon ; neuron, nerve.] Arising 
from the neural arch of a vertebra 
(anat.} ; pert, canal immediately 
below the radial nerve cord in the 
Ophiuroidea, which represents the 
missing ambulacral groove (zool.}. 

epineurium (ep'mu'rium) n. [Gk. 
epi, upon ; neuron, nerve.] The 
external sheath of a nerve cord 

epiotic (ep'iot'ik) a. [Gk. epi, upon ; 
ous, the ear.] Pert, the upper ele- 
ment of the bony capsule of the ear 

epiparasite (ep'ipar'asit) n. [Gk. epi, 
upon ; para, beside ; sites, food.] 

epipetalous (ep'ipet'alus) a. [Gk. cpi, 
upon ; petalon, petal.] Having the 
stamens inserted on the petals (bot.}. 

epipharyngeal (ep'ifaYinje'al, ep'i- 
farin'jeal) a. [Gk. ept, upon ; 
pharyngx, throat.] Pert, the upper 
or dorsal aspect of the pharynx 

epipharynx (ep'ifa'ringks) n. [Gk. 
epi, upon ; pharyngx, throat.] A 
projection on the roof of the mouth 
cavity of certain insects ; the mem- 
branous lining of labrum and 
clypeus drawn out with the labrum 
to form a piercing organ, as in 
Diptera (zool.}. 

epiphragm (ep'ifram) n. [Gk. epi- 
phragma, covering.] A layer of 
hardened mucous matter, or a cal- 
careous plate, closing the opening 
of certain gastropod shells (zool.} ; 
the membrane which closes the 
capsule in certain Mosses ; a 
closing membrane in the sporo- 
phores of certain Fungi (bot.}. 

epiphysial (ep'ifiz'ial) a. [Gk. epi, 
upon ; phyein, to grow.] Pert, or 
similar to the epiphysis (zool.}. 

epiphysis (epif'isis) n. [Gk. epi, upon ; 
phyein, to grow.] Any part or pro- 
cess of a bone which is formed from 
a separate centre of ossification and 
later fuses with the bone ; the pineal 
body (anat., zool.} ; a stout bar 
firmly fused to the alveolus of each 
jaw and articulating with the rotulae 
in sea-urchins ; certain of the pro- 
cesses on the tibia of insects (zool.}. 

epiphyte (ep'ifit) n. [Gk. epi, upon ; 
phyton, plant.] Plant which lives 
on other plants, but is not parasitic 

epiphytic (ep'ifit'ik) a. [Gk. epi, 
upon ; phyton, plant.] Pert, or 
similar to an epiphyte (bot.}. 

epiphytotic (ep'ifitot'ik) a. [Gk. epi y 
upon ;phytoft, plant.] Pert, disease 
epidemic in plants (bot.}. 

epiplankton (ep'iplang'kton) n. [Gk. 
epi, upon ; plangktos, wandering.] 




That portion of the plankton from 
the surface to the hundred fathoms 
line (zool.}. 

eplplasm (Sp'iplazm) n. [Gk. epi, 
upon ; plasma, something moulded.] 
Cytoplasm of a brood mother-cell 
remaining over unused in brood 
formation (biol.}. 

epiplastron (p'iplas'tron) n. [Gk. 
epi, upon ; F. plastron, breast-plate.] 
One of the anterior pair of bony 
plates in the plastron of Chelonians 

epipleura (ep'iploo'ra) n. [Gk. epi, 
upon ; pleuron, rib.] One of rib- 
like structures in Teleosts which 
are not preformed in cartilage ; an 
uncinate process in birds ; the 
turned down outer margin of the 
elytra of certain beetles (zool.}. 

epiploic (gp'iplo'ik) a. [Gk. epiploon, 
caul of the entrails.] Pert, the 

epiploic foramen, the opening be- 
tween the bursa omentalis and the 
large sac of the peritoneum ; the 
foramen of Winslow (anat.}. 

epiploon (gp'iplo'on) n. [Gk. epiploon, 
caul of the entrails.] The great 
omentum (anat.} ; insect adipose 
tissue (zool.}. 

epipodial (ep'ipo'dial) a. [Gk. epi, 
upon ; pous, foot.] Pert, the epi- 

epipodite (epip'odij) n. [Gk. epi, 
upon ; pous, foot.] A process 
arising from the basal joint of the 
crustacean limb and usually ex- 
tending into the gill chamber (zool.}. 

eplpodium (Sp'ipo'dTum) n. [Gk. epi, 
upon ; pous, foot.] The embryonic 
leaf-lamina (bot.} ; ridge or fold 
running along the entire edge of the 
creeping sole of the foot of Gastro- 
pods, often beset with papillae ; the 
raised ring on an ambulacral plate 
surrounding the two pores through 
which the tube-feet project in 
Echinoidea (zool.}. 

epiprecoracoid (ep'iprekor'akoid) ;/. 
[Gk. epi, upon ; L. pre, before ; Gk. 
tnnur, crow ; eidos, resemblance.] 
A small cartilage at the ventral 
end of the precoracoid in some 
turtle pectoral girdles (zool.}. 

epipteric (ep'ipter'ik) a. [Gk. epi % 
upon ; pteron, wing.] Pert, or 

shaped like, or placed above the 
wing ; appl. a small bone in the 
skull between the parietal and the 
sphenoidal ala (anat.}. 

epipterygoid (ep'iptgr'igoid) n. [Gk. 
epi, upon ; pteryx, wing.] A small 
bone extending nearly vertically 
downwards from the prootic to the 
pterygoid ; also called columella 

epipubic (ep'ipu'blk) a. [Gk. epi, 
upon ; L. pubes, adult.] Pert, or 
borne upon the pubis ; appl. 
certain cartilages or bones princi- 
pally in marsupials (zool.}. 

epipubis (ep'fpu'bis) n. [Gk. epi, 
upon ; L. pubes, adult.] An un- 
paired cartilage or bone borne 
anteriorly on the pubis (zool.}. 

epirhizous (epTrfzus) a. [Gk. epi, 
upon ; rhiza, root.] Growing upon 
a root (bot.}. 

episepalous (gp'isep'alus) a. [Gk. epi, 
upon ; sepalon, sepal.] Adnate to 
the sepals (bot.}. 

episkeletal (ep'iskel'gtal) a. [Gk. epi, 
upon ; skeletos, hard.] Outside the 
endoskeleton (zool.}. 

episperm (Sp'isperm) n. [Gk. epi, 
upon ; sperma, seed.] The testa or 
outer coating of the seed (bot.}. 

episporangium (gp'isporan'jTum) n. 
[Gk. epi, upon ; sporos, seed ; 
anggeion, vessel.] An indusium 

epispore (ep'ispor) n. [Gk. epi, upon ; 
sporos, seed.] The outer layer of 
the wall of a sporocyst (zool.}. 

episternalia (6p'ist6rna'lia) n. plu. 
[Gk. epi, upon ; sternon, breast- 
bone.] Two small elements pre- 
formed in cartilage frequently inter- 
vening in development between the 
clavicles and the sternum, and 
ultimately fusing with the sternum 

episternite (ep'isteYnit) n. [Gk. epi, 
upon ; sternon, breast-bone.] One 
of the portions of an ovipositor 
formed from the side portions of a 
somite (zool.}. 

episternum (ep'isteYnum) . [Gk. 
epi, upon ; sternon, breast-bone.] 
The interclavicle ; also applied to 
an anterior cartilaginous element 
of the sternum ; a lateral division 
of an arthropod somite, usually 




above the sternum and more an- 
teriorly placed than the epimeron 

epistoma (ep'isto'ma) n. [Gk. epi, 
upon ; stoma, mouth.] The region 
between the antenna and the mouth 
in Crustacea ; a small lobe over- 
hanging the mouth in the Polyzoa 
and containing a part of the body 
cavity ; that portion of the insect's 
head immediately behind the 
labrum ; a portion of the rostrum 
of certain Diptera (zool.). 

epistome, see epistoma. 

epistrophe (epis'trofe) n. [Gk. epis- 
trophe, turning towards.] The 
position assumed by the chloro- 
plasts along the outer and inner 
walls when exposed to diffuse light 

epistropheus (ep'istro'feus, ep'istro'- 
fyus) n. [Gk. epistropheus, turning.] 
The axis vertebra (anat}. 

epithalamus (ep'ithal'amus) n. [Gk. 
epi, upon ; thalamos, chamber.] 
The trigonum habenulae, the pineal 
body and the posterior commissure 
of the brain (anat.). 

epithalline (ep'ithal'ln) a. [Gk. epi, 
upon ; thalla, stem.] Growing upon 
the thallus (hot.}. 

epitheca (gp'ithe'ka) n. [Gk. epi, 
upon ; theke, cup.] An external 
layer surrounding the lower part 
of the theca in many Corals (zool}. 

epithecium (e"p'ithe'kium, gp'ithe'- 
shtum) n. [Gk. epi, upon ; theke, 
cup.] The surface of the spore- 
cases in Lichens and Fungi (dot.). 

epithelial (ep'ithe'lial) a. [Gk. epi, 
upon ; t/tele, nipple.] Pert, epithe- 

epithelium (ep'lthe'lium) n. [Gk. 
epi, upon ; thele, nipple.] Any 
cellular tissue covering a free 
surface or lining a tube or cavity 

epithem (ep'Tthgm) n. [Gk. eft, 
upon ; tithenai, to put.] A group 
of specialized colourless paren- 
chyma cells surrounding a space 
in the tissue of a plant and forming 
a hydathode (bot.) ; an excrescence 
on the beak of birds (zool.). 

epithema, see epithem. 

epitheme, see epithem. 

epitokous (epTt'b'kus) a. [Gk. epi, 

upon ; tokos, birth.] Designating 
the heteronereid stage of certain 
Polychaetes (zool.). 

epitrichial (ep'itrik'ial) a. [Gk. epi, 
upon ; thrix, hair.] Pert, or re- 
sembling the epitrichium (emb.). 

epitrichium (ep'itrlk'ium) n. [Gk. 
epi, upon ; thrix, hair.] An outer 
layer of the epidermis in the foetus 
of many mammals, usually shed 
before birth (emb.}. 

epitrochlea (gp'itrok'lea) n. [Gk. 
epi, upon ; trochos, wheel.] The 
inner condyle at the distal end of 
the humerus (anat.). 

epitympanic (e'p'itimpan'ik) a. [Gk. 
epi, upon ; L. tympanum, kettle- 
drum.] Situated above the tympa- 
num (zool.). 

epixylous (ep'iksi'lus, epik'siliis) a. 
[Gk. epi, upon ; xylon, wood.] 
Growing upon wood (bot.). 

epizoic (ep'izo'ik) a. [Gk. epi, upon ; 
zoon, animal.] Pert, animals living 
on or attached to the body of 
another animal (zool.). 

epizoon (gp'izo'on) ;;. [Gk. epi, upon ; 
zoon, animal.] An animal living 
on another ; an external parasite 

epizootic (ep'izoot'ik) a. [Gk. epi, 
upon ; zoon, animal.] Common 
among animals (zool.). 

epizygal (ep'izl'gal) n. [Gk. epi, 
upon ; zygon, yoke.] The upper 
ossicle in a syzygial pair of 
brachials or columnars in the 
Crinoids (zool.}. 

eponychium (ep'onik'ium) . [Gk. 
epi, upon ; onyx, nail.] The thin 
cuticular fold which overlaps the 
lunula of the nail (anat.) ; the 
dorsal portion of a neonychium 

epoophoron (gp'ooftiron) n. [Gk. 
epi, upon ; oon, egg ; p herein, to 
bear.] A rudimentary organ, the 
remains of the WolfHan body of 
the embryo, lying in the meso- 
salpinx between the ovary and the 
uterine tube (anat.). 

equal (e'kwal) a. [L. aequalis, equal.] 
Having the portions of the lamina 
equally developed on the two sides 
of the midrib ; appl. leaves (bot.). 

equation division, in mitosis, by 
the longitudinal splitting of the 




chromatin thread all the ancestral 
germ-plasms are equally distributed 
in the daughter nuclei (cyt.}. 
equatorial (ek'wato'rial) plate, the 
group of chromosomes lying at 
the equator of the spindle during 
mitosis (cyt.}. 

equiblradlate (ek'wiblra'dtat) a. [L. 
aeguus, equal ; bis, twice ; radius, 
radius.] With two equal rays 

equicellular (ek'wiseTular) a. [L. 
aequus, equal ; cellula, cell.] Com- 
posed of equal cells (zool.}. 

equilateral (ek'wilat'e'ral) a. [L. 
aequus, equal ; latiis, side.] Hav- 
ing the sides equal ; appl, shells 
which are symmetrical about a 
transverse line drawn through the 
umbo (zool.}. 

equitant (gk'witant) a. [L. equitare, 
to ride.] Having the bases over- 
lapping, saddlewise, the leaves 
above them (bot.}. 

equlvalve (ek'wivalv') a. [L. aequus, 
equal ; valva, valve.] Having the 
two halves of the shell exactly 
alike in form and size (zool.}. 

erect (erekt') a. [L. erigere, to raise 
up.] Not decumbent (bot.}. 

erectile (ereVtil) a. [L. erigere, to 
raise up.] Capable of being erected 

erectile tissue, a tissue capable of 
being made rigid and dilated by 
the distention of the blood-vessels 
within it (anat.}. 

erection (ereVshiin) n. [L. erigere, 
to raise up.] The state of a part 
which has become swollen and 
distended through the accumula- 
tion of blood in the erectile tissue 

erector (ergk'tor) n. [L. erigere, to 
raise up.] A muscle which raises 
up an organ or part (anat.}. 

eremochaetous (eYemoke'tus) a. 
[Gk. eremos, lonely ; chaeta, bristle.] 
Having no regularly arranged 
system of pointed bristles ; appl. 
flies (sool.}. 

ergaloid (eYgaloid) a. [Gk. ergates, 
worker.] Having the adults sexu- 
ally capable though wingless (zool.}. 

ergastoplasm (grgas'toplazm) n. [Gk. 
ergazesthai, to work ; plasma, some- 
thing moulded.] Archoplasm (biol.}. 

ergatandrous (grgatan'driis) a. [Gk. 
ergates, worker; aner, man.] Hav- 
ing worker-like males (zool.}. 

ergatogynous (eYgatqj'Tnus) a. [Gk. 
ergates, worker ; gyne, woman.] 
Having worker-like females (zool.}. 

ergot (eVgot) n. [O.K. argot, spur.] 
A small bare patch found on the 
limbs of the horse-tribe, represent- 
ing the last remnant of the naked 
palm of the hand and sole of the- 
foot (anat.}. 

eriophyllous (eYiofil'us) a. [Gk. 
erion, wool ; phyllon, leaf.] Having 
leaves with a cottony appearance 

erose (eros') a. [L. erodere, to wear 
away.] Having the margin 
irregularly notched (bof.). 

erosion (erS'zhun) n. [L. erodere, to 
wear away.] Decay which usually 
starts at the apex of many gastro- 
pod shells (zool.}. 

erostrate (eros'trat) a. [L. ex, with- 
out ; rostrum, beak.] Having no 
beak ; appl. anthers (bot.}. 

ersaeome (eYseorh) n. [Gk. erse, 
young.] The free monogastric 
generation of Siphonophora (zool.}. 

eruciform (eroo'slform) a. [L. eruca, 
caterpillar ; forma, shape.] Hav- 
ing the shape of, or resembling a 
caterpillar ; appl. insect larvae 

erumpent (eriim'pent) a. [L. ex, out ; 
rumpere, to break.] Breaking out 
suddenly ; appl. fungal hyphae 

erythrin (grith'rin) n. [Gk. erythros, 
red.] A red colouring matter found 
in certain Algae (&?/.). 

erythrism (erith'rizm) n. [Gk. eryth- 
ros, red.] A condition due to ex- 
cessive amount of red colouring 
matter in the feathers (zool.}. 

erythroblasts (Srith'roblasts) n. plu. 
[Gk. erythros, red ; blastos, bud.] 
Amoeboid nucleated cells, derived 
from the mesoderm, which later 
contain haemoglobin and develop 
into red blood corpuscles (phys.}. 

erythrocyte (grtth'roslt) n. [Gk. eryth- 
ros, red ; kytos, hollow.] A red blood 
corpuscle (anat.}. 

erythrophilous (eVithrofllus) a. [Gk. 
erythros, red ; philein, to., love.] 
Having special affinity for red dyes ; 




appl. structures in a cell or to a 
type of cells (biol.}. 

erythrophyll (erith'rofil) n. [Gk. 
erythros, red ; phyllon, leaf.] A red 
colouring matter found in some 
leaves (bot.}. 

erythrozym (erith'rozlm) n. [Gk. 
erythros, red ; zyme, leaven.] One 
of the enzymes capable of acting 
upon the glucosides (bot.}. 

erythrozyme (grith'rozlm) n. [Gk. 
erythros, red ; zyme, leaven.] An 
enzyme capable of decomposing 
ruberythric acid (phys.}. 

escape (6skap') n. [M.E. escapen.] 
A plant originally cultivated, now 
found wild (bot.}. 

esculent (es'kulent) a. [L. esculentus, 
edible.] Suitable for food. 

escutcheon (esktich'un) n. [O.F. 
escuchon, shield.] The area on the 
rump of many quadrupeds which is 
either variously coloured or has the 
hair specially arranged ; the meso- 
scutellum of certain insects ; the 
ligamental area of certain bivalves 

eseptate (esep'tat) a. [L. ex, without ; 
septum, division.] Not supplied 
with septa (biol.}. 

esophagus (esof'agus), see oeso- 

esoteric (es'oter'fk) a. [Gk. esoterikos, 
arising within.] Arising within the 
organism (phys.}. 

espathate (espa'that) a. [L. ex, with- 
out ; spatha, sheath.] Having no 
spathe (hot.). 

esquamate (eskwa'mat) a. [L. ex, 
without ; squama, scale.] Having 
no scale (bot.}. 

estipulate (estip'ulat) a. [L. ex, with- 
out ; stipula, stem.] Having no 
stipules (bot.}. 

estivation (gs'tiva'shun), see aesti- 
vation (bot., zool.}. 

estuarine (es'tuarin) a. [L. aestus, 
swell of the sea.] Pert, or found 
in an estuary ; appl. plants and 
animals (biol.}. 

etaerio (ete'rlo) n. [Gk. efairia, an 
association.] A fruit composed of 
achenes or drupelets carried on an 
enlarged receptacle (bot.}. 

etheogenesis (6th'eoj5n'esTs) n. [Gk. 
etheos, youth ; gignesthai, to pro- 
duce.] A kind of parthenogenesis 

producing males, said to exist in 
some Protozoa (zool.\ 

Ethiopian (e'thto'pTan) n. [Gk. at- 
thiops, burned face.] A zoogeo- 
graphical region including Africa 
south of the Sahara and southern 
Arabia (zool.}. 

ethmoid (eth'moid) a. [Gk. ethmos, 
sieve ; eidos, shape.] Pert, bones 
which form a considerable part of 
the walls of the nasal cavity (anat.\ 

ethmoidal (ethmoi'dal) a. [Gk. 
ethmos, sieve ; et'dos, shape.] Pert. 
region of the ethmoids (anat.}. 

ethmoidal notch, a quadrilateral 
space separating the two orbital 
parts of the frontal (anat.}. 

ethmolysian (eth'molis'ian) a. [Gk. 
ethmos, sieve ; lyein, to loosen.] 
Pert, an apical system in which 
the madreporite extends backwards 
till it separates the two postero- 
lateral genitals (zool.}. 

ethmopalatine (eth'mopal'atin) a. 
[Gk. ethnics, sieve ; L. palatus, 
palate.] Found in the ethmo- 
palatine region, or stretching from 
the ethmoid to the palatine (zool.}. 

ethmophract (eth'mofrakt) a. [Gk. 
ethmos, sieve ; phrassetn, to fence 
in.] Pert, a simple, compact, apical 
system with the pores occurring 
only in the right anterior corner 

ethmoturbinals (eth'motur'binalz) . 
plu. [Gk. ethmos, sieve ; L. turbo, 
whorl.J Cartilages or bones in the 
cavity of the nostril which are folded 
so as to increase the olfactory area 

ethmovomerine (eth'movo'merin) a. 
[Gk. ethmos, sieve ; L. votner, 
ploughshare.] Pert, the ethmoid 
and vomer regions (zool.}. 

ethmovomerine cartilage, the plate 
of cartilage which forms the septum 
of the nose in the early stages of 
the embryo (emb.}. 

ethnology (ethnol'dji) . [Gk. ethnos, 
nation \logos, discourse.] Thescience 
which deals with the different races 
of mankind, their distribution, rela- 
tionship, and peculiarities (biol.}. 

ethology (ethol'qjl) . [Gk. ethos, 
custom ; logos, discourse.] Bio- 

etiolation (e'tiola'shun) n. [F. etioler, 




to blanch.] The condition pro- 
duced in plants reared in darkness 

etiolin (e'tiolin) n. [F. etioler, to 
blanch.] A yellowish pigment 
found in the chloroplasts of plants 
grown in darkness (phys.). 

etiology (e'tiol'oji), see aetiology. 

euaster (uas'ter) n. [Gk. eu, good ; 
aster, star.] An aster in which the 
rays meet at a common centre (zool.). 

eucephalous (ukgf'alus, -sef-) a. [Gk. 
eu, good ; kephale, head.] With 
well-developed head ; appl. certain 
insect larvae (zool.). 

eucone (ukon') a. [Gk. eu, good ; 
konos, cone.] Having the crystal- 
line cones fully developed in the 
single elements of the compound 
eye (zoo/.}. 

eudipleural (u'diploo'ral) a. [Gk. eu, 
good ; dis, double ; pleuron, side.] 
Symmetrical about a median plane ; 
bilaterally symmetrical (zool.). 

eudoxoxne (udok'som) n. [Gk. eu, 
well ; doxa, credit.] A monogastric 
free-swimming stage of a Siphono- 
phore in which there is no necto- 
calyx (zool.). 

eugenics (ujen'iks) ;/. [Gk. eu, well ; 
gcnos, birth.] The science dealing 
with the improvement of stock ; 
usually referred to betterment of 
human race (biol.). 

euglenoid (uglen'oid) a. [Gk. eu, well ; 
glene, pupil of eye.] Pert, or like 
Euglena ; appl. characteristic move- 
ment of Euglena (biol.). 

eumerism (u'me'rTzm) n. [Gk. eu, 
well ; meros, part.] An aggrega- 
tion of like parts (biol.). 

eumerogenesis (u'merojgn'gsis) . 
[Gk. eu, well ; meros, part ; gig- 
nesthai, to produce.] Segmentation 
in which the units are similar at 
least for a certain time (biol.). 

euplastic (uplas'tik) a. [Gk. eu, well ; 
plastos, moulded.] Readily organ- 
ized, easily forming a tissue (phys.). 

euryhaline (u'rihal'm) a. [Gk. eurys, 
broad ; halinos, marine.] Appl. 
marine animals adaptable to a wide 
range of salinity ; cf. stenohaline 

eurypylous (u'ripl'lus) a. [Gk. eurys, 
broad ; pyle, gate.] Wide at the 
opening ; appl. canal system of 

Sponges in which the chambers 
open directly into the excurrent 
canals by wide apopyles, and re- 
ceive the water from the incurrent 
canals through the prosopyles 

eusporangiate (u'sporan'jlat) a. [Gk. 
eu, well ; sporos, seed ; anggeion, 
vessel] Having the sporogenous 
tissue derived from the inner cell 
that follows the periclinal division 
of the superficial initial ; cf. lepto- 
sporangiate (bot.). 

Eustachian(usta'kian)<z. [It. Eustachi, 
Italian physician.] Pert, canal 
connecting tympanic cavity with 
pharynx (anat.). 

Eustachian valve, a rudimentary 
valve guarding the orifice of the 
inferior vena cava in the atrium of 
the heart (anat.). 

eustele (u'stel) n. [Gk. eu, well ; 
stele, pillar.] The arrangement of 
the vascular tissue into collateral 
bundles with the conjunctive tissue 
between, as in a typical Dicotyledon 

eustomatous (ustom'atus) a. [Gk. eu, 
well ; stoma, mouth.] Having a 
distinct mouth-like opening (zool.). 

euthenics (uthfin'lks) n. [Gk. euthen- 
ein, to thrive.] The science of the 
betterment of the human race on 
the side of intellect and morals ; 
the psychological as distinct from 
the physiological improvement, or 
eugenics (biol.). 

euthyneurous (u'thinu'rus) a. [Gk. 
euthus, straight ; neuron, nerve.] 
Having the visceral loop of the 
nervous system untwisted (zool.). 

evagination (e'vajina'shun) n. [L. e, 
out ; vagina, sheath.] The process 
of unsheathing, or product of this 
process ; an outgrowth (biol.). 

evanescent (ev'anes'gnt) a. [L. evan- 
escere, to vanish.] Disappearing 
early ; appl. flowers which fade 
quickly (bot.). 

eviscerate (evis'erat) v. [L. ex, out ; 
viscera, entrails.] To disembowel ; 
to eject the viscera, as Holothurians 
do on capture (zool.). 

evolute (e'volut) a. [L. evolvere, to 
unroll.] Turned back ; unfolded 

evolution (e'volu'shun) n. [L. evol- 




vere, to unroll.] The gradual de- 
velopment of organisms from pre- 
existing organisms (biol.). 

exalate (gksa'lat) a. [L. ex, without ; 
ala, wing.] Not having wing-like 
appendages (bot.). 

exalbuminous (gk'salbu'minus) a. [L. 
ex, without ; albumen, white of egg.] 
Without albumen ; appl. seeds with- 
out endosperm or perisperm, or 
both (dot.). 

exannulate (eksan'ulat) a. [L. ex, 
without ; annulus, ring.] Having 
a sporangium not furnished with 
an annulus or ring ; appl. certain 
ferns (bot.). 

exarch (ek'sark) n. [L. ex, without ; 
Gk. arche, beginning.] With the 
protoxylem strands in touch with 
the pericycle (dot.). 

exasperate (eksas'perat, egzas'perat) 
a. [L. ex, without ; asperare, to 
make rough.] Furnished with hard, 
stiff points (hot.). 

excentric (eksen'trik) a. [L. ex, 
without ; centrum, centre.] One- 
sided ; having the two portions of 
the lamina unequally developed 

exciple (gk'sipl) n. [L. excipula, re- 
ceptacles.] Theouter covering of the 
apothecium in certain Lichens (dot.). 

excitation (ek'sita'shun) n. [L. ex, 
out ; citare, to rouse.] The act of 
producing or increasing the stimu- 
lation ; the stimulation thus pro- 
duced (phys.). 

excitatory cells, motor cells in the 
sympathetic nervous system (phys.). 

excite (ekslt') v. [L. ex, out ; citare, 
to rouse.] To start or increase the 
vital activities of an organism or 
part thereof (phys.). 

excitonutrient (eksi'tonu'trient) a. 
[L. ex, out ; citare, to rouse ; 
nutriens, feeding.] Causing or in- 
creasing the nutrient activities 

exclusion (ekskloo'zhun) n. [L. ex- 
cludere, to exclude.] Act of expel- 
ling, or the product of the expulsion 

exconjugant (ekskon'joogant) n. [L. 
ex, out ; conjugare, to yoke.] An 
organism which is leading an inde- 
pendent life after conjugation with 
another (zool.). 

excreta (gkskre'ta) n. plu. [L. ex- 
cretum, separated.] Waste material 
eliminated from the body or any 
tissue thereof (phys.) ; deleterious 
substances formed within a plant 

excrete (ekskret') v. [L. ex, out ; 
cernere, to sift.] To eliminate waste 
material from the body (phys.) ; to 
withdraw useless materials from the 
place of most active metabolism in 
the plant (hot.). 

excretion (ekskre'shun) n. [L. ex, 
out ; cernere, to sift.] Act of elimi- 
nating waste material, or the pro- 
duct of the elimination (phys.). 

excurrent (ekskur'e'nt) a. [L. ex, 
out ; currere, to run.] Pert, ducts, 
channels, or canals in which there 
is an outgoing flow (zool.) ; with 
undivided main stem ; having the 
midrib projecting beyond the apex 

excurved (ekskurvd') a. [L. ex, out ; 
curvare, to curve.] Curved out- 
wards from the centre (zool.}. 

exfoliation (gksfo'lia'shun) n. [L. 
ex, out \folium, leaf.] The shedding 
of the leaves or scales from a bud 

exhalent (eksha'lfint) a. [L. ex, out ; 
halare, to breathe.] Capable of 
carrying from the interior outwards 

exindusiate (ek'slndu'zlat) a. [L. ex, 
out ; indusium, cover.] Having 
the sporangia uncovered or naked 

exine (ek'sm), see extine. 

exinguinal (eVsm'gwInal) a. [L. ex, 
out ; inguen, groin.] Occurring 
outside the groin ; pert, second 
joint of an arachnid leg (zool.). 

exites (ekslts') n. plu. [Gk. exo, 
without.] Offshoots on the outer 
lateral border of the axis of certain 
arthropod limbs (zool.}. 

exocardiac (ek'sokar'diak) a. [Gk. 
exo, without ; kardia, heart.] Situ- 
ated outside the heart (zool.). 

exocarp (ek'sokarp) n. [Gk. exo, 
without ; karpos, fruit.] The outer 
layer of the pericarp (bot.). 

exoccipital (ek'sokslp'ftal) a. [L. ex, 
without ; occiput, back of head.] 
Pert, a bone on each side of the 
foramen magnum (goal.). 




exochorion (Sk'sok5'rI5n) n. [Gk. 
exo, without ; chorion, chorion.] 
The outer layer of the membrane 
secreted by the follicular cells 
surrounding the egg in the ovary 
of Insects (zoo/.). 

exocoel (Sk'sosel) n. [Gk. exo, with- 
out ; koilos, hollow.] The space 
between the mesenteries of ad- 
jacent couples in certain Zoantharia 

exocoelar (eVsose'lar) a. [Gk. exo, 
without ; koilos, hollow.] Pert, the 
parietal wall of the coelom ; pert. 
space between adjacent couples 
of mesenteries in the Zoantharia 

exocoelom (eVsose'lom) n. [Gk. 
exo, without ; koilos, hollow.] The 
extra-embryonic body cavity of the 
embryo (emb.}. 

exoderm (eVsodgrm) n. [Gk. exo, 
without ; derma, skin.] The dermal 
layer of Sponges supposed by 
Haeckel to be equal to ectoderm 
of other animals (zoo/.). 

exodermis (eYsodeVmis) n. [Gk. 
exo, without ; L. dermis, skin.] 
See ectoderm. 

exogamete (Sk'sogamet') n. [Gk. 
exo, without ; gametes, mate.] A 
reproductive cell which fuses with 
one derived from another source 

exogamy (Sksog'amT) n. [Gk. exo, 
without ; gamos, marriage.] Con- 
jugation or fusion of isogametes 
with others of a different brood 

exogastrically (ek'sogas'trikal!) adv. 
[Gk. exo, without ; gaster, belly.] 
Where the shell is coiled towards 
the dorsal surface of the body 

exogenous (e'ksoj'e'nus) a. [Gk. exo, 
without ; genos, race.] Developed 
from superficial tissue, the super- 
ficial meristem (oof.) ; growing from 
parts which were previously ossified 

exognathion (6k'sognath'l8n) n. [Gk. 
exo, without ; gnathos, jaw.] The 
maxillary portion of the upper jaw ; 
the maxilla with exception of 
endognathion and mesognathion 

exoperidium (e'k'sope'rid'ium) n. 

[Gk. exo, without ; peridion, a 
small wallet.] The outer layer of 
the spore case in certain Fungi 

exoplasm (eVsoplazm) n. [Gk. 
exo, without ; plasma, something 
moulded.] The ectoplasm (biol.). 

exopodite (gksop'odit) n. [Gk. exo, 
without ; potts, foot.] The outer 
branch of a typical biramous 
crustacean limb (zool.}. 

exoskeleton (6k'sosk61'6ton) n. [Gk. 
exo, without ; skeletos, hard.] A 
hard supporting structure secreted 
by the ectoderm or by the skin 

exosmosis (gk'sosmo'sis) n. [Gk. 
exo, without ; osmos, impulse.] 
The passing out through a mem- 
brane of a gas or fluid, a phase in 
osmosis (phys.~). 

exospore (fik'sospor) n. [Gk. exo, 
without ; sporos, seed.] The outer 
coating of the sporangial wall ; one 
of the conidia (&?/.). 

exosporlum (ek'sospo'rmm) n. [Gk. 
exo, without ; sporos, seed.] The 
outer layer of the sporangial wall 

exostome (eVsostom) n. [Gk. exo, 
without ; stoma, mouth.] The 
opening or foramen in the outer 
wall of the ovule (bot.}. 

exostosis (eVs8sto's!s) n. [Gk. exo, 
without ; osteon, bone.] The forma- 
tion of knots on the surface of wood 
(oot.) -, the formation of knob-like 
outgrowths of bone at a damaged 
portion, or of dental tissue in a 
similar way (anaf.). 

exotheca (eYsothe'ka) n. [Gk. exo, 
without ; theke, box.] The extra- 
capsular tissue of a Coral (zoo/.). 

exothecal (gk'sothe'kal) a. [Gk. exo, 
without ; theke, box.] Pert, tissue 
outside the theca of a Coral (zoo/.), 

exothecate (eVsothe'kat) a. [Gk. 
exo, without ; theke, box.] Having 
an exotheca (zoo/.). 

exotic (gksot'ik, 6gz8t'Tk) a. [Gk. 
exotikos, foreign.] Signifying an 
introduced or non-endemic plant 

exotospore (Skso'tospor) n. [Gk. 
exotikos, foreign ; sporos, seed.] A 
sporozoite (zoo/.). 

exotropism (6ks6t'roplzm) n. [Gk. 




exo, without ; trepein, to turn.] The 
curvature away from the axis, ex- 
hibited by a laterally geotropic 
organ (bot.}. 

expiration (ek'spira'shun) n. [L. ex, 
out ; spirare, to breathe.] The act 
of emitting air from the lungs ; the 
act of emitting volatile substances 
from the lungs, or from any internal 
cavity (phys.}. 

exsculptate (ekskiilp'tat) a. [L. ex, 
out ; sculpere, to carve.] Having 
the surface marked with more or 
less regularly arranged raised lines 
with grooves between (sool.}. 

exscutellate (ek'skutel'at) a. [L. ex, 
without ; scutellum, shield.] Hav- 
ing no scutellum ; appl. Insects 

exserted (ekseYted) a. [L. exserere, 
to stretch out.] Protruding ; appl. 
stamens which project beyond the 
corolla (bot.} ; protruding beyond 
some including organ or part 

exsertile (eksgr'til) a. [L. exserere, 
to stretch out.] Capable of extru- 
sion (biol.}. 

exsufflation (eks'sufla'shun) n. [L. 
ex, out ; sufflare, to blow.] Forced 
expiration from the lungs (phys.}. 

extend (Skstfind') v. [L. ex, out ; 
tendere, to stretch.] To straighten 
out, as opp. to flex or bend any 
organ (phys.}. 

extension (elcstgn'shiin) n. [L. ex, 
out; tendere, to stretch.] Straighten- 
ing out of an organ (phys.}. 

extensor (ekstgn'sor) n. [L. ex, out ; 
tendere, to stretch.] Any muscle 
which extends a limb or part there- 
of (anat.). 

exterior (gkste'rior) a. [L. externus, 
on the outside.] Situated on the 
side away from the axis or definitive 
plane (biol.}. 

external (gkster'nal) a. [L. externus, 
outside.] Near the outside, away 
from the mesial plane (anat.}. 

extine (ek'stin) n. [L. exter, on the 
outside.] The outer coat of the 
pollen grain (bot.}. 

extra-axillary (eVstra-aksTl'arl) a. [L. 
exter, outside ; axilla, armpit.] 
Arising above the axil of a leaf, 
said of branches which develop 
from the upper bud when there 

are more than one in connection 
with the axil (bot.}. 

extrabranchial (ek'strabrang'kfal) a. 
[L. exter, outside ; Gk. brangchia, 
gills.] Arising outside the branchial 
arches (zoo!.}. 

extracapsular (Sk'strakap'sular) a. 
[L. exter, outside ; capsida, cup.] 
Arising or situated outside the 
capsule; appl. ligaments, etc., in 
connection with a joint (anat.} ; 
appl. protoplasm lying outside the 
central capsule in some Protozoa 

extracellular (ek'straseTular) a. [L. 
exter, outside ; cellula, little cell.] 
Occurring outside the cell (biol.}. 

extraembryonic (eVstraem'brion'ik) 
a. [L. exter, outside ; Gk. embryon, 
foetus.] Situated outside the em- 
bryo proper (emb.}. 

extraenteric (ek'straenter'ik) a. [L. 
exter, outside ; Gk. enteron, gut.] 
Outside the alimentary tract 

extrafloral (ek'straflo'ral) a. [L. 
exter, outside ; flos, flower.] Situ- 
ated outside the flower (bot.}. 

extranuclear (ek'stranu'klear) a. [L. 
exter, outside ; nucleus, nucleus.] 
Pert, structures or forces acting 
outside the nucleus ; situated out- 
side the nucleus (biol.}. 

extraocular (ek'straok'ular) a. [L. 
exter, outside ; cculus, eye.] Ex- 
terior to the eye ; appl. antennae 
of Insects (zool.}. 

extrastapedial (ek'strastape'dlal) a. 
[L. exter, outside ; stapes, stirrup.] 
Extending beyond the stapedio- 
columellar junction (anat.}. 

extrastelar (6k'straste'lar) a. [L. 
exter, outside ; Gk. stele, column.] 
Pert, ground tissue outside the 
vascular tissue (bot.}. 

extravaginal (ek'stravaj'inal) a. [L. 
exter, outside ; vagina, sheath.] 
Forcing their way through the 
sheath, as the shoots of many 
plants (bot.}. 

extravasate (ekstrav'asat) v. [L. 
exter, outside ; vas, vessel.] To 
force its way from the proper 
channel into the surrounding tissue; 
said of blood, etc. (phys.}. 

extraventricular (gk'strdvgntrik'ular) 
a. [L. exter, outside ; -venter, 




belly.] Situated or arising beyond 
the ventricle (phys.). 

extremity (e'kstre'm'iti) n. [L. ex- 
tremitas, limit.] The limb, or 
distal portion of a limb ; or the 
distal end of any limb-like structure 
(biol., anat.). 

extrinsic (gkstrin'sik) a. [L. ex- 
frinsecus, on the outside.] Pert. 
muscles not wholly within the part 

extrorse (Skstrors') a. [L. extrorsus, 
outwardly.] Turned away from the 
axis (hot.}. 

exudation (ek'suda'shun) n. [L. 
exudere, to sweat.] Any discharge 
through an incision or pore, e.g. 
gums, resins, moisture, etc. (biol.). 

exumbral (gksiim'bral) a. [L. ex; 
out ; umbra, shade.] Pert, the 
rounded or convex upper surface 
of a jelly-fish (zoo/.). 

exumbrella (ek'sumbreTa) n. [L. ex, 
out ; umbra, shade.] The upper 
rounded or convex surface of a 
jelly-fish (goal.). 

exuviae (egzu'vle) n.plu. [L. exuere, 
to pull off.] Cast-off skins, etc., 
of animals (zoo/.). 

eye (I) n. [M.E. ighe^\ The organ 
of sight or vision ; one of the 
pigment spots in various animals 
and in many of the lower plants 
(biol.) ; the bud of a tuber (dot.). 

eye-ball, the globular capsule of the 
vertebrate eye ; also the capsule 
and its contents. 

eye spots, certain pigment spots in 
many of the lower plants and 
animals, and also in some verte- 
brates, which are supposed to have 
an ocular function (biol.). 

P!, us^d for convenience to denote the 
first filial generation, or the hybrids 
arising from a first cross, successive 
generations arising from this one 
being denoted by F^ F 3 , etc. P t 
denotes the parents of the F t 
generation, P 2 the grandparents, 
and so on (biol.}. 

fabella (fabel'a) n. [L. fat>e//<i t small 

bean.] A small fibro-cartilage 
ossified in the gastrocnemius (anaf.). 

fabiform (fa'blform) a. [L.faba, bean ; 
forma, shape.] Bean-shaped. 

Pabrician system, a classification of 
thearthropoda based on the anatomy 
of the mouth parts (zoo/.). 

facet (fas'et) n. [L. fades, face.] A 
smooth, flat, or rounded surface for 
articulation (anat.) ; an ocellus 

facial (fa'shal) a. [L. fades, face.] 
Pert, face; appl. artery, nerve, bone, 
vein, etc. (anaf.). 

faciolingual (fa'shloling'gwal) a. [L. 
fades, face ; lingua, tongue.] Pert. 
or affecting the face and tongue 

facultative (fak'ulta'tiv) a. [L.facu/tas, 
faculty.] Having the power of 
living under different conditions 

facultative parasites, parasites 
which may be normally self-depend- 
ent, but which are adaptable to 
parasitic or semiparasitic mode of 
life ; cf. obligatory parasites (biol.). 

faeces (fe'sez) n. plu. [L. faeces, dregs.] 
The excrement or waste matter from 
the bowels (anaf.). 

falcate (fal'kat) a. [L. falx, sickle.] 
Sickle-shaped ; hooked (biol.). 

falciform (fal'slform) a. [L. falx, 
sickle ; forma, shape.] Sickle- 
shaped or scythe-shaped (anaf., 

falciform ligament, a dorso-ventral 
fold of the peritoneum, attached to 
under surface of diaphragm and 
the anterior and upper surfaces of 
the liver (anaf.). 

falcula (lal'kula) n. [L.falcula, little 
hook.] A curved scythe-like claw 

falculate (fal'kulat) a. [L. falcula, 
little hook.] Curved, and sharp at 
the point. 

Fallopian tubes (falo'pian), the upper 
portions of the oviduct in man and 
mammals ; the anterior portions of 
the Miillerian ducts (anaf.). 

false ribs, -those ribs whose carti- 
laginous ventral ends do not join 
the sternum directly, if at all (anaf.). 

falx (falks) n., falces (fal'sez) plu. 
[L. fair, sickle.] A sickle-shaped 
fold of the dura mater (ana/.). 




family (fam'ili) n. [L.famih'a, house- 
hold.] Term used in classification, 
signifying one group of an Order 

fan (fan) n. [A.S./a#,fan.] A bird's 
tail feathers (zool.}. 

fang (fang) n. [A.S. fang, grip.] A 
long-pointed tooth, especially the 
poison tooth of snakes (zool.) ; the 
root of a tooth (anat.). 

faradisation (far'adiza.'shun) n. [Fara- 
day, electrician.] Method of stimu- 
lation inducing partial or complete 
tetanus (phys.). 

farina (fare'na, fari'na) n, [L. farina, 
flour.] The pollen of plants (bot.) ; 
the fine mealy-like powder found 
on some insects (zool.). 

farinaceous (far'ina'shus) a. [L. 
farina, flour.] Covered with fine 
mealy-like dust (zool.). 

farinose (far'inos) a. {L. farina, flour.] 
Covered with fine powder or dust 
(bot., zool.). 

fascia (fas'ia, fash'ia) n. [L. fascia, 
band.] An ensheathing band of 
connective tissue (anat.). 

fascial (faYial, fash'ial) a. [L. fascia, 
bundle.] Pert, a fascia, ensheathing 
and binding (anat.). 

fasciated (fas'ia'ted, fash'ia'tgd) a. [L. 
fascia, bundle.] Banded (zool.} ; 
arranged in fascicles ; appl. stems 
or branches malformed and flattened 

fascicle (fas'ikl) n. [L. fasciculus, 
dim. of fascia, bundle.] A small 
bundle or tuft, as of fibres (ana/.) 
or of leaves (bot.). 

fascicular (fasik'ular) a. [L. fascicu- 
lus, dim. of fascia, bundle.] Pert. 
a fascicle ; arranged in bundles or 
tufts ; appl. cambium, tissue (bot.). 

fasciculus (fasik'ulus) n. {L. fascicu- 
lus, little bundle.] A fascicle ; the 
direct pyramidal tract (anat.). 

fasciola (fasl'ola) n. [L. fasciola, a 
small bandage.] A narrow colour 
band (zool.} ; a delicate lamina con- 
tinuous with the dentate gyrus 

fascicle (fas'iol) n. [L. fasciola, a 
small bandage.] A ciliated band 
on certain Echinoids for sweeping 
fresh water over the surrounding 
parts (zool.}. 

fastigiate (fastij'iat) a. [L. fastigare. 

to slope up.] With branches parallel 
and erect (hot.} ; in pyramidal or 
conical form (zool.}. 

fat (fat) n. [A.S.faett, fat.] Adipose 
tissue ; any part of animal tissue 
which has its cells filled with a 
greasy or oily reserve material 

fatigue (fateg') n. [L. fatigare, to 
weary.] The effect produced by 
long stimulation on the cells of an 
orga"n (phys.). 

fauces (fosez) n. plu. [L. fauces, 
throat.] The upper or anterior part 
of the throat between palate and 
pharynx (anat.} ; the mouth of a 
spirally coiled shell (zool.}. ; the 
throat of a corolla (dot.}. 

fauna (fon'a) n. {L.faunus, a god of 
the woods.] All the animals 
peculiar to a country, area, or period 

faunal region, an area characterized 
by a special group or groups of 
animals (zool.}. 

favella (favgl'a) n. [L. favus, honey- 
comb.] A conceptacle of certain 
red Algae (bot.}._ 

faveolate (fave'olat) a. [L. faveolus, 
dim. of 'favus, honeycomb.] Honey- 
combed or alveolate. 

faveolus (fave'6'lus) n. [L. faveolus, 
small honeycomb.] A small de- 
pression or pit ; alveola (hot.}. 

favose (favos') a. [L. favus, honey- 
comb.] Like a honeycomb ; alveo- 
late (dot.). 

feather-veined, appl. leaf in which 
the veins run out from the mid-rib 
in a regular series at an acute angle 

feces, see faeces. 

fecundity (fekun'diti) n. [L.fecundus, 
fertile.] Power of a species to 
multiply rapidly (biol.}. 

female (fe'mal) n. [L.femina, woman.] 
A pistillate flower (bot.) ; a female 
animal, i.e. an egg-producing or 
young- producing animal (zool.) 
symbol %. 

female pronucleus, the nucleus left 
in the ovum after maturation. 

femoral (fgm'oral) a. [L. femur, 
thigh.] Pert, the thigh; appl. artery, 
vein, nerve, etc. ; crural (zool}. 

femur (fe'mur) n. {L. femur, thigh.] 
The proximal bone of the hind 




limb in man and vertebrates (anat.}; 
the third joint in an insect's leg 
counting from the proximal end 

fenchone (fSn'chon) n. [Ger./enc/ie/, 
fennel.] A ketone, the essential 
oil in oil of fennel (phys.}. 

fenestra (fgneYtrS) n. [L. fenestra, 
window.] An opening in a bone, 
or between two bones (anat.} ; a 
pit on the head of the cockroach ; 
a transparent spot on the wings 
of insects (zool.}. 

fenestrate (fgngs'trat) a. [L. fenestra, 
window.] Having small perfora- 
tions or transparent spots, appl. 
insects' wings (zool.} ; having 
numerous perforations, appl. leaves 

fenestrule (ffineVtrool) n. [L.. fenestra, 
window.] A small opening be- 
tween the branches of a polyzoan 
colony (zool.}. 

feral (f e'ral) a. [L. fera, wild animal.] 
Wild, or escaped from cultivation 
and reverted back to the wild state 

ferment (feYmSnt) n. [L. fermentum, 
ferment.] A substance, organized 
or unorganized, capable of produc- 
ing fermentation (phys.}. 

fermentation (feYmSnta'shun) n. [L. 
fermentum, ferment.] Any of the 
transformations occurring in or- 
ganic substances caused by the 
presence of a ferment (phys.}. 

ferruginous (fgroo'jmus) a. [L.ferru- 
ginus, rusty.] Having the appear- 
ance of a rusty spot (bot.}. 

fertile (feVtil) a. [L.fertilis, fertile.] 
Capable of producing ; of eggs or 
seeds capable of developing (biol.}. 

fertilization (feYtiliza'shun) n. [L. 
fertilis, fertile.] The orderly and 
intimate union of male and female 
pronuclei (biol.} ; the process of 
pollination (bot.}. 

fetlock (feY16k) n. [I eel. fet, step ; 
lokka, tuft of hair.] The tuft of 
hair behind a horse's pastern joint ; 
the pastern joint itself (zool.}. 

fibre (ffber) n. [L. fibra, band.] A 
strand of nerve, muscle, connective, 
or bast-tissue (bot., zool.}. 

fibril (fl'brll) n. [L. fibrilla, a small 
fibre.] A small thread-like structure 
or fibre, a component part of a 

fibre (anat.}; a root-hair ; a slender 
filiform outgrowth on some Lichens 

fibrillae (flbril'e) n. plu. [L. fibrilla, 
small fibre.] The thread-like 
branches of roots (bot.} ; minute 
elastic fibres secreted within spongin 
cells ; minute muscle-like threads 
found in various Infusorians (zool.). 

fibrillate (fl'brilat) a. [L. fibrilla. 
small fibre.] Having fibrillae or 
hair-like structures (bot.}. 

fibrillose (fl'brilos, fibril'os) a. [L. 
fibrilla, small fibre.] Furnished 
with fibrils ; appl. mycelia of 
certain Fungi (bot.}. 

fibrin (ffbrin) n. [L. fibra, band.] 
An insoluble proteid found in blood 
after coagulation, it is readily 
digested in gastric juice (p/tys.}. 

fibrinogen (fibrin'qje'n) n. [L. fibra, 
band ; Gk. gignesthai, to produce.] 
A soluble constituent of blood which 
yields fibrin and produces coagula- 
tion (phys.}. 

fibro-cartilage (fi'bro-kar'tilaj) n. [L. 
fibra, band ; cartilago, gristle.] A 
kind of cartilage whose matrix is 
mainly composed of fibres similar 
to connective tissue fibres, found 
at articulations, cavity margins, and 
osseous grooves (anat }. 

fibrous (fi'brus) a. [L fibra, band.] 
Composed of fibres ; appl. tissue 
(anat.} ; roots (bot.}. 

fibula (fib'ula) n. [L. fibula, buckle.] 
The outer and smaller bone of 
the shin (anat.}. 

fibulare (fib'ula're, -ara) n. [L. fibula, 
buckle.]/ The outer element of the 
proximal row of the tarsus (anat.}. 

filament (firSme'nt) n. [L. filuni, 
thread.] The stalk of the anther 
(bot.} ; the stalk of a down-feather 

fllicauline (fil'ikolTn) a. [L. filum, 
thread ; caulis, stalk.] With a 
thread-like stem (bot., zool.}. 

filiciform (fills'iform) a. [L. filix, 
fern ; forma, shape.] Shaped like 
the frond of a fern (bot.}. 

fllicoid (fil'Ikoid) a. [L. filix, fern; 
Gk. eidos, like.] Shaped like or 
resembling a fern (bot.}. 

filiform (ffliform) a. [L. filum, 
thread ; forma, shape.] Thread- 




flliform papillae, papillae on the 
tongue ending in numerous minute 
slender processes (anat.}. 

flligerous (filij'eriis) a. [L. filum, 
thread ; gerere, to carry.] With 
thread-like outgrowths or flagella 

fillet (fil'et) n. [L. filum, thread.] 
Band of white matter in the brain ; 
the lemniscus of the mid-brain 

flloplume (fil'oploom) n. [L. filum, 
thread ; pluma, feather.] A deli- 
cate hair-like feather with long 
axis and a few free barbs at the 
apex (zool.}. 

filopodia (fil'opo'dia) n. plu. [L. 
filum, thread ; Gk. pous, foot.] 
Thread-like pseudopodia of Proto- 
zoa (zool.}. 

filose (fi'los) a. [L. filum, thread.] 
Slender ; threadlike ; appl. pseudo- 
podia of Protozoa (zool.}. 

filtration (filtra'shun) n. [F. filtrer, 
to strain.] Appl. the iridial angle 
of the cornea (anat.} ; straining, as 
of lymph through capillary walls 

filum terminate, the terminal 
thread, a slender grey filament, of 
the spinal cord (anat.}. 

fimbria (fim'bria) ;/., fimbriae (fim'- 
brie) plu. [L. fimbria, fringe.] 
Any fringe-like structure (anat., 
bot.} ; a prolongation of the hippo- 
campus (anat.} ; delicate processes 
fringing the mouth of tubes or 
ducts, as of the oviduct ; or the 
siphons of molluscs (zool.}. 

flmbriated (fim'bria'tecl) a. [L. fim- 
bria, fringe.] Fringed at the 
margin, as petals (bot.}, as tubes 
or ducts (zool.}. 

fin (fin) n. [A.S. finn, fin.] A fold 
of skin with fin-rays and skeletal 
supports, corresponding in the case 
of the paired fins to limbs, found 
in most fishes (zool.}. 

flnials (fin'Talz) n. plu. [L. finis, 
end.] The ossicles of the distal 
rami of Crinoids which do not 
branch again (zool.}. 

fin-rays, horny supports of the fins 

fissilingual (fis'Iling'gwal) a. [L. 
fissus, cleft ; lingua, tongue.] With 
bifid tongue (zool.}. 

fission (fish'iin) n. [L. fissus, cleft.] 
Cleavage of cells ; division of a 
unicellular organism into two or 
more parts, thereby reproducing 
its kind (biol.}. 

fissiparous (fisip'ariis) a. [L. fissus, 
cleft ; parere, to beget.] Repro- 
ducing by binary or multiple fission 

fissiped (f is'ipgd) n. [L. fissus, cleft ; 
pes, foot.] With cleft feet, that is, 
with digits of feet separated (zool.}. 

fissirostral (fis'iros'tral) a. [L. fissus, 
cleft; rostrum, beak.] With deeply- 
cleft beak (zool.}. 

fissure (flsh'ur) n. [L. fissus, cleft.] 
A cleft, deep groove, or furrow 
dividing an organ into lobes, or 
sub-dividing and separating certain 
areas of the lobes (anat.}. 

fix (fiks) v. {, fixed.] To kill, 
and preserve ; to establish (biol.}. 

fixation muscles, muscles which 
prevent disturbance of the equi- 
librium of the body generally, and 
fix limbs in the case of limb-move- 
ments (anat.}. 

flabellate (flabel'at) a. [L. flabellare, 
to fan.] Fan-shaped. 

flabellate antennae, pectinate an- 
tennae with long processes (zool.}. 

flabelliform (flabel'Iform) a. [L. 
flabellum, dim. of flabrum, breeze ; 
forma, shape.] Fan-shaped. 

flabellinerved (fiabel'Tnervd) a. [L. 
flabellum, little breeze ; nervus, 
sinew.] Appl. leaves with many 
radiating nerves (bot.}. 

flabellum (flabel'um) n. [L. flabellum, 
fan.] Any fan-shaped organ or 
structure ; the distal exite of a 
branchiopodan limb ; the epipodite 
of certain crustacean limbs (zool.}. 

flagellate (flaj'glat) a. [L. flagellum, 
whip.] Furnished with flagella ; 
like a flagellum (bot., zool.}. 

flagelliform (flajel'Tform) a. [L. 
flagellum, whip ; forma, shape.] 
Lash-like ; like a flagellum (bot., 

flagellula (flaj el'ula) n. [L. flagellula, 
dim. of flagellum, whip.] A flagel- 
late zoospore (zool.}. 

flagellum (flajeTum) n. [L. flagellum, 
whip.] The lash-like process of 
many Protista ; a long slender 
runner or creeping stem (bot.}. 




flame cells, the terminal cells of 
the branches of the excretory 
system in many worms, with cavity 
continuous with the lumen of the 
duct, and containing a cilium or 
bunch of cilia, the motions of which 
give a flickering appearance similar 
to that of a flame ; a pronephri- 
diostome (zool.). 

flavescent (flaves'ent) a. [L. fla-u- 
escere, to turn yellow.] Growing 

flex (flgks) v. [L. flectere, to bend.] 
To bend ; appl. movement of limbs 

flexor (flek'sor) n. [L. flexus, bent.] 
A muscle which bends a limb (or 
part) by its contraction (anat.). 

flexuous (flek'suus) a. [L. flexus, 
bent.] Curving in a zig-zag 
manner (bot.). 

flexure (fleVsur) n. \L. flexus, bent.] 
A curve or bend ; appl. the curve 
in the embryonic brain, the curve 
of the intestine (anaf.). 

float (flot) n. [A.S.fota, ship.] The 
pneumatophore of Siphonophores 
(zool.) ; a large spongy mass serving 
as a float in some Pteridophytes 

floating ribs, ribs not uniting at 
their ventral end with the sternum 

floccose (flok'os) a. [L. floccus, a lock 
of wool.] Covered with wool-like 

floccular (flok'ular) a. [L. floccus, 
lock of wool.] Pert, the flocculus 

flocculence (flok'ulens) n. [L. floccus, 
lock of wool.] Adhesion in small 
flakes, as of a precipitant (phys.). 

flocculent (flok'Qlgnt) a. [L. floccus, 
lock of wool.] Covered with a soft 
waxy substance giving the appear- 
ance of wool (zool.) ; covered with 
small woolly tufts (bot.). 

flocculus (flok'ulus) n. [L. floccus, 
lock of wool.] A small accessory 
lobe on each lateral lobe of the 
cerebellum (anaf.). 

floccus (flok'us) n. {L. floccus, lock of 
wool.] The tuft of hair terminating 
a tail ; the downy plumage of young 
birds (zool.) ; a mass of hyphal 
filaments in Algae and Fungi 

flora (flo'r5) n. [L. flos, flower.] 
The plants peculiar to a country, 
area, or period (bot.). 
floral (flo'ral) a. [L. flos, flower.] 
Pert, the flora of a country or area ; 
pert, flowers (bot.). 

florescence (floreVe'ns) n. [L. flos, 
flower.] Bursting into bloom (bot.). 
floret (flor'et) n. [L. flos, flower.] 
One of the small individual flowers 
of a composite flower (bot.). 
fioricoxne (flor'ikom) n. [L. flos, 
flower ; coma, hair.] A form of 
branched hexaster spicule (zool.). 
floscelle (floseT) n. [L. flosculus, a 
little flower.] The flower-like struc- 
ture in some Echinoids round the 
mouth composed of the five bour- 
relets and the five phyllodes (zool.). 
floss (flos) n. [F. floche, soft.] A 
downy or silky substance (bot.) ; the 
loose pieces of silk in a cocoon 

flower (flow'er) n. [L. flos, flower.] 
The blossom of a plant, comprising 
generally sepals, petals, stamens, 
and pistils ; a leafy shoot adapted 
for reproductive purposes (bot.). 
fluvlatile (floo'vlatil) a. [L.fluviatilis, 
pert, river.] Growing in or near 
streams (hot.) ; inhabiting and de- 
veloping in streams, appl. certain 
insect larvae (zool.). 
fluviomarine (floo'viomaren') a. [L. 
fluvius, stream ; mare, the sea.] 
Found in rivers and in the sea 
(zool.) ; pert, rivers and the sea 
(bot., zool.). 

fluvioterrestrial (floo'viotgreYtrial) a. 
[L. fluvius, stream ; terra, land.] 
Found in streams and in the land 
beside them (zool.). 
flux (fluks) n. [L. fluere, to flow.] 
Term appl. species that are not yet 
stable (btol.). 

foetal (fe'tal) a. [L. foetus, offspring.] 
Embryonic ; pert, a foetus (emb.). 
foetid glands, small sac-like glands 
in Orthoptera which secret* an 
ill-smelling fluid (zool.). 
foetus (fe'tus) n. [L. foetus, offspring.] 
An embryo in the egg or in the 
uterus (emb.). 

foliaceous (fo'lla'shus) a. [L. folium, 
leaf.] Having the form or texture 
of a foliage leaf (bot.) ; thin ; leaf- 
like (zool.). 




follar (fo'liar) a. [L. folium, leaf.] 
Pert, or consisting of leaves (bot.}. 

foliobranchiate (fo'liobrang'kiat) a. 
[L. folium, leaf; Gk. brangchia, 
gills.] Possessing leaf-like gills 

foliolae (fo'liole) n. plu. [L. folium, 
leaf.] Leaf-like appendages of the 
telum (zool.}. 

foliolate (fo'liolat) a. [L. folium, 
leaf.] Pert, leaflets (&?/.) 

foliole (fo'liol) n. [L. folium, leaf.] 
Small leaf-like organ or appendage 
(zool.} ; a leaflet (&>/.). 

foliose (fo'lios) a. [L. folium, leaf.] 
With many leaves (&?/.). 

folium (fo'lium) n. [L. folium, leaf.] 
A flattened plate-like structure in 
the cerebellum (anat.}. 

follicle (fol'ikl) n. [L.folliculus, small 
sac.] A capsular fruit which opens 
on one side only (bot.} ; a cavity or 
sheath (zool.}. 

follicular (f olik'ular) a. [L.folliculus, 
a small sac.] Pert., like or con- 
sisting of follicles. 

folliculate (folik'ulat), follicular. 

folliculose (folik'ulos) a. [L.folliculus, 
a small bag.] Having follicles (bot.}. 

fontanelle (fon'tangl') n. [F./ontan- 
elle, a little fountain.] A gap or 
space between bones in the cranium 
closed only by membrane (anat.}. 

fonticulus (fontik'ulus) n. [L. fonti- 
culus, dim. of fans, fountain.] The 
depression at the anterior end of 
the sternum (anat.}. 

food-vacuole, a small vacuole con- 
taining fluid and small food- 
particles, contained in the endosarc 
of many Protista. 

foot (foot) n. [A.S. fot, foot.] An 
embryonic structure in ferns through 
which nourishment is obtained 
from the prothallus ; the basal 
portion of the sporophyte in Mosses 
(bot.} ; an organ of locomotion, 
differing widely in different animals, 
from the tube-foot of Echinoderms, 
the muscular foot of Gastropods and 
Molluscs, the tarsus of Insects, to 
the foot of vertebrates and man 

foramen (fora'mfin) n. [L. foramen, 
an opening.] The opening through 
the coats of the ovule (bot.} ; any 
small perforation (anat.}. 

foramen magnum, the opening in 
the occipital region of the skull 
through which the spinal cord 
passes (anat., zool.}. 

foraminate (foram'fnat) a. [L. fora- 
men, opening.] Pitted ; having 
many foramina (zool.}. 

foraminiferous (foram'inif'erus) a. 
[L. foramen, opening ; ferre, to 
carry.] Containing shells of the 
Foraminifera (zool.}. 

forceps (for'sSps) n. [L. forceps, a 
pair of tongs.] The clasper-shaped 
anal cerci of some Insects ; the 
large fighting or seizing claws of 
crabs and lobsters (zool.}. 

forcipated (for'slpated) a. [L. forceps, 
pair of tongs.] Resembling forceps, 
or forked like a forceps (zool.}. 

forcipulate (forsip'ulat) a. [L. forceps, 
pair of tongs.] Sharped like a small 
forceps ; appl. asteroid pedicellariae 

forfex (forfgks') n. [L. forfex, pair 
of shears.] A pair of anal organs 
which open and shut transversely, 
occurring in certain Insects (zool.}. 

forficate (for'flkat) a. [L. forfex, 
shears.] Deeply notched (zool.}. 

formation (forma'shun) n. [L. forma, 
shape.] Structure arising from an 
accumulation of deposits (pal.}. 

formative (for'mativ) a. [L. forma, 
shape.] Appl. matter which is 
living and developable (phys.}. 

fornicated (for'mka'te'd) a. [L.fornix, 
vault.] Concave within, convex 
without ; arched (zool.}. 

fornix (for'niks) n. [L.fornix, vault.] 
An arched sheet of white longi- 
tudinal fibres beneath the corpus 
callosum (anat.} ; one of the arched 
scales in the orifice of some flowers 

fossa (fos'a) ;/. [L. fossa, ditch.] A 
ditch or trench-like depression 

fossette (f6s6t') n. [L. fossa, ditch.] 
A small pit ; a socket containing 
the base of the antennule in Arthro- 
pods (zool.}. 

fossil (fos'il) n. [L. fossilis, dug up.] 
Petrified animal or plant, or portion 
thereof, found in rocks (biol.}. 
fossiliferous (fos'ilif'erus) a. [L. 
fossilis, dug up ; ferre, to carry.] 
Containing fossils (biol.}. 




fossorial (foso'rial; n. [L. fossor, 
digger.] Adapted for digging ; 
appl. claws, feet (zool.}. 

fossula (fos'ula) n. [L. fossa, ditch.] 
A small pit with reduced septa on 
one side of a corallite cup in the 
Rugosa (pal.}. 

fossulate (fos'ulat) a. \L. fossa, ditch.] 
With slight hollows or grooves 

fossulet (fos'ulet) ;/. [ ssa, ditch.] 
A long narrow depression (zool.}. 

fovea (fo'vea) n. [L. fovea, depres- 
sion.] A small pit or fossa (anat.} ; 
a small hollow at the leaf base in 
Isoetes containing a sporangium 

foveate (fo'veat) a. [L. fovea, de- 
pression.] Pitted. 

foveola (fove'ola) n. [L.foveola, small 
pit.] A small pit ; a shallow cavity 
in bone (anat.} ; a small depression 
just above the fovea in the leaf of 
Isoetes (bot.}. 

foveolate (fo'veolat) a. [L. foveola, 
small pit.] Having regular small 
depressions (hot., zool.}. 

fragmentation (frag'me'nta'shun) n. 
[L. frangere, to break.] Division 
into small portions (biol.} ; nuclear 
division by simple splitting (biol.}. 

free (fre) a. [A.S. freo, acting at 
pleasure.] Motile ; unattached ; 
distinct ; separate. 

frenate (fre'nat) a. [L./renum, bridle.] 
Having a frenum or frenulum (zool.}. 

frenulum (frgn'ulum) ., frenula 
(frfin'ula) plu. [L. frenulum, dim. 
of frenum, bridle.] A fold of mem- 
brane, as of tongue, clitoris, etc. 
(anat.} ; a process on the hind- wing 
of Lepidoptera for attachment to 
fore-wing ; a thickening of the sub- 
umbrella of certain Scyphomedusae 

frenum (fre'num) ., frena (fre'na) 
plu. [L. frenum, bridle.] A fren- 
ulum ; a fold of integument at 
junction of mantle and body of 
Cirripedes, ovigerous in Peduncu- 
lata (zool.}. 

frond (fr6nd) n. [L. frons, leafy 
branch.] A leaf, especially of a 
fern (dot.). 

frondescence (frondSs'e'ns) n. [L. 
frondescere, to put forth leaves.] 
Development of leaves (tot.}. 

frons (fronz) n. [L. frons, forehead.] 
The forehead. 

frontal (frun'tal) a. [L. frons, fore- 
head.] In the region of the fore- 
head ; appl. artery, vein, lobe, con- 
volution, etc. (anat.} ; appl. head- 
organ of Nemertines ; a prostomial 
ridge of Polychaetes ; palps of 
certain Nereids (zool.}. 

frontocerebellar fibres, fibres pass- 
ing from the frontal region to the 
cerebellum (phys.}. 

fronto-ethmoidal (frun'to-e'thmoid'al) 
a. Pert, the frontal and ethmoidal 
bones ; appl. suture (an<it.}. 

frontonasal (frun'tona'zji 1) a. [L. 
frons, forehead ; nasum, nose.] 
Pert, forehead or frontal region 
and the nose ; appl. ducts and pro- 
cesses (emo.}. 

frontonasal ducts, ducts connecting 
the nasal cavities with .the frontal 
sinuses (anat.}. 

frontosphenoidal (frun'tosfenoid'al) a. 
[L. frons, forehead; Gk. sphen, 
wedge.] Pert, frontal and sphenoid 
bones ; appl. a process of the zygo- 
matic articulating with the frontal 

fructification (fruk'tiflka'shiin) n. [L. 
fructus, fruit ; facere, to make.] 
Fruit formation (bot.}. 

frugivorous (froojiv'orus) a. \L./rux, 
fruit ; vorare, to devour.] Fruit- 
eating ; appl. certain animals (zool.}. 

fruit (froot) n. [F. fruit, from L. 
fructus, fruit.] The fertilized and 
developed ovary of a plant (bot.}. 

frustule (frus'tul) n. [L. frustulum, 
a small fragment.] The proto- 
plasmic cell of a diatom (bot.}. 

frutescent (froot6s'6nt) a. [L.frutex, 
shrub.] Shrub-like (bot.}. 

frutex (froo'tSks) n. [L. frutex, 
shrub.] Shrub (bot.}. 

fruticose (froo'tikos) a. [L. frutex^ 
shrub.] Shrub-like (bot.}. 

fruticulose (frootik'ulos) a. [L.frutex, 
shrub.] Like a small shrub (bo). 

fucivorous (fusiv'orus) a. [L. fucus, 
rock-lichen ; vorare, to devour.] 
Eating seaweed ; appl. certain 
animals (zool.}. 

fucoid (fu'koid) a. [L. fucus, rock- 
lichen.] Pert, or resembling sea- 
weed (bot.}. 

fugacious (fuga'shus) a. [L. fugax, 




swift.] Evanescent ; falling off 
early ; appl. petals, etc. (bot.}. 

fulcrate (ful'krat) a. [L. fulcrum, 
a support.] Having a fulcrum. 

fulcrum (ful'krum) a. [L. fulcrum, a 
support.] A supporting organ such 
as a tendril or stipule (bot.} ; part of 
the incus in the mastax of Rotifers ; 
spine-like scales on anterior fin-rays 
of many Ganoids (zool.}. 

function (fungk'shun) n. [L.functus, 
performed.] The normal action 
proper to any organ or part (phys.}. 

functional (fungk'shonal) a. [L. 
functus, performed.] Acting nor- 
mally ; acting or working part of an 
organ as distinct from the remainder 

fundiform (fun'diform) a. [L. funda, 
sling ; forma, shape.] Looped ; 
appl. a ligament of the penis 

fundus (fun'dus) n. [L. fundus, 
bottom.] The base of an organ, as 
of stomach, etc. (anat.}. 

fungicolous (funjik'olus) a. [L. 
fungus, mushroom ; colere, to in- 
habit.] Parasitic on Fungi (bot.}. 

fungiform (fun'jiform) a. [L. fungus, 
mushroom ; forma, shape.] Fun- 
goid or shaped like a fungus ; appl. 
tongue papillae (anat.}. 

fungivorous (funjiv'orus) a. [L. 
fungus, mushroom ; vorare, to de- 
vour.] Appl. fungus-eating animals 

fungous (fung'gus) a. [L. fungus, 
mushroom.] With character or 
consistency of fungus (bot.}. 

funicle (fu'nikl) n. [L. fumculus, a 
small cord.] An ovule stalk (bot.} ; 
a small cord or band of fibres 
especially in brain (anat.} ; a large 
double strand of cells passing from 
aboral end of coelom to aboral 
wall of zooecium of Molluscoidea 

funicular (funik'ular) a. [L. funic- 
ulus, small cord.] Consisting of 
a small cord or band ; pert, a funic- 
ulus (anat., zool.}. 

funiculus, see funicle. 

funnel (fun'el) n. [L. fundibulum, 
funnel.] The siphon of Cephalo- 
pods (zool.}. 

funnelfonn (fim'elform)a. [L. fundere, 
to pour ; forma, shape.] Widening 

gradually from a narrow base ; 
infundibuliform (bot.}. 

furca (fur'ka) n. [L. furca, fork.] 
The apophysis or entothorax of 
insect metathorax (zool.}. 

furcal (fur'kal) a. [L. furca, fork.] 
Forked ; appl. a branching nerve 
of the lumbar plexus (anat.}. 

furcate (fur'kat) a. [L. furca, fork.] 
Branching like the prongs of a 

furciferous (fursiferus) a. [L. furca, 
fork ; ferre, to carry.] Bearing a 
forked appendage, as some Insects 

furcula (fur'kula) n. [L. ftircula, 
dim. of furca, fork.] A forked 
process or structure, the merry- 
thought bone (anat.} ; a transverse 
ridge in the embryonic pharynx 

furred (furd) a. [M.E. furren, a 
sheath.] Having short decumbent 
hairs thickly covering the surface 

fuscin (fus'kin) n. {L.fttscus, tawny.] 
A brown pigment in the retinal 
epithelium (phys.}. 

fusi (fu'zl) n. phi. [L.fusus, spindle.] 
In spiders, organs composed of 
two retractile processes which issue 
from the mammillae and form the 
threads (zool.}. 

fusiform (fu'zTform) a. [L. fiisus, 
spindle ; forma, shape.] Spindle- 
shaped ; tapering gradually at both 
ends (zool.}. 

galactase (galak'tas) n. [Gk. gala, 
milk.] An enzyme, trypsin-like in 
action, found in milk (phys.}. 

galactophorous (gal'aktoforfis) a. 
[Gk. gala, milk ; pheretn, to carry.] 
Lactiferous ; appl. ducts of mam- 
mary glands (anat.}. 

galactosis (gal'akto'sis) n. [Gk. gala, 
milk.] Milk production (phys.}. 

galbulus (gal'bulus) n. [L. galbulus, 
cypress nut.] A modified cone 
with fleshy scales, as in cypress 
(bot.}. ^ 

galea (gal'ea) n. [L. galea, helmet.] 
A helmet-shaped petal, or other 




similarly-shaped structure (bot.} ; 
a muscle of the scalp (anat.} ; the 
outer division of the endopodite of 
the first maxillae of insects (zool.}. 

galeate (gal'eat) a. [L. galea, helmet.] 
Helmet-shaped (hot.}. 

gall(g61). [A.S.^//a,gall.] Bile, 
the secretion of the liver (phys.} ; 
any excrescence on plants caused 
by disease (hot.). 

gall-bladder, a small pear-shaped 
or spherical sac which stores the 
bile (anat.}. 

galvanotaxis (gal'vanotak'sis) n. [It. 
Galvani, physiologist.] Response or 
reaction to electrical stimulus (phys.}. 

galvanotropism (garvanot'ropizm) n. 
[It. Gal-vani, physiologist ; Gk. 
trope, a turning.] Galvanotaxis. 

gametal (game'tal) a. [Gk. gametes, 
spouse.] Pert, a gamete ; repro- 
ductive (biol.}. 

gametangium (gam'etan'jlum) . 
[Gk. gametes, spouse ; anggeion, 
vessel.] A structure producing 
sexual cells (hot.}. 

gametes (garnets') n. plu. [Gk. 
gametes, spouse.] Cells derived 
from gametocytes which conjugate 
and form zygotes (zool.} ; sexual 
cells (biol.}. 

gametlc (gamet'ik) a. [Gk. gametes, 
spouse.] Pert, gamete (biol.}. 

gametids (game'tidz) n. plu. [Gk. 
gametes, spouse.] Primary sporo- 
blasts destined to become gametes 

gametocyte (game'tosit) n. [Gk. 
gametes, spouse ; kytos, hollow.] 
The mother-cell of a gamete (zool.}. 

gametogenesis (game'tqjen'e'sis) . 
[Gk. gametes, spouse ; genesis, 
birth.] Gamete formation (biol.}. 

gametogeny (gam'etoj'enT) n. [Gk. 
gametes, spouse ; genos, birth.] 

gametogonlum (game'togo'nium) . 
[Gk. gametes, spouse ; gonos, off- 
spring.] A cell producing a gamete, 
a gametocyte (bot.}. 

gametophore (game'tofor) n. [Gk. 
gametes, spouse ; pherein, to bear.] 
A special part of a gametophyte on 
which gametangia are borne (bot.}. 

gametophyll (game'tofll) n. [Gk. 
gametes, spouse ; phyllon, leaf.] A 
modified leaf bearing sexual organs; 

a micro- or macro - sporophyll 

gametophyte (game'toflt) n. [Gk. 
gametes, spouse ; phyton, plant.] 
The gamete-forming phase in 
alternation of plant generations ; 
the sexual generation of plants ; cf. 
sporophyte (bot.}. 

gamic (gam'ik) a. [Gk. ganws, 
marriage.] Fertilized (biol.}. 

gamobium (gamo'bium) n. [Gk. 
gamos, marriage ; bios, life.] The 
sexual or medusoid generation in 
hydrozoan colonies (zool.}. 

gamodesmic (garn'odeVmik) a. [Gk. 
gamos, marriage ; desma, bond.] 
Having the vascular bundles fused 
together instead of separated by 
connective tissue (bot.}. 

gamogastrous (gam'ogas'trus) a. [Gk. 
gamos, marriage ; gaster, belly.] 
Appl. a pistil formed by union of 
ovaries, but with styles and stig- 
mata free (bot.}. 

gamogenesis (gam'ojen'esTs) n. [Gk. 
gamos, marriage ; genesis^ descent.] 
Sexual reproduction (biol.}. 

gamogenetic (gam'qjeneYik) a. [Gk. 
gamos, marriage ; genesis, descent.] 
Reproduced from union of sex 
elements ; sexual (biol.}. 

gamogony (gamog'onT) n. [Gk. gamos, 
marriage ; gone, descent.] Sporo- 
gony in Protozoa (zool.}. 

gamont (gamont') . \G\a. gamos, mur- 
riage;ons, a being.] A sporont (zool.}. 

gamopetalous (gam'opeYalus) a. [Gk. 
gamos, marriage ; petalon, petal.] 
With coherent petals ; mono- 
petalous (bot.}. 

gamophyllous (gain'oftl'iis) a. [Gk. 
gamos, marriage ; phyllon, leaf.] 
With united perianth leaves; mono- 
phyllous (bot.}. 

gamosepalous (gam'bsep'alus) a. [Gk. 
gamos, marriage ; sepalon, sepal.] 
With coherent sepals ; monosep- 
alous (bot.}. 

gamostele (gam'ostel') n. \G\i.gamos, 
marriage ; stele, pillar.] A stele 
formed from the fusion of several 
steles (bot.}. 

gamostelic (gam'dste'llk) a. [Gk. 
gamos, marriage ; stele, pillar.] 
Appl. the condition in which the 
steles of a polystelic stem are 
fused together (bot.}. 




gamostely (gam'oste'H) n. [Gk. 
gamos, marriage ; stele, pillar.] 
The arrangement of polystelic 
stems when the separate steles 
are fused together surrounded by 
pericycle and endodermis (dot.}. 

gangliar (gang'gllar) a. [Gk. gang- 
glion, little tumour.] Pert, a gan- 
glion or ganglia. 

gangliate (gang'gllat) a. [Gk. gang- 
glion, little tumour.] Having 

gangliform (gang'gliform) a. [Gk. 
gangglion, little tumour ; L. forma, 
shape.] In the form of a ganglion. 

ganglioblast (gang'glipblast) n. [Gk. 
gangglion, little tumour ; blastos, 
bud.] The mother-cell of a ganglio- 
cyte (anat.~). 

gangliocyte (gang'glioslt) n. [Gk. 
gangglion, little tumour ; kytos, 
hollow.] A ganglion cell outside 
the central nervous system (anat.). 

ganglioid (gang'glioid) a. \GY.gang- 
glion, little tumour ; eidos, resem- 
blance.] Like a ganglion (anat.). 

ganglion (gang'glion) n. [Gk. gang- 
glion, little tumour.] A mass of 
nervous matter containing nerve 
cells and giving origin to nerve 
fibres ; a nerve centre (anat.). 

ganglionated (gang'glTona'ted) a. 

gjk. gangglion, little tumour.] 
upplied with ganglia (anat.). 

ganglioneural (gang'glionu'ral) a. 
[Gk. gangglion, little tumour ; 
neuron, nerve.] Appl. a system of 
nerves, consisting of a series of 
ganglia connected by nerve strands 

ganglioneuron (gang'glionu'ron) n. 
[Gk. gangglion, little tumour ; 
neuron, nerve.] A nerve cell of a 
ganglion (anat.}. 

ganglionic (gang'glion'ik) a. [Gk. 
gangglion, little tumour.] Pert. 
consisting of, or in the neighbour- 
hood of a ganglion ; appl. a layer of 
the retina, arteries, arterial system 
of brain (anat.). 

ganglioplexus (gang'glioplgk'sus) n. 
[Gk. gangglion, little tumour ; L. 
plexus, twisted.] A diffuse ganglion 

ganoid (gan'oid) a. [Gk. ganos, 
sheen ; eidos, resemblance.] Appl. 
scales of ganoid fishes, rhomboidal, 

joined like parquetry and consisting 
of a layer of bone with a superficial 
enamel layer (zool.). 

ganoin (gan'oin) n. [Gk. ganos, 
sheen.] The outer layer of a 
ganoid scale, formed by -the coriuin 

gape (gap) n. [A.S. geapan, to open 
wide.] The distance between the 
open jaws of birds, fishes, etc. 

Gasserian ganglion, a large gan- 
glion on the sensory root of the fifth 
cranial nerve (anat.). 

gasteromycetous (gas'teromlse'tus) a. 
[Gk. gaster, belly ; mykes, a mush- 
. room.] Having the spores de- 
veloped in a peridium (oot.). 

gastraea (gastre'a) n. [Gk. gaster, 
stomach.] A hypothetical gastrula- 
like animal ; the ancestral Meta- 
zoan, according to Haeckel (zool.). 

gastraeum (gastre'iim) n. [Gk. gaster, 
stomach.] The ventral side of the 
body (anat.). 

gastral (gas'tral) a. [Gk. gaster, 
stomach.] Pert, stomach, as the 
gastral cavity, cortex, layer, etc. 

gastralia (gastra'lia) n. plu. [Gk. 
gaster, stomach.] Microscleres in 
the gastral membranes of Hexacti- 
nellids (zool.). 

gastric (gas'trik) a. [Gk. gaster, 
belly.] Pert, or in the region of 
the stomach ; appL arteries, glands, 
nerves, veins (anat.). 

gastrin (gas'trin) n. [Gk. gaster, 
stomach.] The hormone which is 
the result of the action of the 
salivary products on the gastric 
mucous membrane (phys.). 

gastrocentrous (gas'trosen'triis) a. 
[Gk. gaster, stomach ; L. centrum, 
centre.] Appl. vertebrae with 
centra formed by pairs of inter- 
ventralia, while the basiventralia 
are reduced (zool.). 

gastrocnemius (gas'trokne'mius) n. 
[Gk. gaster, belly ; kneme, the 
tibia.] The large muscle of the 
calf of the leg (anat.). 

gastrocoel (gas'trosel) n. [Gk. gaster, 
belly ; koilos, hollow.] The arch- 
enteron of a gastrula (emb.). 

gastrocolic (gas'trokol'ik) a. [Gk. 
gaster, stomach ; kolon, the gut.] 




Pert. stomach and colon ; appl. a 
ligament (anat.}. 

gastroduodenal (gas'trodu'ode'nal) a. 
[Gk. gaster, stomach ; L. duodeni, 
twelve each.] Pert, stomach and 
duodenum ; appl. an artery (anat.}. 

gastroepiplolc (gas'troep'iplo'ik) a. 
[Gk. gaster, stomach ; epiploon, the 
great omentum.] Pert, stomach 
and the great omentum ; appl. 
arteries, veins (anat.}. 

gastrointestinal (gas'tromtes'tinal) a. 
[Gk. gaster, stomach ; L. intus, 
withinj Pert, stomach and in- 
testines (anat.}. 

gastrolienal (gas'trolle'nal) a. [Gk. 
gaster, stomach ; L. lien, the 
spleen.] Pert, the stomach and 
spleen ; appl. ligament (anat.}. 

gastrolith (gas'trollth) n. [Gk. gaster, 
stomach ; lithos, stone.] A mass of 
calcareous matter found at certain 
seasons on each side of the gizzard 
of Crustaceans (zool.}. 

gastroparietal (gas'tropari'e'tal) a. 
[Gk. gaster, stomach ; L. paries, 
wall.] Pert, stomach and body 
wall (anat.}. 

gastrophrenic (gas'trofren'lk) a. [Gk. 
gaster, stomach ; phrenos, midriff.] 
Pert, stomach and diaphragm ; 
appl. ligament (anat.}. 

gastropod (gas'tropfid) n. [Gk. 
gaster, stomach ; pous, foot.J A 
mollusc with a ventral muscular 
disc adapted for creeping (zool.}. 

gastropores (gas'troporz) n. plu. 
[Gk. gaster, stomach ; poros, 
channel.] The larger pores, for 
nutrient persons, of hydroid Corals 

gastropulmonary (gas'tropul'monarl) 
a. [Gk. gaster, stomach ; L. pulmo, 
lung.] Pert, stomach and lungs 

gastrosplenic (gas'trosple'n'lk) a. 
[Gk. gaster, stomach ; splen, the 
spleen.] Pert, stomach and spleen 

gastrostege (gas'trostej) n. [Gk. 
gaster, belly ; stege, roof.] A 
ventral scale of snakes (zoo/.). 

gastrovascular (gas'trovas'kular) a. 
[Gk. gaster, stomach ; L. uasculum, 
a small vessel.] Serving both di- 
gestive and circulatory purposes, as 
canals of some Coelenterates (zool.}. 

gastrozooid (gas'trozo'oid) n. [Gk. 
gaster, stomach ; zoon, animal ; 
eidos, resemblance.] In coelenter- 
ate colonies, the nutrient person 
with mouth and tentacles (zool.}. 

gastrula (gas'troola) n. [Gk. gaster, 
stomach.] The cup- or basin- 
shaped structure formed by in- 
vagination of a blastula (emb.}. 

gastrulation (gas'troola'shun). [Gk. 
gaster, stomach.] The formation of 
a gastrula from a blastula by in- 
vagination (emb.}. 

geitonogamy (gl'tonog'amT) n. [Gk. 
geiton, neighbour ; gamos, marriage.] 
Fertilization of a flower by another 
from the same plant (bot.}. 

gelatigenous (jeTatij'Snus) a. [L. 
gelare, to congeal ; Gk. genos, 
offspring.] Gelatine - producing 

gelatine (jeTatin) n. [L. gelare, 
to congeal.] A jelly-like sub- 
stance obtained from animal tissue 

gelatinous (jelat'mus) a. [L. gelare, 
to congeal.] Jelly-like in consist- 
ency (zool.}. 

geminate (jem'mat) a. [L. gemini, 
twins.] Growing in pairs ; binate 

geminiflorous (jgm'iniflo'rus) a. [L. 
gemini, twins ; flos, flower.] Appl. 
a plant whose flowers are arranged 
in pairs (bot.}. 

gemma (jgm'a) n., gemmae (jgm'e, 
jgm'a) plu. [L. gemma, bud.] A 
bud or outgrowth of a plant or 
animal which develops into a new 
organism (biol.} ; hypothetical units 

gemmaceous (jgma'shus) a. [L. 
gemma, bud.] Pert, gemmae or 

gemmate (jgm'at) a. [L. gemma, 
bud.] Reproducing by bud-forma- 

gemmation (jgma'shon) n. [L. gemma, 
bud.] Bud-formation by means of 
which new independent individuals 
are developed in plants and animals 

gemmiferous (jgrnlfe'rus) a. [L. 
gemma, bud ; ferre, to bear.] Bud- 
bearing ; gemmate. 

gemmiform ( jgm'iform) a. [L. gemma, 
bud ; forma, shape.] Shaped like 




a bud ; appl. pedicellariae of Echino- 
derms (zool.). 

gemmiparous (jemip'arus) a. [L. 
gemma, bud ; parere, to produce.] 

gemmulation (jem'ula'shun) n. [L. 
gemma, bud.] Gemmule-formation. 

gemmule (je'm'ul) n. [L. gemmula, 
little bud.] A pangen (cyt.) ; one 
of the internal buds of Porifera 
arising asexually and coming into 
activity on the death of the parent 
organism (zool.). 

gena (je'na) n., genae (je'ne) plu. 
[L. gena, the cheek.] The cheek or 
side part of the head ; the antero- 
lateral part of an insect's head 

genal (je'nal) a. [L. gena, cheek.] 
Pert, the cheek ; appl. the facial 
suture of Trilobites and the angle 
of the cheek (zool.). 

geneology (je'neol'qji) n. [Gk. gene, 
descent ; logos, discourse.] The 
study of the development of indi- 
vidual and race ; Embryology and 
Palaeontology combined. 

genera (jSn'era), see genus. 

generalized (jen'erallz'd) a. [L. gen- 
eralis, of one, kind.] Combining 
characteristics of two or more 
groups, as in many fossils (pal.). 

generation (jen'era'shun) n. [L.gener- 
atio, reproduction.] Production ; 
formation ; the individuals of a 
species equally remote from a 
common ancestor, see alternation 
of generations. 

generative (jen'era'tiv) a. [L. genus, 
race.] Concerned in reproduction ; 
appl. the smaller of two cells into 
which a pollen grain primarily 
divides (bot.\ 

generic (jneYik) a. [L. genus, race.] 
Common to all species of a genus, 
see binomial nomenclature. 

genesis (jen'esis) n. [Gk. gignesthai, 
to produce.] Formation, produc- 
tion, or development of a cell, 
organ, individual, or species. 

genetic (jgnet'ik) a. [Gk. gignesthai, 
to produce.] Pert, production. 

genetic spiral, in spiral phyllotaxis, 
the imaginary spiral line following 
the points of insertion of successive 
leaves (dot.). 

genetics ( j enet'iks) n. [Gk. gignesthai, 

to produce.] That part of Biology 
dealing with heredity and varia- 

genial (jen'ial, jeni'al) a. [Gk. geneion, 
the chin.] Pert, the chin ; appl. 
chin-plates of Reptiles (zool.). 

genicular (jenTk'ular) a. [L. genicu- 
lum, little knee.] Pert, region 
of the knee ; appl. arteries, etc., also 
to ganglion of facial nerve (anat.). 

geniculate (jenik'ulat) a. [L. genicu- 
lum, little knee.] Bent like a knee- 
joint ; appl. a ganglion of the facial 
nerve (zool.) ; having the upper 
part of the filament forming an 
angle more or less obtuse with the 
lower (bot.). 

geniculum (jenik'ulum) n. [L. gen- 
iculum, little knee.] The part of 
the facial nerve in the temporal 
bone where it turns abruptly towards 
the stylo-mastoid foramen (anat.). 

genioglossal (jenl'oglos'al) a. [Gk. 
geneion, chin ; glossa, tongue.] Con- 
necting the chin and tongue ; appl. 
muscles (anat.). 

geniohyoid (jem'ohl'oid) a. [Gk. 
geneion, chin ; hyoeides, Y-shaped.] 
Pert, chin and hyoid ; appl. muscles 

genital (jen'ital) a. [L. gignere, to 
beget.] Pert, the region of the 
reproductive organs ; appl. cor- 
puscles, glands, ridge, tubercle, etc. 

genitals (jen'italz) n.plu. [L. gignere, 
to beget.] The organs of reproduc- 
tion, especially the external organs 

genitoanal (jen'itoa'nal) a. [L. gignere, 
to beget ; anus, the vent.] In the 
region of the genitals and anus 

genitocrural (jen'itokroo'ral) a. [L. 
gignere, to beget ; crus, leg.] In 
the region of the genitals and thigh ; 
appl. a nerve (anat.). 

genitoenteric (jen'itoenter'ik) a. [L. 
gignere, to beget ; Gk. enteron, gut.] 
Pert, genitals and intestine (anat.). 

genitofemoral (jen'itofem'oral) a. [L. 
gignere, to beget ; femur, thigh- 
bone.] Genitocrural. 

genoblast (jen'dblast) n. [Gk. genos, 
offspring ; blastos, bud.] A mature 
germ-cell exclusively male or female 




genu (jSn'u) n. [L. genu, knee.] A 
knee-like bend in an organ or part ; 
the anterior end of the corpus cal- 
losum (anat.). 

genus (je'nus) ., genera (jSn'era) plu. 
[L. genus, race.] A group of closely 
related species, in classification of 
plants or animals. 

genys (je'nis) n. [Gk. genys, jaw.] 
See gonys. 

geobios (je'obl'os) n. [Gk. ge, earth ; 
bios, life.] Terrestrial life one of 
Haeckel's terms (dial.}. 

geoblast (je'oblast) n. [Gk.^, earth ; 
blastos, bud.] A germinating plum- 
ule of which the cotyledons remain 
underground (bot.). 

geocarpic (je'okar'pik) a. [Gk. ge, 
earth ; karpos, fruit.] Having the 
fruits maturing underground (bot.). 

geology (jeol'ojl) n. [Gk. ge, earth ; 
logos, discourse.] The science 
dealing with the structure, activi- 
ties, and history of the earth. 

geomalism (jeom'alizm) n. [Gk. ge, 
earth ; omalos, level.] Response 
to the influence of gravitation (tot.). 

geophilous (jeofilus) a. [Gk. ge, 
earth ; philein, to love.] Living in 
or on the earth, the ground. 

geophyte (je'oflt) n. [Gk. ge, earth ; 
phyton, plant.] A plant which 
grows in the earth (tot.). 

geotaxis (je'otak'sis) n. [Gk. g*, 
earth ; taxis, arrangement.] Re- 
sponse to the laws of gravity. 

geotonus (je'oto'nus) n. [Gk. ge, 
earth ; tonos, tension.] Normal 
position in relation to gravity (tot.). 

geotropism (jeot'ropizm) n. [Gk. ge, 
earth ; trepein, to turn.] Tendency 
to respond to stimulus of gravity 
by turning towards it, as the down- 
ward growth of a root (dot.). 

gephyrocercal (gef'Iroser'kal, jSfi'ro- 
ser'kal) a. [Gk. gephyra, bridge ; 
kerkos, tail.] Appl. secondary di- 
phycercal caudal fin brought about 
by the reduction of the extreme tip 
of the heterocercal or homocercal 
fin (zool.). 

geratology (jer'atol'oji) n. [Gk.geras, 
old age ; logos, discourse.] Study 
of the factors of decadence. 

germ (jfirm) n. [L. gennen, bud.] 
A unicellular micro-organism ; a 
seed (tot.) ; a developing egg (zool.). 

germ-cell, a reproductive cell, opp. 
somatic ; a primitive male or female 
element (btol.). 

germ centre, an area of lymph- 
corpuscle division in nodules of 
lymph gland tissue (anat.). 

germ-disc, a small green cellular 
plate of the germ tube of liverworts 

germ layer, an early differentiated 
layer of cells (emb.). 

germ nucleus, an egg or sperm 
nucleus (emb.). 

germ plasm, idioplasm ; the physi- 
cal basis of inheritance. 

germ pore, the exit pore of a germ 
tube in the spore integument (bot.). 

germ stock, the stolon in certain 
Tunicates (zool.). 

germ theory, biogenesis ; the theory 
that living organisms can be pro- 
duced or developed only from living 
organisms (btol.). 

germ tube, the short filamentous 
tube put forth by a germinating 
spore (bot.). 

germ vitellarium, an organ of 
Platyhelminths producing both ova 
and vitelline material. (sool.). 

germ yolk gland,-^-m. some Rhabdo- 
coels, an embryonic structure con- 
sisting of the fertile portion of the 
egg and a sterite\ portion which 
functions as a yolk gland feeding 
the fertite ftprlion (zool.). 

germarium (jerma'rium) n. [L. ger- 
men, bud.] An ovary (zool.). 

germen (jer'men) n. [L. germen, 
bud.] A mass of undifferentiated 
cells, the primary form of the germ 

germinal (jer'mmal) a. [L. germen, 
bud.] Pert, a seed, a germ-cell, or 

germinal bands, two sets of rows of 
cells in early development of 
Annulates (zool.). 

germinal cells, the cells concerned 
in reproduction, set apart early in 
embryonic life (emb.). 

germinal disc, the disc-like area of 
an egg yolk on which segmentation 
first appears (emb.). 

germinal epithelium, the layer of 
columnar epithelial cells covering 
the stroma of an ovary (emb.). 

germinal layers, the primary layers 




of cells in a developing ovum, epi- 
blast, hypoblast, and later mesoblast 

germinal spot, the nucleus of an 
ooplasm (emb.). 

germinal vesicle, the nucleus of an 
egg, before formation of polar- 
bodies (emb.). 

germination (jer'inma'shun) n. [L. 
germen, bud.] Beginning of growth ; 
budding ; development (bot.). 

germiparity (jeYmipar'iti) n. [L. 

frmen, bud ; parere, to beget.] 
eproduction by germ-formation. 

germogen ( j eVmoj Sn') n. [L. germen, 
bud ; Gk. genos, offspring.] The 
central cell of the gastrula-like 
phase, or infusorigen, in the 
development of the Rhombozoa ; 
the residual nucleus, or unused 
portion, after formation of the 
rhpmbogen by division of the 
primary germogen or primitive 
central cell (zool.). 

gestation (jSsta'shun) n. [L. gerere^ 
to carry.] The intra-uterine period 
in the development of an embryo 

giant cells, large nerve-cells in 
Annelids ; myeloplaxes ; osteo- 
clasts ; large multinuclear proto- 
plasmic masses found in marrow, 
spleen (anat.). 

giant fibres, greatly enlarged and 
modified nerve-fibres running longi- 
tudinally through the ventral nerve 
cord of some invertebrates, as 
Worms (zool.). 

gibbous (gib'us) a. [L. gibbus, 
humped.] Inflated ; saccate or 
pouched, as the lateral sepals of 
Cruciferae (bot.). 

gill (gll) n. [M.E. gille, gill.] A 
plate-like or filamentous outgrowth ; 
respiratory organ of water-inhabit- 
ing animals (zool.) ; one of a number 
of lamellae radiating from the stalk 
of a mushroom (&?/.). 

gill arch, part of the visceral skele- 
ton in the region of functional gills ; 
branchial arch (zool.). 

gill basket, the branchial skeleton 
of lampreys, composed of continu- 
ous cartilage (zool.). 

gill book, the respiratory organ of 
certain Arachnids, consisting of a 
large number of leaf-like structures 

between which the water circulates 

gill cleft, a branchial cleft formed 
on the side of the pharynx (zool.). 

gill cover, an operculum; 

gill helix, a spirally coiled gill-like 
organ in certain Clupeidae (zool.). 

gill plume, the gill or ctenidium of 
the majority of Gastropods (zool.). 

gill pouch, an oval pouch containing 
gills and communicating directly or 
indirectly by a duct with the 
exterior, seen in Myxine and Petro- 
myzon (zool.). 

gill rakers, small spine-like struc- 
tures attached in a single or double 
row to branchial arches to prevent 
escape of food (sool.). 

gill remnants, epithelial, post- 
branchial, or suprapericardial bodies 
arising in the pharynx of higher 
vertebrates (zool.). 

gill rods, oblique gelatinous rods 
supporting the pharynx in Cephalo- 
chorda (zool.). 

gill slits, a series of perforations 
leading from pharynx to the exterior, 
persistent in lower vertebrates, 
embryonic in higher (zool.). 

gingival (jinjl'val) a. [L. gingivae, 
gums.] Pert, the gums. 

ginglymoid (gmg'glTmoid) a. [Gk. 
gingglymos, hinge - joint.] Con- 
structed like a hinge-joint (anat.). 

ginglymus (ging'glimus) n. [Gk. 
gingglymos, hinge-joint.] An ar- 
ticulation constructed to allow 
motion in one plane only (anat.). 

girdle (ger'dl) n. [A.S. gyrdan, to 
gird.] In appendicular skeleton, 
the supporting structure at shoulder 
and hip, each consisting typically 
of one dorsal and two ventral 
elements (anat.). 

gizzard (giz'ard) n. [M.E. gizer, 
gizzard.] In birds, the muscular 
grinding chamber of the alimentary 
canal ; the proventriculus of insects 

glabella (glabel'a) n. [L. glaber, 
bald.] The space on the forehead 
between the superciliary ridges 
(anat.) ; the elevated median region 
of the cephalic shield of Trilobites 

glabrate (glab'rat) a. [L. glaber, 
smooth.] Becoming smooth; glab- 




rescent ; with a nearly smooth sur- 
face (hot.}. 

glabrescent, see glabrate. 

glabrous (glab'rus) a. [L. g/afer, 
smooth.] With a smooth, even 

gladiate (glad'iat) a. [L. gladius, 
sword.] Shaped like a sword (bot.). 

gladiolus (glad'io'lus) n. [L. gladiolus, 
small sword.] The middle or largest 
part of the sternum (anat.). 

gladius (glad'ius) n. [L. gfaSta, 
sword.] The pen of a cuttle-fish 

gland cell, an isolated secreting 
cell ; a cell of glandular epithelium. 

glands (glandz) n. plu. [L. glans, 
an acorn.] Single cells or masses 
of cells specialized for the elabora- 
tion of secretions either for use in 
the body or for excretion (anat.). 

glandula (glan'dula) n. \L. glandula, 
small acorn.] An arachnoid granu- 
lation on the outer surface of the 
dura mater (anat.). 

glandular (glan'dular) a. [L. glandula, 
small acorn.] Pert, a gland ; with 
secreting function (zool.) ; bearing 
a gland (hot.}. 

i.landular epithelium, the tissue of 
glands, composed of polyhedral 
c 'lumnar or cubical cells whose 
protoplasm contains the material 
secrtted (phys.). 

glandular tissue, tissue of single 
or massed cells, parenchymatous 
and filled with granular protoplasm, 
adapted for secretion of aromatic 
substances (hot.). 

glandule (glan'dul) n., see glandula. 

glandulose-serrate (glan'dulos-seYat) 
a. [L. glandula, small acorn ; 
serratus, sawn.] Having the serra- 
tions tipped with glands (bot.). 

glans (glanz) n. [L. glans, acorn.] 
A nut ; a hard, dry, indehiscent 
one-celled fruit like an acorn (bot.) ; 
a gland, especially the glans penis 

glaucescent (glosgs'gnt) a. [L. glau- 
cus, sea-green.] Somewhat glaucous 

glaucous (glok'us) a. [L. glaucus, 
sea-green.] Covered with a bluish- 
green bloom (bot.). 

gleba (gle'ba) n. [L. gleba, clod.] 
The central part of the sporophore 

in certain Fungi ; the spore-form- 
ing apparatus in certain plants 

glebula (gle'bula) . [L. glebula, 
small clod.] A small prominence 
on a lichen thallus (bot.). 

glenohumeral (gle'nohu'mSral) a. 
[Gk. glene, socket ; L. humerus, 
the humerus.] Pert, glenoid fossa 
and humerus ; appl. ligaments 

glenoid (gle'noid) a. [Gk. glene, 
socket ; eidos, resemblance.] Like 
a socket ; appl. especially to the 
cavity into which the head of the 
humerus fits, the mandibular fossa, 
and ligaments (anat.). 

glenoidal labrum, a fibro-carti- 
laginous rim attached round the 
margin of glenoid cavity and 
acetabulum (anaf.). 

glia (gll'a, gle'a) n. [Gk. glia, glue.] 
A cell of the neuroglia ; a support- 
ing cell of nervous tissue (phys.). 

Glisson's capsule, a thin fibrous 
capsule within the tunica serosa of 
the liver (anat.). 

globate (glo'bat) a. [L. globus, globe.] 

globigerina ooze (globg'erl'na ooz), 
sea-bottom mud, which is largely 
composed of foraminifera shells 

globin (glo'bin) n. [L. globus, globe.] 
The protein constituent of haemo- 
globin (phys.). 

globoid (glo'boid) n. [L. globus, 
globe ; Gk. eidos, resemblance.] A 
spherical body of aleurone grains; 
a double phosphate of calcium and 
magnesium (bot.). 

globose (globes') a. [L. globus, globe.] 
Spherical or globe-shaped. 

globular (glob'ular) a., see globose. 

globule (glSb'ul) n. [L. globulus, 
small globe.] Any minute spher- 
ical structure ; the antheridium of 
Characeae (bot.). 

globulin (glob'ulin) n. [L. globus, 
globe.] A proteid such as fib- 
rinogen, vitellin (phys.). 

globulose (glob'ulos) a. [L. globus, 
globe.] Spherical ; consisting of, 
or containing globules. 

glochidiate (glokTd'Iat) a. [Gk. 
glochis, arrow - point.] Furnished 
with barbed hairs (bot.). 




glochidium (glokid'ium) n. [Gk. 
glochis, arrow-point.] Hairs bear- 
Ing barbed processes seen on the 
massulae of certain Rhizocarps 
(bot.} ; the larva of fresh -water 
mussels such as Unio and Anodon 

gloea (gle'a) n. [Gk. gloia, glue.] 
An adhesive secretion of some 
Protozoa (zool.}. 

glomerular (glomer'ular) a. [L. 
glomus, ball.] Pert, or like a 
glomerulus (anat.}. 

glomerulate (glomeYulat) a. [L. 
glomus, ball.] Arranged in 

glomerule (glom'grul) n. [L. glomus, 
ball.] A condensed cyme of almost 
sessile flowers ; a compact cluster 

glomeruliferous (glomgr'ulTf'grus) a. 
[L. glomus, ball ; ferre, to carry.] 
Having the flowers arranged in 
glomerules (bot.}. 

glomerulus (glomer'ulus) n. [L. 
glomus, ball.] A network of capil- 
lary blood-vessels ; the inturned 
portion of a Bowman's capsule 
(zool.} ; an oval body terminating 
the olfactory fibre in the rhinen- 
cephalon (anat.}. 

glomus (glo'mus) n., glomera (glonV- 
6ra) plu. [L. glomus, ball.] A 
number of glomeruli run together 
(zool.} ; the coccygeal and carotid 
skeins of the suprarenal glands 

glossa (glos'a) n. [Gk. glossa, 
tongue.] A tongue-like projection 
in the middle of the labium of 
insects (zool.}. 

glossal (glos'al) a. [Gk. glossa, 
tongue.] Pert._ the tongue. 

glossarium (glosa'rium) n. [Gk. glossa, 
tongue.] Theslender-pointedglossa 
of certain Diptera (zool.}. 

glossate (glos'at) a. [Gk. glossa, 
tongue.] Having a tongue or 
tongue-like structure (zool.}. 

glossoepiglottic (glos'ogp'iglot'ik) a. 
[Gk. glossa, tongue ; epi, upon ; 
glotta, tongue.] Pert, tongue and 
epiglottis ; appl. folds of mucous 
membrane (anat.}. 

glossohyal(glos'6hl'al) n. \Gk.glossa, 
tongue ; hyoeides, Y-shaped.] The 
median basihyal of fishes (zool.}. 

glosso-kinaesthetic area, a brain 
area in Broca's convolution immedi- 
ately connected with speech (phys.}. 

glossopalatine (glos'opal'atm) a. 
[Gk. glossa, tongue ; L. palatus, 
the palate.] Connecting tongue 
and palate ; appl. arch, muscle 

glossophagine (glosof'ajin) a. [Gk. 
glossa, tongue ; phagein, to eat.] 
Securing food by means of the 
tongue (zool.}. 

glossopharyngeal (glos'ofarTn'jeal, 
-far'inje'al) a. [Gk. glossa, tongue ; 
pharynx, gullet.] Pert, pharynx 
and gullet ; appl. the ninth cranial 
nerve (anat.}. 

glossopodium (glos'dpo'dium) n. [Gk. 
glossa, tongue ; pous, foot.] The 
sheathing leaf-base of Isoetes 

glossotheca (glos'othe'ka) n. [Gk. 
glossa, tongue ; theke, box.] The 
proboscis-covering part of a pupal 
integument of insects (zool.}. 

glottis (glot'is) n. [Gk. glotta, 
tongue.] The opening into the 
windpipe (anat.}. 

glucase (glook'as) n. [Gk. glykus, 
sweet.] A plant enzyme which 
produces grape sugar from maltose 

glucoproteins, compounds of pro- 
tein with a carbohydrate, including 
mucins and mucoids (phys.}. 

glucosamine (glook'osam'in) ;/. [Gk. 
glykus, sweet.] A nitrogenous sub- 
stance with a reducing power, 
obtained from chitin, and dextro- 
rotary (phys.}. 

glucose (glook'os) n. [Gk. glykus, 
sweet.] The grape sugar of plants 
and animals (phys.}. 

gluma (gloom'a) n. [L. gluma, husk.] 
A bract at the base of a grass in- 
florescence or spikelet (bot^. 

glumaceous (glooma'shus) a. [L. 
gluma, husk.] Dry and scaly like 
glumes (bot.}. 

glume (gloom) n., see gluma. 

glumiferous (gloomlf'e'rus) a. [L. 
gluma, husk ; ferre, to bear.] 
Bearing or producing glumes (bot.}. 

glumiflorus (gloom'iflo'rus) a. [L. 
gluma, husk ; flos, flower.] Having 
flowers with glumes or bracts at 
their bases (bot.}. 




gluteal (gloot'eal) a. [Gk. gloutos, 
buttock.] Pert, or in the region of 
the buttocks ; appl. artery, muscle, 
nerve, tuberosity, vein (anaf.). 

gluten (gloor/gn) n. [L. gluten, ghie.] 
A tough substance obtainable from 
some grains. 

gluteus (gloot'eus) . [Gk. gloutos, 
buttock.] Name given to certain 
muscles of the buttock (anat.). 

glutinous (gloot'mus) a. [L. gluten, 
glue.] Having a sticky or adhesive 
surface (dot.). 

glycerin (glis''erin) n. [Gk. glykos, 
sweet.] The sweet principle of 
natural fats and oils (phys.). 

glycerol (glis'6r61) n.,- see glycerin. 

glycogen (glfkoj^n) n. [Gk. glykos, 

sweet.] Animal starch (phys.). 

glycolysis (gllkol'isls) n. [Gk. glykos, 
sweet ; lyein, to loosen.] Decom- 
position of sugar by hydrolysis 

glycosecretory (gll'kosekre'tori) a. 
[Gk. glykos, sweet ; L. secretus, set 
apart!] Connected with the secre- 
tion of glycogen (phys.). 

gnathic (gnath'ik, nath'ik) a. [Gk. 
gnathos, jaw.] Pert, the jaw (zool.). 

gnathism (gnath'Izm, nath'izm) n. 
[Gk. gnathos, jaw.] Formation of 
jaw with reference to the degree 
of projection. 

gnatbites (gnath'lts, nath'lts) n. plu. 
[Gk. gnathos, jaw.] The buccal 
appendages of insects. 

gnathobase (gnath'obas, nath'obas) n. 
[Gk. gnathos, jaw ; basis, base.] 
An inwardly turned masticatory 
process on the protopodite of 
appendages near the mouth in 
Crustacea (zool.). 

gnathopod (gnath'opod, nathopod) n. 
[Gk. gnathos, jaw ; pous, foot.] Any 
Crustacean limb in the oral region 
modified to assist with the food 

gnathopodite (gnathop'ddit, nathop'- 
ddlt) n. [Gk. gnathos, jaw ; pous, 
foot.] Amaxillipedof an Arthropod 

gnathostegite (gnathSs'tgglt, nathos'- 
tejit) n. [Gk. gnathos, jaw ; stege, 
roof.] A covering plate for the 
mouth parts of some Crustaceans 

gnathostomatous (gnath'ostSm'atus, 

nath'ostSm'atus) a. [Gk. gnathos, 
jaw ; stoma, mouth.] With jaws at 
the mouth. 

gnathotheca (gnath'othe'ka, nath'- 
othe'ka) n. [Gk. gnathos, jaw ; 
theke, case.] The horny outer 
covering of a bird's lower jaw 

goblet cells, mucus-secreting cells 
of most columnar epithelia (phys.). 

gomphosis (g6mfo'sis). \G\a.gomphos, 
a bolt] Articulation by insertion 
of a conical process into a socket, 
as of roots of teeth into alveoli 

gonad (gon'ad) n. [Gk.gone, descent.] 
A sexual gland, either ovary or 
testis (zool.). 

gonaduct (gSn'adukt) n. [Gk. gonos, 
offspring ; L. ducere, to lead.] A 
genital duct ; a duct leading from 
the gonad to the exterior ; a gono- 
duct (zool.). 

gonanglum (gon5n'jtum) n. [Gk. 
gone, seed ; anggeion, vessel.] A 
gonotheca, a dilated cup of peri- 
sarc protecting the blastostyle of 
Calyptoblastea (zool.). 

gonapophyses (gon'apof isez) n. plu. 
[Gk. gone, seed ; apo, from ; phyein^ 
to grow.] The chitinous outgrowths 
subserving copulation in insects ; 
the component parts of the sting 

goniale (gon'Iale, gonial'a) n. [Gk. 
gonia, corner.] In some verte- 
brates, a bone of the lower jaw 
beside the articular (anat.). 

gonidangium (gon'idan'jium) n. [Gk. 
dim. otgone, seed ; anggeion, vessel.] 
A structure producing or contain- 
ing gonidia (bot.). 

gonldia (gonid'ia) n. plu. ; gonidium 
(gonid'Ium) sing. [Gk. dim. of gone, 
seed.] Asexual non-motile repro- 
ductivecells produced upon gameto- 
phytes (dot.). 

gonidial (gonid'lal) a. [Gk. dim. of 
gone, seed.] Pert, gonidia (dot.). 

gonidiferous (gonldlf'6rus) a. [Gk. 
dim. of gone, seed ; L. ferre, to 
carry.] Bearing or producing 
gonidia (dot.). 

gonidimlum (gSn'Idfm'lum) n. Gk, 
dim. of gone, seed.] A gonidial 
structure smaller than a gonidium 
and larger than a gonimium (dot.). 




gonidiogenous (gonid'ioj'enus) a. [Gk. 
dim. of gone, seed ; genos, offspring.] 
Bearing or producing gonidia ; 
gonidiferous (bot.). 

gonidioid (gonid'ioid) a. [Gk. dim. 
of gone, seed ; et'dos, resemblance.] 
Like a gonidium ; appl. certain 
Algae (Sot.). 

gonidiophore (gonid'iofor) n. [Gk. 
dim. of gone, seed ; pherein, to bear.] 
An aerial hypha supporting a goni- 
dangium (bot.). 

gonidiophyll (gonid'iofil) n. [Gk. 
dim. of gone, seed ; phyllon, leaf.] 
A gametophyte leaf bearing gonidia 

gonimium (gSmm'ium) n. [Gk. 
gonimos, productive.] A bluish- 
green gonidium of certain Lichens 

gonimoblasts (gon'imoblasts) n. plu. 
[Gk. gonimos, productive ; blastos, 
bud.] Filamentous outgrowths of 
a fertilized carpogonium of certain 
Algae (dot). 

gonion (go'nlon) n. [Gk. gonia, angle.] 
The angle point on the lower jaw 

gonoblast (gon'oblast) n. [Gk. gonos, 
offspring ; blastos, bud.] A repro- 
ductive cell (zool.). 

gonoblastid (gSn'oblas'tid) n. [Gk. 
gonos, offspring ; blastos, bud.J A 
blastostyle of Hydrozoa (zool.). 

gonocalyx (gSn'oka'liks) n. [Gk. 

finos, offspring ; kalyx, a cup.] 
he bell of a medusiform gonophore 

gonocheme (gSn'okem) n. [Gk. gonos, 
offspring ; ochema, support] A 
medusoid bearing sex-cells in the 
Hydrozoa (zool.). 

gonochorism (gon'oko'rizm) n. [Gk. 
gonos, offspring ; chorisein, to 
divide.] The history or develop- 
ment of sex distinction. 

gonocoele (g6n'6sel) n. [Gk. gone, 
seed ; koilos, hollow.] The cavity 
containing the gonads (zool.). 

gonocytes (gon'oslts) n. plu. [Gk. 
gone, seed ; kytos, hollow.] Sexual 
cells of Sponges ; the mother-cells 
of ova and spermatozoa (zool.). 

gonodendron (gon'6d6n'dron) n. [Gk. 
gonos, offspring ; dendron, tree.] 
A branching blastostyle in Physalia 

gonoduct (gon'odiikt') n., see gona- 

gonophore (gon'ofor) n. [Gk. gone, 
seed ; pherein, to bear.] An elonga- 
tion of the thalamus between corolla 
and stamens (bot.) ; a reproductive 
zooid in a hydroid colony (zool.). 

gonoplasm (gon'oplazm) n. [Gk. gone, 
seed ; plasma, something moulded.] 
The generative part of protoplasm 

gonopore (gon'opor) n. [Gk. gone, 
seed ; poros, channel.] The repro- 
ductive aperture of female Nema- 
todes (zool.). 

gonosome (gon'osom) n. [Gk. gone t 
seed ; soma, body.] All the repro- 
ductive zooids of a hydrozoan 
colony (zool.). 

gonosphaerium (gon'osfe'rium) n. 
[Gk. gone, seed ; sphaira, globe.] 
An oosphere (bot.). 

gonostyle (gon'ostll) n. [Gk. gone, 
seed ; stylos, pillar.] The blasto- 
style ; sexual palpon or siphon of 
Siphonophora (zool.). 

gonotheca (gSn'othe'ka) n. [Gk. gone, 
seed ; theke, cup.] A transparent 
protective expansion of the perisarc 
round a blastostyle or gonophore 

gonotome (gon'otom) n. [Gk. gone, 
seed ; temnein, to cut.] An embry- 
onic segment containing the pri- 
mordium of the gonad, comparable 
to a nephrotome (smb.). 

gonozooid (gon'b'zd'oid) n. [Gk. gone, 
seed ; zoon, animal ; eidos, resem- 
blance.] A gonophore or repro- 
ductive individual of a hydrozoan 
colony; a zooid containing a gonad 

gonydial (gonld'ial) a. [Gk. genys, 
lower jaw.] Pert, a gonys (zool.). 

gonys (gon'is) n. [Gk. genys, lower 
jaw.] The lower part of a bird's 
bill (zool.). 

Graaflan (graf'Ian, graf'ian) follicle, 
a vesicular spherical capsule sur- 
rounding an ovum, the cells of the 
capsule being morphologically equal 
to the ovum ; an ovisac with de- 
veloping ova. 

gracllis (gras'ilis) n. [L. gracilis, 
slender.] A superficial muscle of 
the thigh (anat.). 

graduated (grad'uatgd) a. [L. gradus^ 




step.] Tapering ; becoming longer 
or shorter by steps. 

grain (gran) n. [L. granum, grain.] 
Theseedof cereals ; a granular prom- 
inence on the back of a sepal (dot.}. 

graminifolious (gram'fnifo'llus) a. 
[L. gramen, grass ; folium, leaf.] 
With grass-like leaves (bot.}. 

graminivorous (gram'miv'orus) a. 
[L. gramen, grass ; vorare, to eat.] 
Grass-eating (zool.}. 

granellae (graneTe) n. plu. [L. dim. 
of granum, grain.] Small oval, 
refractile granules consisting chiefly 
of barium sulphate, found in the 
tubes of certain Sarcodina (zool.}. 

granellarium (gran'gla'rium) n. [L. 
dim. of granum, grain.] The system 
of granellae-containing tubes of 
Sarcodina (zool.}. 

granose (gran'os) a. [L. granum, 
grain.] In appearance like a chain 
of grains, like some insect antennae ; 
moniliform (zool."). 

granular (gran'ular) a. [L. granum, 
grain.] Consisting of grains or 
granules ; appearing as if made up 
of granules (zool.}. 

granulation (gran'ula'shun) n. [L. 
granum, grain.] A grain-like eleva- 
tion or eminence ; appl. arachnoid 
elevations on the outer surface of 
the dura mater (anat.}. 

granule (gran'ul) n. [L. granulum, 
small grain.] A small particle of 
matter ; a small grain (hot.). 

granule cells, ovoid or spheroid 
cells formed of soft protoplasm 
containing basiphil granules. 

granule glands, the prostate glands 
of flatworms. 

graphiohexaster (graf i6h6ksas'ter) n. 
[Gk. graphein, to write ; hex, six ; 
aster, star.] A hexaster spicule 
with long outwardly-directed fila- 
mentous processes from four of the 
rays (zool.}. 

grater (gra'ter) n. [O.F. grater, to 
scrape.] One of the denticles of a 
Eunice (zool.}. 

gravity (grav'iti) n. [L.gravis, heavy.] 
The force of attraction of all bodies 
towards each other ; the tendency 
of terrestrial bodies to be drawn 
towards the earth's centre (phys.}. 

green glands, the excretory organs 
of certain Crustacea (zool.}. 

gregaloid (grgg'aloid) a. [L. grex, 
flock; Gk. eidos, like.] Appl. a 
colony of Protozoa of indefinite 
shape, usually with a gelatinous 
base, formed by incomplete division 
of individuals or partial union of 
adults (zool.}. 

gregarious (grgga'rius) a. [L. grex, 
flock.] Tending to herd together ; 
colonial ; growing in clusters (biol.}. 

grey matter, nerve tissue abund- 
antly supplied with nerve cells, of 
greyish colour, internal to white 
matter in spinal cord, external in 
cerebrum (anat.}. 

grey nerve-fibres, semitransparent, 
grey or yellowish-grey, gelatinous 
non-medullated nerve-fibres, com- 
prising most of the fibres of the 
sympathetic system and some of 
the cerebro-spinal (anat.}. 

groin (groin) n. [lct\.grein, branch.] 
The depressed part of the body 
between abdomen and thigh (anat.}. 

groove (groov) n. [Dut. groef, 
channel.] Any channel, furrow, or 
depression, as carotid, costal, optic, 
primitive vertebral groove (anat.}. 

group (groop) n. [F. groupe, group.] 
A number of plants, or animals, 
related to one another, and con- 
sidered collectively (biol.}. 

growing point, a part of the plant 
body at which cell-division is 
localized, generally terminal and 
composed of meristematic cells 

growth, increase in substance of 
plant or animal, due to anabolism 
being greater than katabolism 

growth rings, see annual rings 

grumose (groom'os) a. [L. grutnus, 
hillock.] Clotted ; knotted ; col- 
lected into granule masses (bot.}. 

grumous (groom'us), see grumose. 

guanin (gwan'In) n. [Peruvian, huano, 
dung.] A substance contained in 
guano, also in some plants and 
certain mammalian glands ; that 
found in fish corium forms the 
basis of artificial pearl (biol.}. 

guanylic (gwan'ilik) a. [Peruvian, 
huano, dung.] Appl. a nucleic 
acid, yielding guanin, found in the 
pancreas (phys.}. 




guard (gard) n. [O.F. garder, to 
guard.] The rostrum of a Belem- 
nite (pal.}. 

guard cells, cells surrounding the 
stomata of the aerial epidermis of 
plant tissue (dot.}. 

gubernacular (goo'bernak'ular) a. 
[L. gubemare, to govern.] Pert. 
the gubernaculum. 

gubernaculum (goo'bernak'ulum) n. 
[L. gubemare, to govern.] A cord 
stretching from the epididymis to 
the wall of the scrotum (anat.) ; 
strands of blastostylar ectoderm 
between gonophore and gonotheca 
in the Hydromedusae ; a posterior 
flagellum functioning as a rudder 

guest Insect, an insect living or 
breeding in the nestof another (zoo/.}. 

gula (gu'la) n. [L. gula, gullet.] 
The upper part of the throat ; the 
median ventral piece of an insect's 
head (zoo/.). 

gular (gu'lar) n. [L. gula, gullet] 
An anterior unpaired horny shield 
on the plastron of Chelonia (zoo/.). 

gullet (gul'et) n. [L. gula, gullet.] 
The oesophagus; a muscular canal 
extending from mouth cavity to 
stomach ; the canal between the 
cell-mouth or cytostome and the 
endoplasm of Ciliata (zoo/.). 

gum (gum) n. [L.gummi, gum.] An 
exudation of certain plants and 
trees ; a vegetable mucilage (hot.). 

gummiferous (gurmf'eYus) a. [L. 
gummi, gum ; ferre, to carry.] 
Gum-producing or exuding (dot.). 

gummosis (giimd'sTs) n. [L. gummi, 
gum.] Condition of plant tissue when 
cell-walls become gummy (dot.). 

gums (gumz) n. plu. [A.S. goma, 
jaw.] The thick tissues investing 
the jaws (anat.). 

gustatory (gus'tatori) a. [L. gustare, 
to taste.] Pert, sense of taste ; appl. 
cells, hairs, pores, nerves (anat.). 

gustatory calyculus, a taste bud ; 
an end-cell or end-organ of taste 
consisting of a group of gustatory 
cells (anat.). 

gut (gut) n. [A.S. gut, a channel.] 
The intestine or part thereof, 
according to the structure of the 
animal (zoo/.). 

gutta (gut'a) n. [L. gutta, drop.] 

A small spot of colour on an 
insect's wing or elsewhere (zoo/.). 

guttation (guta'shun) n. [L. gutta, 
drop.] Formation of drops of 
water on plants from moisture in 
the air (dot.). 

guttiform (gut'iform) a. [L. gutta, 
drop ; forma, shape.] Drop-like ; 
in the form of a drop (zoo/.). 

guttulate (gut'ulat) a. [L. guttula, 
small drop.] In the form of a 
small drop, as markings (zoo/.). 

gymnanthous (jimnan'thus) a. [Gk. 
gymnos, uncovered; anthos, flower.] 
With no floral envelope; achlamyd- 
eous (dot.). 

gymnetrous (jimne'trus) a. [Gk. 
gymnos, naked ; etron, abdomen.] 
Without an anal fin (zoo/.). 

gymnoarian (jimnoa'rian) a. [Gk. 
gymnos, naked.] Appl. gonads 
when naked, or not enclosed in 
coelomic sacs ; opp. cystoarian 

gymnoblastic (jlm'noblas'tik) a. [Gk. 
gymnos, naked ; blastos, bud.] With- 
out hydrothecae and gonothecae ; 
appl. certain of the Coelenterates 

gymnocarpous (jim'nokar'pus) a. 
[Gk. gymnos, uncovered ; karfios, 
fruit.] With naked fruit ; appl. 
Lichens with uncovered apothecia, 
Mosses with expanded hymenium 

gynmocidlum (jTm'nosid'ium) n. 
[Gk. gymnos, uncovered.] A basal 
swelling of certain moss capsules 

gymnocyte(jTm'nosit). [Gk. gymnos, 
uncovered ; kytps, hollow.] A cell 
without a defining cell-wall (diol.). 

gymnocytode ( jim'nti sl'tod), a cytode 
without cell-wall or nucleus a term 
used by Haeckel (diol.). 

gymnogenous (j!mnqj'6nus) a. [Gk. 
gymnos, naked ; genos, offspring.] 
'Naked when bo'rn ; appl. birds 

gymnogynous (jimnqj'inus) a. [Gk. 
gymnos, naked ; gyne, woman.] 
With exposed ovary (dot.). 

gymnoplast (jim'noplast) n. [Gk. 
gymnos, naked ; plastos, formed.] 
Protoplasm without definite forma- 
tion or cell-wall (diol.). 

gymnorhlnal (jTm'nori'nal) a. [Gk. 




gymnos, naked ; rhis, nose.] With 

nostril region not covered by 

feathers, as in some birds (zoo/.). 

gymnosomatous (jim'nosom'atus) a. 

ik. gymnos, naked ; soma, body.] 
aving no shell or mantle, as 
certain Molluscs (zoo/.). 

gymnospermous (jimnospeYmus) a. 
[Gk. gymnos, uncovered ; spenna, 
seed.] Having seeds not enclosed 
in a true ovary, as in the Conifers 

gymnospore (jfm'nospor) n. [Gk. 
gymnos, naked ; sporos, seed.J A 
naked germ not enclosed in a 
protective envelope (oto/.). 

gymnostomatous ( jim'nostom'atus) a. 
[Gk. gymnos, naked ; stoma, mouth.] 
Naked-mouthed ; having no peri- 
stome (zoo/., bo f.). 

gynaecophoral groove, see gynaeco- 

gynaecophore (jine'kofor) . [Gk. 
gyne, woman ; pherein, to carry.] 
The canal or groove of certain 
Worms formed by an inrolling of 
the sides, in which the female is 
carried (zool.}. 

gynandrism (jman'drlzm) n. [Gk. 
gyne, woman ; aner, man.] Her- 

gynandromorphism (jinan'dromor'- 
fizm) n. [Gk. gyne, woman ; aner, 
man ; morphe, form.] Condition of 
having one side characteristically 
male, the other female, from ex- 
ternal aspect. 

gynandrophore ( jlnan'drofor') n. [Gk. 
gyne, woman ; aner, man ; pherein, 
to carry.] An axial prolongation 
bearing a sporophyll (oof.). 

gynandrosporous (jinan'drospo'rus) 
a. [Gk. gyne, woman ; aner, man ; 
sporos, seed.] With androspores 
adjoining the oogonium, as in some 
Algae (oof.). 

gynandrous (jinan'drus)a. \G\i.gyne, 
woman ; aner, man.] Having the 
stamens fused with the pistils, as in 
some Orchids (oof.). 

gynantherous (jinan'thgrus) a: [Gk. 
gyne, woman ; anf/ios, flower.] Hav- 
ing the stamens converted into pistils 

gynobase (ji'nobas) n. [Gk. gyne, 
woman ; L. basis, base.] A gynoe- 
cium-bearing receptacle of certain 

plants ; the condition in which the 
style appears to arise from the 
ovary (6of.). 

gynobasic style, a style arising from 
the base of the carpel (oof.). 

gynodioecious (jf nodle'shus) a. [Gk. 
gyne, woman ; dis, twice ; oikos, 
house.] Dimorphic, with some 
plants producing only female 
flowers (oof.). 

gynoecium (jine'stum) n. [Gk. gyne, 
woman ; oikos, house.] The pistils, 
carpels, or female organs of a flower 

gynogonidia (ji'ndgonld'ia) n. plu. 
[Gk. gyne, woman ; gonos, offspring.] 
Female sexual elements formed after 
repeated division of parthenogonidia 
in Mastigophora (oio/.). 

gynomonoecious (ji'nomone'shus) a. 
[Gk. gyne, woman ; monos, alone ; 
oikos, house.] Appl. plants with 
pistillate flowers only (oof.). 

gynophore (ji'nofor) n. [Gk. gyne, 
woman ; pherein, to carry.] A 
stalk supporting the ovary ; an 
elongation of the thalamus between 
stamens and pistil (oof.). 

gynostegium (jfnosce'jium) n. [Gk. 
gyne, woman ; stege, roof.] A pro- 
tective covering for a gynoecium 

gynostemium (ji'noste'mlum) . [Gk. 
gyne, woman ; stemon, warp.] The 
column composed of pistil and 
stamens in Orchids (oof.). 

gyration (jira'shun) n. [L. gyrare, to 
revolve.] Rotation, as of cells ; a 
whorl of a spiral shell (zool.}. 

gyrose (jfros) a. [L. gyrare, to 
revolve.] With undulating lines ; 
sinuous (dot.). 

gyrus (ji'rus) n., gyri (jl'rl) plu. [L. 
gyrus, circle.] A cerebral convolu- 
tion ; a ridge between two grooves 


habenula (habSn'Oli) n. [L. habena, 
strap.] A name appl. certain 
band-like structures (anaf.). 

habituation (hablt'ua'shun) n. [L. 
habituare, to bring into a habit.] 
The adjustment effected in a cell 
by which subsequent contacts of 




the same stimulus produce dim- 
inishing effects (phys.}. 

hadrocentrlc (h&d'rosgn'trik) a. [Gk. 
hadros, thick ; kentron, centre.] 
With the phloem surrounding the 
xylem (bot.}. 

haemachrome (he'makrom) n. [Gk. 
haima, blood ; chromos, colour.] 
The colouring matter found in the 
blood (phys.}. 

haemacyanin, see haemocyanin. 

haemacyte (he'masit) n. [Gk. haima, 
blood ; kytos, hollow.] A blood 
corpuscle (anat., phys.}. 

haemad (he'mad) adv. [Gk. haima, 
blood.] Situated on same side 
of vertebral column as the heart 
(zool., anat.}. 

haemal (he'mal) a. [Gk. haima, 
blood.] Pert, blood or blood- 
vessels ; also situated on the same 
side of the vertebral column as the 
heart (zool.}. 

haemamoeba (hem'ame'ba) n. [Gk. 
haima, blood ; amoibos, exchang- 
ing.] Protozoon with an amoeboid 
trophozoitic stage parasitic in a red 
blood-corpuscle (zool.}. 

haemapoietic (hem'apoigt'ik) a. [Gk. 
haima, blood ; poiein, to form.] 

haemapophysis (hem'apof'isis) n. 
[Gk. haima, blood ; apo, from ; 
phyein, to grow.] One of plate-like 
or spine-like processes growing 
from the latero-ventral surfaces of 
a vertebral centrum (anat.}. 

haexnatal (hem'atal) a. [Gk. haima, 
blood.] Pert, blood or blood-vessels. 

haematid (hem'atid) n. [Gk. haima, 
blood.] Red blood-corpuscle. 

haematin (hem'atln) n. [Gk. haima, 
blood.] A blue-black substance 
formed by the decomposition of 
haemoglobin, and probably con- 
taining iron (phys.}. 

haematobic (hem'ato'bflc) a. [Gk. 
haima, blood ; bios, life.] Living 
in the blood (zool.}. 

haematobium (hem'ato'bTum) n. [Gk. 
haima, blood ; bios, life.] Any or- 
ganism, plant or animal, living in 
the blood (biol.}. 

haematoblast (hgm'atoblast) n. [Gk. 
haima, blood ; blastos, bud.] Any 
cell that will develop into a red 
blood-corpuscle (emb.}. 

haematochrome (hgm'atokrom) n. 
[Gk. haima, blood ; chromos, colour.] 
A red colouring matter found in 
certain Algae (bot.}. 

haematocryal (hgm'atokrl'al) a. [Gk. 
haima, blood ; kryos, cold.] Cold- 
blooded (zool.}. 

haematocyanin (hgin'atosl'anTn) n. 
[Gk. haima, blood ; kyanos, dark 
blue substance.] A colourless sub- 
stance in the blood of Molluscs 
and Arthropods which becomes 
blue when oxydized (zool.}. 

haematocytozoon (hgm'atosi'tozo'on) 
n. [Gk. haima, blood ; kytos, hol- 
low ; zoon, animal.] An intra-cor- 
puscular blood parasite (zool.). 

haematodocha (hgm'atodo'ka) n. [Gk. 
haima, blood ; doche, receptacle.] 
A fibre-elastic bag, normally col- 
lapsed and spirally disposed round 
the base of the bulb, the basal 
portion of the palpal organ in the 
Araneae (zool.}. 

haematogen (hgm'atojen) n. [Gk. 
haima, blood ; gignesthai, to pro- 
duce.] A pseudo-nuclein containing 
iron (phys.}. 

haematogenesls (hgm'atojSn'esis) n. 
[Gk. haima, blood ; gignesthai, to 
produce.] The formation of blood 

haematogenous (hSm'atoj'gnus) a. 
[Gk. haima, blood ; gignesthai, to 
produce.] Formed in the blood 

haematoidln (hgm'atoid'In) n. [Gk. 
haima, blood ; eidos, resemblance.] 
An iron-free pigment found in 
blood-stains (phys.}. 

haematolysis (henYatSl'isis) n. [Gk. 
haima, blood ; lyein, to dissolve.] 
Breaking up of blood corpuscles, 
hence reduced coagulability (phys.}. 

haematophagous (hgm'atSf'agus) a. 
[Gk. haima, blood ; phagein, to eat.] 
Feeding on the blood, or obtaining 
nourishment from the blood (zool.}. 

haematophyte (hgm'atoflt) n. [Gk. 
haima, blood ; phyton, plant.] Any 
vegetable micro-organism of the 
blood (phys.}. 

haematoporphyrin (he"m'at6p6r'fir!n) 
n. [Gk. haima, blood ; porphyra, 
purple.] An iron-free substance 
formed by the decomposition of 
haematin (phys.}. 




haematosis (hem'ato'siTs) n. [Gk. 
haimafoein, to change to blood.] 
Blood-formation (phys.}. 

haeniatothermal (hgm'atothgr'mal) a. 
[Gk. haima, blood ; thermos, warm.] 
Warm-blooded (zool.). 

haematozoon (hgm'atb'zo'on) n. [Gk. 
haima, blood ; zoon, animal.] Any 
animal parasitic in the blood (zool.). 

haemic (hem'ik) a. [Gk. haima, 
blood.] Pert, blood (phys.). 

haemin (hem'in) n. [Gk. haima, 
blood.] Haematin hydrochloride 

haeinochromogen (hem'okro'mb'jen) 
n. [Gk. haima, blood ; chroma, 
colour ; gignesthai, to produce.] 
The colour producing component 
of haemoglobin (phys.). 

haemocoele (hem'osel) n. [Gk. haima, 
blood ; koilos, hollow.] An ex- 
panded portion of the blood system 
which replaces the true coelom 

haemocyanin (hern'osfanm), see 

haemocytolysis (hem'osltol'isis) n. 
[Gk. haima, blood ; kytos, hollow ; 
lyein, to dissolve.] The breaking 
up of the red blood-corpuscle by 
solution (phys.). 

haemocytotrypsis (hem'osl'totrip'sTs) 
n. [Gk. haima, blood ; kytos, hol- 
low ; tribein, to rub.] Breaking up 
of blood by pressure (phys.). 

haemoerythrin (hem'derith'rin) . 
[Gk. haima, blood ; erythros, red.] 
A red pigment found in the blood 
of Worms, etc., probably performing 
the same functions as haemoglobin 

haemoglobin (hem'oglo'bin) . [Gk. 
haima, blood ; globos, sphere.] The 
red colouring matter of blood 

haemoid (hem'oid) a. [Gk. haima, 
blood ; eidos, resemblance.] Re- 
sembling blood (phys.). 

haemolymph (hem'olimf) n. [Gk. 
haima, blood ; lympke, fluid.] A 
fluid found in the coelom of some 
invertebrates, which is regarded as 
equivalent to the blood and lymph 
of the higher forms (zool.). 

haemolysin (hern'oll'sln) . [Gk. 
haima, blood ; lyein, to dissolve.] 
A substance developed in the blood 

serum capable of destroying red 
blood-corpuscles (phys.}. 

haemolysis (hemol'lsTs), see haema- 

haemoplasmoclium (hem'oplasmo'- 
dium) n. [Gk. haima, blood , 
plasma, something moulded.] A 
unicellular animal parasite of the 
blood (zool.\ 

haemotropic (hem'otrop'ik) a. [Gk. 
haima, blood ; trepein, to turn.] 
Affecting or acting upon the blood 

haemozoin (he'mozo'In) n. [Gk. haima, 
blood ; zoon, animal.] Granules 
of a black pigment usually called 
melanin, but without the chemical 
characteristics of true melanin 

hair (har) n. [A.S. haer.] A thread- 
like or filamentous outgrowth of the 
epidermis of animals (zool.) ; any 
outgrowth of the epidermis consist- 
ing of one or more cells, and very 
varied in shape (tot.}. 

hair cell, any of the columnar cells 
bearing long stiff processes or hairs, 
found in the inner ear near the 
points of entrance of the nerve 
fibres (anat.). 

hair follicle, the tubular sheath 
formed by an invagination of the 
epidermis and surrounding the 
base of a hair (anat.}. 

hair worm, any of the small Nema- 
todes (zool.). 

half-inferior, having the ovary but 
partially adherent to the calyx 

half-terete, rounded on one side, 
flat on the other (&?/.). 

haliplankton (hal'fplang'kton) n. [Gk. 
hals, the sea ;plangklos, wandering.] 
The floating organisms in the sea ; 
cf. limnoplankton. 

hallux (hal'uks) n. [L. hallux, the 
great toe.] The first digit of the 
hind-limb (anat.}. 

halobios (hal'obfos) . [Gk. hals, 
sea ; bios, life.] The sum total of 
living plants and animals in the 
sea (biol.}. 

halolimnic (hal'olTm'nik) a. [Gk. 
hals, sea ; limne, marsh.] Pert, or 
referring to marine organisms 
modified to live in fresh water 




halophilous (halof'ilus) a. [Gk. hals, 
salt ; philein, to love.] Salt-loving 

halophyte (haloflt) n. [Gk. hals, 
salt ; phyton, plant.] Shore plants ; 
plants capable of thriving on salt- 
impregnated soils (dot.}. 

halteres (hal'terez) n. plu. [Gk. 
halter, weight used in jumping.] 
A pair of small capitate bodies 
representing the rudimentary pos- 
terior wings in Diptera, which are 
said to be balancers (zool.}. 

hamate (ham'at) a. [L. hamatus, 
hooked.] Hooked or hooked- 
shaped at the tip. 

hamatum (hama'tum) n. [L. hamatus, 
hooked.] The unciform bone in 
the carpus, probably corresponding 
to the fourth arid fifth distalia of a 
typical pentadactyl limb (zool.}. 

hamirostrate (ham'iros'trat) a. [L. 
hamus, hook ; rostrum, beak.] 
Having a hooked beak (zool.}. 

hamose (ha'mos) a. [L. hamus, hook.] 
Hooked (dot.}. 

hamular (ham'ular) a. [L. hamus, 
hook.] Hooked ; hook-like (zool.}. 

hamulus (ham'ulus) n. [L. hamulus, 
little hook.] A hook, or hook-like 
process (anat.} ; the minute hook- 
like process on the distal barbules 
which aid in the interlocking of the 
barbs of a feather (zool.}. 

hapaxanthous (hap'aksan'thus) a. 
[Gk. hapax, once ; anthos, flower.] 
With only a single flowering period 

haplocaulescent (hap'lokoles'ent) a. 
[Gk. haploos, simple ; L. caulis, 
stem.] With a simple axis, i.e., 
capable of producing seed on the 
main axis (tot.}, 

haplochlainydeous (hap'loklamid'eus) 
a. [Gk. haploos, simple ; chlamys, 
cloak.] Having rudimentary leaves 
in connection with the sporophylls 

haplodont (hap'lodont)tf. [G\a. haploos, 
simple ; odous, tooth.] Having the 
molars with simple crowns (zool.}. 

haploid (hap'loid) a. [Gk. kaploos, 
simple ; eidos, like.] Having the 
number of chromosomes character- 
istic of the germ-cells for the 
organism in question (biol.}. 

haploperistomous (hap'loperls'tomus) 

a. [Gk. haploos, simple ; peri, 
around ; stoma, mouth.] Having 
a peristome with a single row of 
teeth ; appl. Mosses (hot.}. 

haplopetalous (hap'lopet'alus) a. [Gk. 
haploos, simple ; petalon, petal.] 
With a single row of petals (bot.}. 

haptera (hap'tera) n. plu. [Gk. hap- 
tein, to fasten.] Special disc-like 
outgrowths from the stem - like 
portion of certain Algae, which 
serve as organs of attachment 

haptophores (hap'tof orz) n. plu. [Gk. 
haptein, to fasten ; pherein, to carry.] 
The combining qualities of the 
molecule of a toxin ; cf. toxophores 

harmonic suture, an articulation 
brought about by the apposition of 
fairly smooth edges or surfaces 

harmosone (har'moson) //. [Gk. 
armozo, I regulate.] One of the 
class of hormones which influence 
growth (phys.}. 

HassaH's concentric corpuscles, 
cell nests in the reticulum of the 
thymus gland (anat.). 

hastate (has'tat) a. [L. hasta, spear.] 
Spear-shaped, more or less tri- 
angular with the two basal lobes 
divergent (hot.}. 

haulm (horn) n. [A.S. healing The 
stem of such plants as peas ; the 
stem of a grass (bot.}. 

haustellate (hos'telat) a. [L. haurire, 
to suck.] Having a proboscis 
adapted for sucking (zool.}. 

haustellum(h6steTum) n. [L. haurire, 
to suck.] A proboscis adapted for 
sucking (zool.}. 

haustorial (hosto'rlal) a. [L. haurire, 
to drink.] Pert, or resembling a 
haustorium (bot.}. 

haustorium (hosto'riiim) n. [L. 
haurire, to drink.] An outgrowth 
of the stem of certain plants, which 
serves as a means of drawing food 
from the host plant (bot.}. 

haversian canals [ffavers, English 
physician], the small canals in 
bone in which the blood-vessels lie 

head (hed) n. [AS. heafod.] The 
anterior part of a vertebrate body 
containing the brain, skull, eyes, 




ears, etc. ; the anterior end of most 
invertebrate animals containing 
the cerebral ganglia ; the antlers of 
deer (zool.) ; the top of a plant when 
it consists of a mass of leaves ; a 
compact inflorescence (bot.). 

head case, the outer hard covering 
of an insect's head (zool.). 

head cell, one of the cells found on 
the manubrium of the antheridium 
of Chara (bot.). 

head kidney, the pronephric portion 
of the kidney, in vertebrates usually 
represented only in the embryo ; a 
nephridium usually developed in 
the cephalic segment of inverte- 
brates (zool.). 

heart (hart) n. [A.S. heorte."] A hollow 
muscular organ with a varying 
number of chambers which by 
rhythmic contraction keeps up the 
circulation of the blood (zool.,anat.) ; 
the core or central portion of a tree 
or fruit (bot.). 

heat (het) n. [A.S. haetu.] A kind 
of energy manifested in various 
ways ; the sensation of warmth 
produced by stimulation of special 
organs ; the period of sexual desire 

heat spot, any of the special areas 
on the skin at which nerve endings 
sensitive to heat are found (phys.). 

hectocotylus (heVtokot'llus) //. [Gk. 
hekaton, hundred ; kotyle, vessel.] 
One of the arms of a male ceph- 
alopod specialized to effect transfer- 
ence of sperms to eggs (zool.). 

hedonic (hedon'ik) glands, skin 
glands found in certain reptiles 
which secrete muskand are specially 
active at the rutting season. 

heel(hel). [A.S. Ae/a.] The hinder 
part of the foot ; the posterior 
tarsal portion of the foot ; the talon 
or talonid of a tooth (zool.). 

hekistotherm (hekTs'tothgrm) n. [Gk. 
hekistos, least ; therme, heat.] A 
plant that thrives with the minimum 
of heat, as alpine plants (bot.). 

helicine (heTisin) a. [Gk. helix, 
spiral.] Spiral ; convoluted ; 
hoisted ; appl. certain convoluted 
and dilated arteries in the penis ; 

4 pert, outer rim of the pinna (anat.). 

helicoid (heTikoid) a. [Gk. helix, 
spiral; eidos, like.] Spiral; shaped 

like a snail's shell ; pert, genus 
Helix (zool.) ; pert, type of sym- 
podial branching in which the sym- 
podium consists of the fork branches 
of the same side (bot.). 

helicoid cyme, an inflorescence pro- 
duced by the suppression of the 
successive axes on the same side, 
thus causing the sympodium to be 
spirally twisted (bot.). 

helicotrema (hel'ikotre'ma) n. [Gk. 
helix, spiral ; trema, hole.] A 
small opening near the summit 
of the cochlea by which the two 
scalae communicate with one 
another (anat.). 

heliosis (helio'sTs) n. [Gk, Julias, 
sun.] The production of dis- 
coloured spots or markings on 
leaves through the concentration 
of the sun on them (bot.). 

heliotaxis (he'liotak'sis) n. [Gk. 
helios, sun ; taxis, arrangement.] 
Response to the stimulus of the 
sun's rays. 

heliotropism (he'liot'ropizm) n. [Gk. 
helios, sun ; trepein, to turn.] The 
tendency of growing organisms 
or parts thereof to respond to 
the stimulus of sunlight (biol.). 

helix (he'llks) n. [Gk. helix, spiral.] 
The outer rim of the ear (anat.) ; 
the coiled spiral arrangement of 
certain structures in the inverte- 
brates (zool.). 

helmet (heTme't) n. [O.F. helmet, 
head covering.] The process of 
the bill of hornbills ; the bony 
plates covering the head of certain 
extinct Fishes ; the galea of Insects 

helminthology (hel'minthol'dji) n. 
[Gk. helmins, worm ; logos, dis- 
course.] The study of the natural 
history, anatomy, etc., of Worms, 
especially parasitic forms (zool.). 

helotism (hel'otizm) . [Gk. Helos, 
Laconian town.] Symbiosis in 
which the one organism enslaves 
the other and forces it to labour 
in its behalf, e.g. in Lichens, in 
some species of ants (biol.). 

hemelytron (hemeTitron) n. [Gk. 
hemi, half; elytron, wing.] The 
thickened forewing of certain 
Insects ; the elytra of certain 
Worms (zool.). 




hemelytrum, hemelytron. 

hemibasidium (hem'ibasid'ium) n. 
[Gk. hemi, half ; basis, base.] The 
promycelium of the Ustilaginales 

hemibathybial (hem'ibathib'ial) a. 
[Gk. hemi, half; bathys, depths.] 
Perl, plankton between the littoral 
and bathybial zones (biol.). 

hemibranch (hem'ibrangk) n. [Gk. 
hemi, half; brangchia, gills.] A 
gill with gill filaments on one side 
only (zool.). 

hemichordate (hem'ikor'dat) a. [Gk. 
hemi, half; chorde, string.] Possess- 
ing a more or less rudimentary 
notochord (zool.). 

hemicyclic (hem'isi'klik) a. [Gk. 
hemi, half; kyklos, round.] With 
some of the floral whorls cyclic, 
others spiral (bot.). 

hemielytron, hemelytron . 

hemiepiphyte (hem'iep'iflt) n. [Gk. 
hemi, half ; epi, upon ; phyton, 
plant.] A plant whose seeds 
germinate on another plant, but 
later send roots to the ground 

hemignathous (hem'ignath'us) a. [Gk. 
hemi, half ; gnathos, jaw.] Having 
one jaw snorter than the other, as 
in some birds (zool.). 

hemlmetabolic (hgm'imgt'aborik) a. 
[Gk. hemi, half; meta, after; ballein, 
to change.] Having an incomplete 
metamorphosis, i.e. the larva has a 
strong resemblance to the adult 

hemiparasitic (hem'ipar'asTt'ik) a. 
[Gk. hemi, half; para, beside; 
sites, food.] Pert, a plant which 
is capable of carrying on photo- 
synthesis, but not sufficiently to 
supply all food material (bot.). 

hemipenis (hem'ipe'nis) n. [Gk. hemi, 
half; L. penis, penis.] One of the 
paired copulatory organs in lizards 
and snakes (zool.). 

hemipterous (hemip'terus) a. [Gk. 
hemi, half; pteron, wing.] Pert. 
Hemiptera (zool.). 

hemisaprophyte (hgm'isap'roflt) n. 
[Gk. hemi, half ; sapros, dung ; 
phyton, plant.] A plant living 
partly by photosynthesis, partly 
by obtaining food from the humus 

heinisome (hSm'isom) n. [Gk. hemi, 
half; soma, body.] The sym- 
metrical half of an animal about 
a median vertical plane (zool.). 

hemisphere (he'm'isfer) n. [Gk. 
hemi, half; sphaira, globe.] One 
of the cerebral hemispheres (zool.). 

hemisystole (hgm'isis'tole) n. [Gk. 
hemi, half ; syn, with ; stellein, to 
set.] Contraction of one ventricle 
of the heart (phys.). 

hemitropous (hemit'ropus) a. [Gk. 
hemi, half; trepein, to turn.] 
Turned half round, having an 
ovule with the hilum on one side 
and the micropyle, etc., opposite 
in a plane parallel to the placenta 

hemorrhoidal (hem'oroi'dal) a. [Gk. 
haima, blood ; rhein, to flow.] 
Rectal ; appl. arteries and veins 

Henle's layer, a single stratum of 
nucleated cubical cells in the inner 
root sheath of a hair follicle (anat.). 

Henle's loop, the loop of a kidney 
tubule within the apical portion of 
the pyramid (anat.). 

hepar (he'par) n. [L. hepar, liver.] 
Liver or any organ having a similar 
function (anat., zool.). 

hepatic (hepat'ik) a. [L. hepar, liver.] 
Pert, like or associated with the 
liver (zool.) ; pert. Hepatics (bot.). 

hepatocolic (hep'atokol'ik) a. [L. 
hepar, liver ; colon, large intestine.] 
Pert, liver and colon (zool.). 

hepatocystic (hgp'atosis'tik) a. [L. 
hepar, liver ; Gk. kystis, bladder.] 
Pert, liver and gall-bladder (zool.). 

hepatoduodenal (hep'atodu'tide'nal) a. 
[L. hepar, liver ; duodeni, twelve 
each.] Pert, liver and duodenum 

hepatoenteric (hgp'atoenter'lk) a. [L. 
hepar, liver ; Gk. enteron, gut.] Of 
or pert, liver and intestine. 

hepatogastric (hep'atogas'trik) a. [L. 
hepar, liver ; Gk. gaster, belly.] 
Pert, liver and stomach (anat.). 

hepatopancreas, the digestive gland 
in many invertebrates, supposed to 
perform a function similar to that 
of the liver and of the pancreas in 
higher forms (zool.). 

hepatoportal (hep'atdpor'tal) a. [L. 
, liver ; portare, to carry.] 




Pert. or designating the portal 
circulation of the liver (zoo/.). 

hepatorenal (hep'atore'nal) a. [L. 
hepar, liver ; rents, kidneys.] Pert. 
liver and kidney (zoo/.). 

hepatoumbilical (hepatoumbil'ikal) 
a. [L. hepar, liver ; umbo, umbo.] 
Joining liver and umbilicus (anat.). 

heptagynous (hgptaj'inus) a. [Gk. 
hepta, seven ; gyne, female.] With 
seven pistils (oof.}. 

heptamerous (heptam'Srus) a. [Gk. 
hepfa, seven ; meros, part.] Having 
the whorls of the flower in sevens 

heptandrous (hSptan'driis) a. [Gk. 
hepta, seven ; aner, man.] Having 
seven stamens (bot.}. 

heptastichous (heptas'tikus) a. [Gk. 
hepta, seven ; stichos, row.] Having 
the leaves arranged in sevens 

herb (h6rb) n. [M.E. herbe.] Any 
seed plant which has not a woody 
stem (bot.). 

herbaceous (herba'shiis) a. [L. her- 
baceus, grassy.] Pert, or resem- 
bling a herb, or similarly formed 

hercogamy (hgrkog'ami) n. [Gk. 
herkos, barrier ; gamos, birth.] The 
condition in which self-fertilization 
is impossible (bot.}. 

hereditary (hergd'itari) a. [L. hered- 
itas, heirship.] Transmitted or 
possibly transmissible from parent 
to offspring, as a special quality or 
condition (biol.). 

heredity (hered'iti) n. [L. hereditas, 
heirship.] The organic relation 
between successive generations 

hermaphrodite (hermaf'rodlt) n. [Gk. 
hcrmaphroditos, combining both 
sexes.] Any organism having both 
male and female reproductive 
organs (biol.}. 

hermaphroditism (hermafrod'Itizm) n. 
[Gk. hermaphrodites, combiningboth 
sexes.] The condition of having 
both male and female reproductive 
organs in one individual (biol.}. 

herpetology (h6r'p6tol'oji) n. [Gk. 
herpeton, reptile ; logos, discourse.] 
That part of zoology dealing with 
the structure, habits and classifica- 
tion of Reptiles (zoo/.). 

hesperidium (hgs'perid'Ium) n. [Gk. 
Hesfieria, Western land.] A superior, 
many-celled, few-seeded indehiscent 
fruit, having epicarp and mesocarp 
joined together, and an endocarp 
projecting into the interior as mem- 
branous partitions which divide the 
pulp into chambers (oof.). 

heteracanthous (het'erakan'thus) a. 
[Gk. heteros, other ; akanthe, spine.] 
Having the spines in the dorsal fin 
asymmetrical (zoo/.). 

heteractinal (hgt'erak'tlnal) a. [Gk. 
heteros, other ; aktis, ray.] Pert. 
nail-like spicules, having a disc of 
six to eight rays in one plane, and 
a stout ray rising at right angles to 
these (zoo/.). 

heterandrous (het'eran'drus) a. [Gk. 
heteros, other ; aner, man.] With 
the stamens of different lengths or 
shape (bot.). 

heterauxesis (hgt'erokse'sis) n. [Gk. 
heteros, other ; auxein, to grow.] 
Irregular or asymmetrical growth 
of organs (bot.}. 

heteraxial (het'erak'slal) a. [Gk. 
heteros, other ; axis, axis.] With 
three unequal axes (zoo/.). 

heteroblastic (hgt'eroblas'tik) a. [Gk. 
heteros, other ; blastos, bud.] With 
an indirect development (zoo/.). 

heterocarpous (heYgrokar'pus) a. 
[Gk. heteros, other ; karpos, fruit.] 
Bearing two distinct types of fruit 

heterocellular (heYerosel'ular) a. [Gk. 
heteros, other ; L. cellula, cell.] 
Composed of more than one type of 
cells (bot.). 

a. [Gk. heteros, other ; kephalc, 
head.] Having the pistillate flowers 
on separate headsfromthestaminate 
flowers (bot.}. 

heterocercal (het'eroser'kal) a. [Gk. 
heteros, other ; kerkos, tail.] Hav- 
ing the vertebral column terminat- 
ing in the upper lobe of the fin, 
which is usually larger than the 
lower ; afipl. tail fins (zoo/.). 

heterocercy (het'groseVs!) . [Gk. 
heteros, other ; kerkos, tail] The 
condition of having a heterocercal 
tail (zoo/.). 

heterochlamydeous (heYgroklamld'- 
eus)#. [Gk. heteros, other ; chlamys^ 




cloak.] Having a calyx differing 
from corolla in colour, texture, etc. 

heterochromous (heYerokro'mus) a. 
[Gk. heteros, other ; chroma, colour.] 
Having disc and marginal florets 
differently coloured (bot.). 
heterochronism (hgt'erokro'nizm) n. 
[Gk. heteros, other ; chronos, time.] 
A departure from the typical se- 
quence in time of the formation of 
the organs (biol.). 

heterochrosis (h6t'6rokr5'sis) n. [Gk. 
heteros, other ; chrosis, colouring.] 
Abnormal coloration (zool.). 
heteroclinous (heYgrokll'nus) a. [Gk. 
heteros, other ; kline, bed.] Hetero- 
cephalous (bot.). 

heterocoelous (het'grose'lus) a. [Gk. 
heteros, other ; koilos, hollow.] Pert. 
vertebrae with saddle-shapedarticu- 
latory centra (zool.). 
heterocysts (hgt'groststs) n. plu. [Gk. 
heteros, other ; kystis, bladder.] The 
clear cells occurring at intervals 
on the filaments of certain Algae, 
and marking the limits of the 
hormogonia (bot.). 

heterodactylous (het'erodak'tilus) a. 
[Gk. heteros, other ; daktylos, toe.] 
With the first and second toes 
turned backwards (zool.). 
heterodont (het'erodont) a. [Gk. 
heteros, other ; odous, tooth.] Hav- 
ing the teeth differentiated for 
various purposes (zool). 
heterodromous (he't'e'rod'romus) a. 
[Gk. heteros, other ; dromein, to 
run.] Having the genetic spiral 
of the stem leaves turning in a 
different direction to that of the 
branch leaves (bot.). 
heteroecious (het'gre'shus) a. [Gk. 
heteros, other; oikos, house.] Pass- 
ing different stages of its life on 
different hosts (bot.). 
heterogamous (heYerog'amus) a. [Gk. 
heteros, other ; gamos, marriage.] 
With unlike gametes ; having two 
types of flowers ; having indirect 
pollination methods (biol.). 
heterogamy (hgt'grog'aml) a. [Gk. 
heteros, other ; gamos, offspring.] 
Alternation of generations (biol.). 
heterogangliate (hgt'grogang'gltat) 
a. [Gk. heteros, other ; gangglion, 
ganglion.] With widely separated 

and asymmetrically placed nerve- 
ganglia (zool.). 

heterogenesis (het'erqje'n'e'sis) n. [Gk. 
heteros, other ; gignesthai, to pro- 
duce.] Spontaneous generation ; 
alternation of generations (biol.). 

heterogeny (heVerqj'eni) n. [Gk. 
heteros, other ; genos, race.] Hav- 
ing several distinct generations 
succeeding one another in a 
regular series (biol.). 

heterogonous (het'erog'onus) a. [Gk. 
heteros, other ; gonos, birth.] Pert. 
heterogenesis (biol.). 

heterogony (het'erog'oni) n. [Gk. 
heteros, other ; gonos, birth.] Hav- 
ing two kinds of flowers differing 
in length of stamen (bot.) ; alterna- 
tion of generations (biol.). 

heterogynous (het'eroj'mus) a. [Gk. 
heteros, other ; gyne, woman.] 
With two types of females (zool.). 

heterokaryote (het'erokar'Iot) a. [Gk. 
heteros, other ; karyon, nut.] Hav- 
ing two distinct types of nuclei 

heterokinesis (het'erokme'sis) n. [Gk. 
heteros, other ; kinein, to move.] 
Qualitative or differential division 
of the chromosomes (biol.). 

heterolecithal (het'eroles'ithal) a. 
[Gk. heteros, other ; lekithos, yolk.] 
Havingunequally distributed deuto- 
plasm (biol.). 

heterology (het'erol'qjl) n. [Gk. 
heteros, other ; logos, discourse.] 
The non-correspondence of parts 
owing to different origin or different 
elements (biol.). 

heteromallous (het'erom'alus) a. [Gk. 
heteros, other; mallos, lock of wool.] 
Spreading in different directions 

heteromastigate (hgt'e'romas'tigat) a. 

eik. heteros, other ; mastix, lash.] 
aving two different types of 
flagella (zool.). 

heteromastigote (het'eromas'tigot), 

heteromerous (het'erom'erus) a. [Gk. 
heteros, other ; meros, part.] Hav- 
ing the whorls consisting of 
an unequal number of parts (bot.). 

heterometabolic (het'eromeYabol'ik) 
a. [Gk. heteros, other ; metabole, 
change.] Having incomplete meta- 
morphosis (zool.). 




heteromorphic (het'eromor'flk) a. 
[Gk. heteros, other ; morphe, shape.] 
Having different forms at different 
times (zool.). 

heteromorphism (heYSromor'fizm) n. 
[Gk. heteros, other ; morphe, shape.] 
The state or quality of being 
heteromorphic (biol.). 
heteromorphosis (heYeromor'fosis) n. 
[Gk. heteros, other; morphe, shape.] 
The production of a part in an 
abnormal position, by any organ- 
ism ; a case of regeneration, when 
the new part is different from that 
removed (biol.). 

heteromorphous (hfit'e'romor'fus) a. 

[Gk. heteros, other; morphe, shape.] 

Pert, an irregular structure, or 

departure from the normal (biol.). 

heteronereis (het'e'rone'reis) n. [Gk. 

heteros, other ; nereis, nereis.] A 

free-swimming dimorphic sexual 

stage of Nereis and other marine 

worms (zool.}. 

heteronomous (hgt'gron'omus) a. [Gk. 
heferos, other; nomos, law.] Subject 
to different laws of growth; special- 
ized on different lines (biol.). 
heteropelmous (heYeropeTmus) a. 
[Gk. heteros, other ; pelma, sole of 
foot.] Having the flexor tendons 
of the toes bifid (zool.). 
heteropetalous (heYgropeYalus) a. 
[Gk. heteros, other ; petalon, petal.] 
With dissimilar petals (bot.). 
heterophagous (hgt'eWagus) a. [Gk. 
heferos, other ; phagein, to eat.] 
Having young which are immature 
and require feeding at birth ; appl. 
birds (zool.). 

heterophyadic (hgt'eroflad'ik) a. [Gk. 
heteros, other ; phyas, shoot.] Pro- 
ducing separate shoots, one vegeta- 
tive, one reproductive (bot.). 
heterophyllous (het'grofil'us) a. [Gk. 
heteros, other; phyllon, leaf.] Bear- 
ing foliage leaves of different shape 
on different parts of the plant (bot.). 
heteroplasia (heYgropla'zia) n. [Gk. 
heteros, other ; plassein, to mould.] 
The development of one tissue 
from another of a different kind 

heteroplasm (het'Sroplazm) n. [Gk. 
heteros, other ; plasma, something 
moulded.] Tissue formed in ab- 
normal places (biol.). 

heteroproteose (heYeropro'teos) n. 
[Gk. heteros, other ; protos, first.] 
One of the primary products formed 
by the action of gastric juices on 
proteids (phys.). 

heterorhizal (het'grorl'zal) a. [Gk. 
heteros, other ; rhiza, root.] With 
roots coming from no determinate 
point (bot.). 

heterosporous (hSt'Stospo'riis, het'- 
SrSs'poriis) a. [Gk. heteros, other ; 
sporos, seed.] Producing two kinds 
of spores (bot.). 

heterosteinonous (hCt'erostem'onus) 
a. [Gk. heteros, other ; stemon, 
stamen.] With unlike stamens 

heterostrophy (het'eros'trofi) n. [Gk. 
heteros, other ; strophe, turning.] 
The condition of being coiled in 
a direction opposite to the normal 

heterostyled (het'erdstl'ld) a. [Gk. 
heteros, other ; stylos, pillar.] 
Having unlike styles ; or unequal 
styles (bot.). 

heterostyly (he't'e'rosti'li) n. [Gk. 
heteros, other; stylos, pillar.] Con- 
dition of being heterostyled (bot.). 

heterotaxls (heYgrotak'sis) n. [Gk. 
heteros, other ; taxis, arrangement.] 
Abnormal or unusual arrangement 
of organs or parts (biol.). 

heterotomy (heYgrot'oml) n. [Gk. 
heteros, other; temnein, to cut.] The 
condition of having the parts of the 
perianth whorls unequal or dis- 
similar (bot.) ; irregular dichotomy 
in Crinoids (zool.). 

heterotopy (heYerot'opi) n. [Gk. 
heteros, other ; topos, place.] Dis- 
placement (biol.). 

heterotrlchous (hgt'erot'rlkus) a. 

Eik. heteros, other ; thrix, hair.] 
aving two types of cilia (zool.). 

heterotrophic (het'erotrof'ik) a. [Gk. 
heteros, other ; trephein, to nourish.] 
Getting its nourishment from 
outside ; appl. parasitic plants 

heterotropic, heterotropous. 

heterotropous (he't'e'rot'ropus) a. [Gk. 
heteros, other ; trepein, to turn.] 
Pert, an ovule with hilum and 
micropyle at opposite ends in a 
plane parallel to the placenta (bot.). 

heterotypic (hgt'grotlp'Ik) a. [Gk. 





heteroS) other ; L. typus, type.] 
Pert, mitotic division in which the 
daughter chromosomes remain 
united and form rings (biol.). 

heteroxenous (het'erok'senus) a. [Gk. 
heteros, other ; xenos, guest.] Oc- 
curring on or infesting more than 
one kind of host (biol.). 

heterozygosis (het'erozlgo'sis) n. [Gk. 
heteros, other ; zygein, to yoke.] 
Condition or state of being hetero- 
zygote (dial.). 

heterozygote (het'erozl'got) n. [Gk. 
heteros, other ; zygein, to yoke.] 
A mendelian hybrid which contains 
one or more recessive characters 
and therefore does not breed true 

hexacanth (hek'sakanth) a. [Gk. 
hex, six ; akantha, thorn.] Having 
six hooks ; appl. embryos of flat- 
worms (zool.). 

hexactinal (hek'sak'tinal) a. [Gk. 
hex, six ; aktis, ray.] Pert, spicules 
with six rays (zool.). 

hexactine (hek'sak'tin) n. [Gk. hex, 
six ; aktis, ray.] A spicule with 
six equal and similar rays meeting 
at right angles (zool.). 

hexactinian (hek'saktm'Ian) a. [Gk. 
hex, six ; aktis, ray.] With the ten- 
tacles or mesenteries in multiples 
of six (zool.). 

hexacyclic (hek'sasi'kllk) a. [Gk. 
hex, six ; kyklos, circle.] Having 
the floral whorls consisting of six 
parts (bot.). 

hexagynous (heksaj'mus) a. [Gk. 
hex, six ; gyne, woman.] Having 
six pistils (bot.). 

hexamerous (hgksam'erus) a. [Gk. 
hex, six ; nteros, part.] Occurring 
in sixes or arranged in sixes 

hexandrous (heksan'drus) a. [Gk. 
hex, six ; aner, man.] Having six 
stamens (bot.). 

hexapetaloid (hek'sapgt'aloid) a. 
[Gk. hex, six ; pe talon, petal ; eidos, 
like.] With a petaloid perianth of 
six parts (bot.). 

hexapetalous (hek'sapet'alus) a. 
[Gk. hex, six ; petalon, petal.] 
Having six petals (bot.). 

hexaphyllous (hgk'safil'us) a. [Gk. 
hex, six ; phyllon, leaf.] Having 
six leaves (bot.). 

hexapod (hek'sapod) a. [Gk. hex, 
six ; pous, foot.] Pert, animal 
with six legs (zool.). 

hexapterous (heksap'terus) a. [Gk. 
hex, six ; pteron, wing.] Having 
six wing-like processes or ex- 
pansions (bot.). 

hexarch (hek'sark) a. [Gk. hex, six ; 
arche, beginning.] Having six 
radiating vascular strands ; appl. 
roots (bot.). 

hexasepalous (hek'sasep'alus) a. 
[Gk. hex, six ; sepalon, sepal.] 
Having six sepals (bot.). 

hexaspermous (hek'sasper'mus) a. 
[Gk. hex, six ; sperma, seed.] 
Having six seeds (bot.). 

hexastemonous (hek'sastem'onus) a. 
[Gk. hex, six ; stemon, stamen.] 
Having six stamens (hot.). 

hexaster (heksas'te'r) n. [Gk. hex, 
six ; aster, star.] A variety of the 
hexactine in which the rays branch 
and produce star-shaped figures 

hexastichous (heksas'tfkus) a. [Gk. 
hex, six ; stichos, row.] Having 
the parts arranged in six rows 

hexicology (hek'sikol'ojl) n. [Gk. 
hexis, habit ; logos, discourse.] 
Bionomics (biol.). 

hiatus (hia'tus) n. [L. hiare, to gape.] 
Any large opening (anat.). 

hibernaculum (hi bernak'ulum) n. 
[L. hibernaculum, winter resi- 
dence.] Specially modified winter 
bud, found in certain fresh-water 
Polyzoa (zool.). 

hibernate (hi'bernat) v. [L. hibemus, 
wintry.] To pass the winter in a 
resting state (biol.). 

hibernating glands, lymph glands 
of richly vascularized fatty tissue 
occurring in some Rodents and 
Insectivores (anat.). 

hidrosis (hldro'sis) n. [Gk. hidros, 
sweat.] Excretion of sweat ; per- 
spiration (phys.). 

high (hi) a. [A.S. heh.~] Having a 
more complex and more highly 
differentiated structure. 

hiliferous (hllif'grus) a. [L. hilum, 
trifle ; ferre, to carry.] Having a 
hilum (bot.). 

hilum (hl'liim) n. [L. hilum, trifle.] 
The scar on the ovule where it 




was attached to the placenta ; the 
eye of a seed ; the nucleus of a 
starch grain (hot.). 

hilus (hl'lCis) ;/. [L. hilum, trifle.] 
A small notch or opening ; a 
small opening or depression 
usually where the blood-vessels, 
etc., enter (anaf., zool.}. 

hind brain, the rhombencephalon, 
that portion of the brain derived 
from the third embryonic vesicle 

hind gut, a diverticulum of the yolk- 
sac extending into the tail-fold in 
the human embryo ; the posterior 
portion of the alimentary tract 

hinge joint, a joint in which the ar- 
ticulatory surfaces are so moulded 
to one another as to permit motion 
in one direction only (anaf.). 

hinge ligament, the tough elastic 
substance joining the two valves 
of a bivalve shell (zool.). 

hinge line, the line of articulation 
of the two valves in a bivalve shell 

hinge tooth, one of the projections 
found on the hinge line in bivalves 

hip-joint, the ball-and-socket joint 
between femur and hip-girdle 

hippocampal (hip'okam'pal) a. [Gk. 
hippos, horse ; kampos, sea-monster.] 
Pert, the hippocampus (anaf.). 

hippocampus (hip'okam'pus) n. [Gk. 
hippos, horse; kampos, sea-monster.] 
A curved eminence that extends 
throughout the entire length of the 
floor of the inferior cornu of the 
lateral ventricle (anaf.). 

hirsute (heVsut) a. [L. hirsutus, 
hairy.] Covered with hair-like 
feathers, appl. birds ; having stiff, 
hairy bristles (zool.} ; having stiff, 
hairy covering (hot.}. 

hirudin (hiru'din) n. [L. hirudo, 
leech.] A substance obtained in 
solution from the head of leeches 
which renders drawn blood non- 
coagulable ; an anticoagulin (phys.). 

hispid (his'pid) a. [L. hispidus, 
rough.] Having stiff hairs, spines, 
or bristles (hot., zool.}. 

histoblast (hls'toblast) n. [Gk. histos, 
tissue ; blastos, bud.] One of the 

units of any tissue (anaf.) ; imaginal 
discs (zool.}. 

histochemistry (his'tokgm'IstrT) n. 
[Gk. histos, tissue ; cheinos, juice.] 
The chemistry of animal tissues 

hlstocyte (his'toslt) n. [Gk. histos, 
tissue ; kytos, hollow.] A tissue 
cell as distinguished from a germ 
cell (zool.}. 

histogenesis (his'tojen'e'sis) n. [Gk. 
histos, tissue ; gigiiesthai, to pro- 
duce.] Formation and develop- 
ment of tissue (biol.). 

histogenic (hls'tqje'n'ik) a. [Gk. 
histos, tissue ; gignesthai, to pro- 
duce.] Tissue-producing ; appl. 
the separate merismatic layers in 
a stratified growing point (hot.} ; 
tissue-producing (zool.). 

histohaematin (his'tohe'matin) n. 

gik. histos, tissue ; haima, blood.] 
ne of the animal pigments with 
a great affinity for oxygen, and 
so supposed to be respiratory 

histology (histol'ojl) n. [Gk. histos, 
tissue ; logos, discourse.] The 
science which treats of the minute 
structure of tissues (biol.}. 

histolysis (Mstol'isTs) n. [Gk. histos, 
tissue ; lyein, to dissolve.] The 
dissolution of organic tissues 
(biol.} ; that process by which 
most of the pupal internal organs 
dissolve into a creamy fluid, 
except certain cells round which 
the new imaginal tissues are 
formed (zool.}. 

histone (his'ton) n. [Gk. histos, 
tissue.] An albuminose body de- 
rived from nucleo-histone (phys.}. 

histophyly (histof'ili) n. [Gk. histos, 
tissue ; phyle, tribe.] The phylo- 
genetic history of any group of 
cells (biol.}. 

histotrophic (his'totrof'lk) a. [Gk. 
histos, tissue ; trephein, to nourish.] 
Pert, or connected with tissue 
formation (phys.). 

histozoic (his'tozo'ik) a. [Gk. histos, 
tissue ; zoon, animal.] Living 
within tissues ; appl. trophozoitic 
stage of certain Sporozoa (zool.}. 

histozyme (his'tozlm) n. [Gk. histos, 
tissue ; zyme, leaven.] An enzyme 
found in the kidneys of certain 




animals capable of decomposing 

hippuric acid (phys.}. 
hoch (hSk) n. [A.S. hoh, heel.] The 

tarsal joint, or the region of the 

tarsal joint (zool.}. 
holarctic (holark'tik) a. [Gk. holos, 

whole ; arktos, bear.] Pert, species 

found in a zoogeographical region 

including the northern parts of the 

new and old worlds (zool.}. 
holaspldean (hol'aspid'ean) a. [Gk. 

holos, whole ; aspis, shield.] With 

a single series of large scales on 

the posterior aspect of the tarso- 

metatarsus (zool.}. 
holcodont (hol'kodont) a. [Gk. holkos, 

furrow ; odous, tooth.] Having the 

teeth in a long continuous groove 

holdfast, the sucker or disc on the 

thallus of certain Algae (bot.}. 
holobenthic (hol'obgn'thik) a. [Gk. 

holos, . whole ; benthos, depths.] 

Living in the depths of the sea 

throughout life (zool.}. 
holoblastic (hol'oblas'tik) a. [Gk. 

holos, whole ; blastos, bud.] Pert. 

eggs in which the cleavage is 

total (emb.}. 
holobranch (hol'obrangk) n. [Gk. 

holos, w 

vhole ; brangchia, gills.] A 
which gill filaments are 
borne on both sides (zool.}. 

holochlamydate (hol'oklam'idat) a. 
[Gk. holos, whole ; chlamys, cloak.] 
Having no notch on the margin of 
the mantle (zool.}. 

holochroal (hol'okro'&l) a. [Gk. holos, 
whole ; chros, touch.] Having eyes 
with globular or biconvex lenses 
closely crowded together, so that 
the cornea is continuous over the 
whole eye (zool.}. 

hologastrula (hol'ogas'troola) n. [Gk. 
holos, whole ; gaster, stomach.] A 
gastrula formed from a holoblastic 
egg (emb.}. 

holognathous (hordgnath'us) a. [Gk. 
holos, whole ; gnathos, jaw.] Hav- 
ing the jaw in a single piece 

holomastigote (hSl'omas'tigot) a. 
[Gk. holos, whole ; mastix, whip.] 
Having one type of flagellum 
scattered evenly over the body 

holometabolic (hol'dmeYabol'Ik) a. 

[Gk. holos, whole ; meta, after ; 
ballein, to change.] Having com- 
plete metamorphosis (zool.}. 

holometabolism (horometab'oWzm) n. 
[Gk. holos, whole ; metabole, change.] 
State of having complete metamor- 
phosis (zool.}. 

holomorphosis (hol'dmor'fdsis) n. 
[Gk. holos, whole ; morphe, shape.] 
Regeneration in which the entire 
part is replaced (zool.}. 

holonephros (hol'onef'ros) n. [Gk. 
holos, whole ; nephros, kidney.] 
The hypothetical continuous ex- 
cretory organ (anat.}. 

holophytlc (hol'ofit'ik) a. [Gk. holos, 
whole ; phyton, plant.] Obtaining 
the whole of its food after the 
manner of a plant (zool.}. 

holoplanktonic (hol'oplangkton'Tk) 
a. [Gk. holos, whole ; plangktos, 
wandering.]. Living near the 
surface throughout life (zool.}. 

holoptic (holop'tik) a. [Gk. holos, 
whole ; ops, eye.] Having the 
eyes of the two sides meeting in 
a coadapted line of union (zool.}. 

holorhinal (hol'drl'nal) a. [Gk. holos, 
whole ; rhis, nose.] Having nares 
with the posterior margin rounded, 
not cleft (zool.}. 

holoschisis (holos'kisis) n. [Gk. 
holos, whole ; schizein, to cut.] 
Amitosis (emb.}. 

holosericeous (hol'oserish'us) a. [Gk. 
holos, whole ; L. serious, silken.] 
Completely covered with silky 
hair-like structures (bot.) ; having 
a silky lustre or sheen (zool.}. 

holostomatous (hordstom'atiis) a. 
[Gk. holos, whole ; stoma, mouth.] 
With the margin of the aperture 
entire (zool.}. 

holosystolic (hol'osis'tolik) a. [Gk. 
holos, whole ; systole, contraction.] 
Pert, the complete systole (phys.}. 

holotrichous (holot'rikus) a. [Gk. 
holos, whole ; thrix, hair.] Having 
a uniform covering of cilia over 
the body (zool.}. 

holozoic (hol'6z5'ik) a. [Gk. holos, 
whole ; zoon, animal.] Obtaining 
the whole of its food after the 
manner of animals ; ingulfing pro- 
teids (zool.}. 

homacanth (hSm'Sk&nth) a. [Gk. 
homos, like ; akantha, spine.] 




Having the spines of the dorsal 
fin symmetrical (zool.). 

hoinaxon (hom'aksSn) a. [Gk. homos, 
alike ; axon, axis.] Built up around 
equal axes (zoo/.). 

homaxonlc, homaxon. 

homeoklnesis (hom'eokine'sis) n. 
[Gk. homoios, same ; kinein, to 
move.] Mitosis with an equal 
division of the chromatinic ele- 
ments to the daughter nuclei 

homeotely (ho'meot'gli) n. [Gk. 
homoios, same ; telos, end.] Evolu- 
tion from homologous parts, but 
with less close resemblance (biol.). 

hoineozoic (hom'eozo'lk) a. [Gk. 
homoios, same ; zoon, animal.] 
Pert, a region or a series of 
regions with identical fauna or 
flora (biol.). 

homoblastic (hom'oblas'tlk) a. [Gk. 
homos, alike; blastos, bud.] Hav- 
ing direct embryonic develop- 
ment ; arising from similar cells 

homocarpous (hom'okar'pus) a. [Gk. 
homos, alike ; karpos, fruit.] Bear- 
ing one kind of fruit (tot.). 

homocercal (horn'oseVkal) a. [Gk. 
homos, same ; kerkos, tail.] Having 
a tail with equal or nearly equal 
lobes, and axis ending near the 
middle of the base ; usually this 
type is derived from the hetero- 
cercal type (zool.). 

homocerebrin (horn'oseYSbrin) n. 
[Gk. homos, alike ; L. cerebrum, 
brain.] A substance identical 
with cerebrin (phys.). 

homochlamydeous (hom'oklamld'- 
eus) a. [Gk. homos, same ; 
chlamys, cloak.] Having the 
outer and inner perianth whorls 
alike (tot.). 

homochromous (hom'dkro'mus) a. 
[Gk, homos, alike ; chroma, colour.] 
With the whole of the capitular 
florets of one-colour (tot.). 

homodermic (hom'odeYmlk) a. [Gk. 
homos, same ; derma, skin.] Sprung 
from the same embryonic layer 

homodont (hom'6d8nt)#. [Gk. homos, 
same ; odous, tooth.] Having the 
teeth all alike, not differentiated 

homodromous (homod'romus) a. 
[Gk. homos, same ; dromein, to 
run.] Having the genetic spiral 
alike in direction in both stem 
and branches (tot.). 

homodynamy (hom'odin'ami) n. 
[Gk. homos, same ; dynamis, 
power.] Metameric homology 

homoeosis (home'dsis) n. [Gk. homoi- 
osis, likeness.] The assumption by 
one part of the likeness of another 
part, as the modification of an 
antenna into a foot, or of a petal 
into a stamen ; metamorphy (biol.). 

homogamous (homSg'amus) a. [Gk. 
homos, same ; gamos, marriage.] 
Characterizedjay homogamy (biol.). 

homogamy (homog'am!) n. [Gk. 
homos, same ; gamos, marriage.] 
Interbreeding due to some type 
of isolation, e.g. physiological 
isolation (zool.) ; having the flowers 
all alike, having the stamens and 
pistils mature at the same time 

homogangliate (hom'ogang'gllat) a. 
[Gk. homos, same ; ganglion, 
knot.] Having the ganglia of 
the nerve loops symmetrically 
arranged (zool.). 

homogen (hom'qjSn) n. [Gk. homos, 
same ; genos, race.] One of a 
group having a common origin ; 
one of a series of identically 
derived parts (zool.). 

homogeneous (homoje'ngus), homo- 

homogenesis (hom'oje'n'e'sis) n. [Gk. 
homos, same ; genesis, birth.] The 
type of reproduction in which like 
begets like (biol.). 

homogenous (homoj'Snus) a. [Gk. 
homos, same ; genos, race.] More 
or less alike owing to descent 
from a common stock (biol.). 

homogeny (homoj'Snl) n. [Gk. homos, 
same ; genos, race.] Correspond- 
ence between parts due to common 
descent (biol.)^ 

homogony (homfig'onT) n. [Gk. 
homos, same ; gonos, offspring.] 
Condition of having one type of 
flower with equally long stamens 
and pistil (bot.). 

homolomerous (homoifim'e'rus) a. 
[Gk. homoiost like ; meros, part.] 




Having the Algae distributed 
equally through the fungoid 
mycelium, in a lichen (hot.']. 
homoiothermal (homoi'other'mal) a. 
[Gk. homoios, like ; thermos, hot.] 
Warm-blooded (zool.). 
homolecithal (hom'oles'ithal) a. [Gk. 
homos, same ; lekithos, yolk.] Hav- 
ing little deutoplasm, which is 
equally distributed (emb.). 
homologous (homol'bgus) a. [Gk. 
homos, same ; logos, discourse.] 
Resembling in structure and 
origin (biol.). 

homologue (hom'olog) n. [Gk. homos, 
same ; logos, speech.] One of a 
series of structures similar in 
structure and origin (biol.). 
homology (homol'ojT) n. [Gk. homos, 
same ; logos, speech.] The simi- 
larity in structure and development 
of organs or parts (biol.). 
homomallous (hom'omal'us, homom'- 
alus) a. [Gk. homos, same ; mallos, 
lock of wool.] Curving uniformly 
to one side ; appl. leaves (bot.). 
homomorphism (hom'bmor'fizm) n. 
[Gk. homos, same ; morphe, shape.] 
The condition of having perfect 
flowers of only one type (bot.) ; 
hemimetabolism (zool.). 
hoinomorphosis (hom'bmor'fbsis) n. 
[Gk. homos, same ; morphe, shape.] 
The condition of having the newly 
regenerated part like the part re- 
moved (biol.). 

homonculus (homon'kulus) n. [L. 
homunculus, little man.] The 
small miniature of the human 
foetus seen in the spermatozoon, 
according to the Animalculists 

homonomy (homon'omi) n. [Gk. 
homos, same ; nomos, law.] The 
homology existing between parts 
arranged on transverse axes (biol.). 
homonym (hom'bnim) n. [Gk. homos, 
same ; onyma, name.] A name pre- 
occupied, and so unsuitable accord- 
ing to the law of priority (biol.). 
homopetalous(hom'bpe't'alus) a. [Gk. 
homos, same \petalon, petal.] Hav- 
ing all the petals alike (fot.). 
homophyadic (hom'oflad'ik) a. [Gk. 
homos, same ; phyas, shoot.] Pro- 
ducing only one kind of shoot 

homophylic (hom'ofiTlk) a. [Gk. 
homos, same ; phyle, race.] Re- 
sembling one another owing to a 
common ancestry (biol.). 
homophyllous (hom'ofil'us) a. [Gk. 
homos,;phyllon, leaf.] Bear- 
ing leaves which are all of one 
kind (bot.). 

homoplast (hom'oplast) n. [Gk. 
homos, same ; plastos, moulded.] 
An organ formed of similar 
plastids (bot.). 

homoplastic (hom'oplas'tik) a. [Gk. 
homos, same ; plastos, moulded.] 
Pert, homoplasty (biol.). 
homoplasty (hom'bplas'ti) n. [Gk. 
homos, same ; plastos, moulded.] 
Convergence ; resemblance in 
form or structure between differ- 
ent animals or organs due to 
evolution along similar lines 

homoplasy, homoplasty. 
homopterous (homop'terus) a. [Gk. 
homos, same ;pteron, wing.] Having 
the wings alike (zool.). 
homosporous (homos'porus) a. [Gk. 
homos, same ; sporos, seed.] Pro- 
ducing only one kind of spore (bot.). 
homostyled (hom'bstlld) a. [Gk. 
homos, same ; stylos, pillar.] With 
uniform styles (bot.). 
homothermous, homoiothermal. 
homotropous (homot'ropus) a. [Gk. 
homos, same ; trepein, to turn.] 
Erect ; having the micropyle and 
chalaza at opposite ends ; appl. 
ovules (bot.). 

homozygote (hom'ozl'got) n. [Gk. 
homos, same ; zygein, to yoke.] 
An organism in which the char- 
acters are stable, resulting from 
the union of zygotes bearing similar 
characters (biol.). 

homozygous (hom'ozl'gus) a. [Gk. 
homos, same ; zygein, to yoke.] 
Stable (biol.). 

honey-dew, a sugary exudation 
found on the leaves of many plants 
(bot.) ; a sweet secretion produced 
by certain insects, e.g. Aphids 

hooded (hood'gd) a. [A.S. hod.] 
Bearing a hood-like petal ; rolled 
up like a cone of paper, as in 
certain leaves (bot.) ; having the 
head conspicuously and differently 




coloured from the rest of the body ; 
having crests on the head ; having 
wing-shaped expansions on the 
neck, as in the cobra (zool.}. 

hordeaceous (hor'dea'shus) a. [L. 
hordeum, barley.] Pert, or resem- 
bling barley (&?/.). 

horizontal (hor'fzon'tal) a. [Gk. 
horizon, bounding.] Growing in a 
plane at right angles to the primary 
axis (hot.}. 

hormogonium (hor'mogo'nium) n. 
[Gk. hortnos, chain ; goneia, genera 
tion.] That portion of an algal 
filament between two heterocysts 
which, breaking away, acts as a 
reproductive body (boll.}. 

hormones (hormon'z) n. plu. [Gk. 
honnao, to excite.] The secretions 
of ductless glands which pass into 
the blood - vessels by osmosis 

horn (horn) n. [A.S. horn] The 
process on the head of many 
animals ; any projection from an 
animal resembling a horn ; a tuft 
of feathers as in an owl ; a spine 
in fishes ; a tentacle in snails 
(zool.} ; an awn ; any pointed pro- 
jection or process (bot.). 

horn core, the central bony part in 
the hollow-horned ruminants (zool.}. 

host (host) n. [L. hostis, stranger.] 
Any organism in which another 
organism spends a part or the 
whole of its existence, and derives 
some of its nourishment therefrom 

house (hows) n. [A.S. fas.] The 
external gelatinous-like covering 
secreted by certain Tunicates(.sw>/.). 

humeral (hu'me'ral) a. [L. humerus, 
the shoulder.] Pert, shoulder 
region (anat.} ; pert, or naming the 
anterior basal angle of the wing of 
an insect, one of the horny plates 
on the plastron of a turtle (zool.}. 

humerus (hu'me'rus) n. [L. humerus, 
shoulder.] The bone of the upper 
arm (anat., zool.}. 

humistratous (hii'mistra'tiis) a. [L. 
humus, earth ; sternere, to spread.] 
Spreading over the surface of the 
earth (hot.}. 

humour (hu'mor) n. [L. humor, 
moisture.] The fluid of the eye 
(anat.} ; any fluid or juice (phys.}. 

humus (hu'miis) n. [L. humus, earth.] 
A dark soil-like material formed 
by the decomposition of vegetable 
or animal matter (hot.}. 

hunger (hung'ger) n. [A.S. hungor] 
The sensation caused normally by 
the lack of food (phys.}. 

husk (husk) n. [M.E. huske.] The 
outer coating of various seeds (hot.}. 

hyaline (hfalm) a. [Gk. hyalos, 
glass.] Clear ; transparent ; free 
from inclusions (biol.}. 

hyalogen (hl'alqje'n) n. [Gk. hyalos, 
glass ; gignesthai, to produce.] 
Any of the substances found in 
animal tissues which are insoluble 
and related to mucoids (phys.}. 

hyaloid (hfaloid) a. [Gk./tyatos,g\ass.] 
Glassy ; transparent (phys.}. 

hyaloid membrane, a delicate mem- 
brane enveloping the vitreous body 
of the eye (anaf.J. 

hyalomucoid (hl'alomu'koid) n. [Gk. 
hyalos, glass ; L. mucus, mucus ; 
Gk. eidos, like.] One of the non- 
phosphorized gluco-proteids in the 
vitreous humour (phys.}. 

hyaloplasm (hl'aloplazm) n. [Gk. 
hyalos, glass ; plasma, something 
moulded.] The ground substance 
of the cell as distinguished from 
the microsomes, or as distinguished 
from the reticulum or spongioplasm 
(zool.} the ectoplasm or peripheral 
zone in plant cells (bot.}. 

hyaloplasma, hyaloplasm. 

hyalopterous (hfalop'tgrus) a. [Gk. 
hyalos, glass ; pteron, wing.] Having 
transparent wings (zool.}. 

hyalosome (hi'alosom') n. [Gk. hyalos, 
glass ; soma, body.] A nucleolar- 
like body in a cell-nucleus, only 
slightly stainable by nuclear or 
plasma stains (biol.}. 

hybrid (hl'brid) n. [L. hibrida, 
a cross.] Any cross-bred animal 
or plant (biol.}. 

hybridism (hl'bridizm) n. [L. hibrida, 
a cross.] The state or quality of 
being a hybrid (biol.}. 

hybridization (hl'brldiza'shun) n. [L. 
hibrida, a cross.] Act or process 
of hybridizing ; state of being 
hybridized (biol.}. 

hybridize (hl'brldlz) v. [L. hibrida, 
a cross.] To interbreed, to produce 
hybrids (biol.}. 




hydathode (hl'dathod) n. [Gk. hydor, 
water ; odos, way.] An epidermal 
structure specialized for the secre- 
tion of water (bof.). 

hydatid (hl'datid) n. [Gk. hydatis, 
watery vesicle.] Any vesicle or 
sac filled with a clear watery-like 
fluid, and containing encysted 
stages of the larval tapeworms 

hydatiform (hldat'ff6rm) a. [Gk. 
hydatis, watery vesicle ; L. forma, 
shape.] Resembling a hydatid 

hydatigenous (hi'datlj'gnus) a. [Gk. 
hydatis, watery vesicle ; gignesthai, 
to produce.] Producing or forming 
hydatids (zool.). 

hydranth (hl'dranth) n. [Gk. hydor, 
water ; anthos, flower.] A nutri- 
tive zooid in a hydroid colony 

hydrocaulis (hi'drok61'is) n. [Gk. 
hydor, water ; kaulos, stalk.] The 
branching vertical portion of the 
coenosarc in a hydroid colony 

hydrocircus (hl'droseVkus) n. [Gk. 
hydor, water ; kirkos, circle.] The 
hydrocoelic ring surrounding the 
mouth in Echinoderms (zool.). 

hydrocladia (hl'droklad'ia) n. plu. 
[Gk. hydor, water ; klados, short.] 
The secondary branches of a 
hydrocaulis (zool.). 

hydrocoel (hi'drosel) n. [Gk. hydor, 
water ; koilos, hollow.] The water- 
vascular system in the Echino- 
derms (zool.). 

hydrocyst (hfdrosist) n. [Gk. hydor, 
water ; kystis, bladder.] A dactylo- 
zooid (zool). 

hydroecium (hldre'shium) n. [Gk. 
hydor, water ; oikos, house.] A 
closed tube at the upper end of a 
Siphonophore ; an infundibulum 

hydroid (hl'droid) n., a. [Gk. hydor, 
water ; eidos, resemblance.] A 
tracheid (tot.) ; pert, or similar to 
the genus hydra ; the polyp form 
of a Hydrozoan (zool.). 

hydrolysis (hldrol'isis) n. [Gk. hydor, 
water ; lyein, to dissolve.] De- 
composition of a chemical com- 
pound by the addition of water 

hydrome (hi'drom) n. [Gk. hydor, 
water ; mestos, full.] Any tissue 
that conducts water (6ot.). 

hydromegatherm (hl'dromSg'a.thgrm) 
n. [Gk. hydor, water ; mega, 
great ; therme, heat.] A plant 
which must have both moisture 
and heat to develop fully (dot.}. 

hydrophilous (hldrof'ilus) a. [Gk. 
hydor, water ; philein, to love.] 
Pollinated through the agency of 
water (dot.). 

hydrophyllium (hl'drofil'ium) n. [Gk. 
hydor, water ; phyllon, leaf.] One 
of leaf-like transparent bodies 
arising above and partly covering 
the sporosacs in a Siphonophore 

hydrophyte (hfdroflt) n. [Gk. hydor, 
water ; phyton, plant.] An aquatic 

hydrophyton (hidrof'iton) n. [Gk. 
hydor, water ; phyton, plant.] A 
complete hydroid colony, root- 
like organ, stem and branches 

v (zool.). 

hydroplanula (hi'droplan'ula) n. [Gk. 
hydor, water ; L. planus, flat. J A 
stage in the larval history of a 
Coelenterate between a planula and 
an actinula (zool.). 

hydropolyp (hl'dropol'ip) n. [Gk. 
hydor, water ; F. polype, polyp.] 
A polyp of a hydroid colony ; a 
hydrula (zool.). 

hydropore (hl'dropor) n. [Gk. hydor, 
water \poros, opening.] The open- 
ing into the right hydrocoel in the 
echinoderm larvae (zool.). 

hydrorhiza (hl'drorl'za) n. [Gk. hydor, 
water ; rhiza, root.] The creeping 
root-like portion of the coenosarc 
of a hydroid colony (zool.). 

hydrosome (hl'drosom) n. [Gk. hydor, 
water ; soma, body.] The con- 
spicuously hydra-like stage in a 
coelenterate life-history (zool.). 

hydrospire (hl'drdspir) n. [Gk. hydor, 
water ; L. spira, coil.] The folds 
on the stereom of blastoids ; re- 
spiratory structures (pal.). 

hydrostome (hl'drostom) n. [Gk. 
hydor, water ; stoma, mouth.] The 
mouth of a hydroid polyp (zool.). 

hydrotaxis (hi'drotak'sis) n. [Gk. 
hydor, water ; taxis, arrangement.] 
The response of certain small 




organisms or of certain organs to 
the stimulus of water (biol.}. 
hydrotheca (hl'drothe'ka) n. [Gk. 

hymen, skin ; pherein, to carry.] 
The hymen portion of the sporo- 
phore of a fungus (bot.}. 

hydor, water ; theke, cup.] The hymenopterous (hl'me'nop'tSrus) a. 

cup-like structure into which the 

polyp may withdraw, found in 

many Coelenterates ; a product of 

the ectoderm (zool.}. 
hydrotropism (hldrot'ropTzm) n. [Gk. 

hydor, water ; trepein, to turn.] 

hydrula (hl'droola) n. [Gk. hydor, 

water.] A hypothetical simple 

polyp (zool.}. 
hygrophilous (higrof'Ilus) a. [Gk. 

hygros, wet ; philein, to love.] In- 
habiting moist or marshy places 

hygrophyte (hl'grofit) n. [Gk. hygros, 

wet ; phyton, plant.] A plant which 

lives and thrives under conditions 

of plentiful moisture (bot.}. 
hygroplasm (hl'groplazm) n. [Gk. 

hygros, wet ; plasma, something 

moulded.] The more liquid part. 

of protoplasm ; cf. stereoplasm. 

hygroscopic (hi'groskop'ik) a. [Gk. -^ 

hygros, wet ; skopein, to regard..3t/hyomandibular (hf omandib'ul&r) a. 

Sensitive to moisture (bot.}. . *\ 

[Gk. hymen, skin ; pteron, wing.] 
Having membranous wings ; appl. 
certain insects (zool.}. 

hyobranchial (hl'obrang'kfal) a. [Gk. 
T ; brangchia, gills.] Pert, gills 
and hyoid (zool.}. 

hyoepiglottic (hfoepiglot'ik) a. [Gk. 
T ; epi, upon ; glotta, tongue.] 
Connecting the hyoid and the epi- 
glottis (anat.}. 

hyoglossal (h6glos'al) a. [Gk. T; 
glossa, tongue.] Pert, tongue and 
hyoid (anat.}. 

hyoid (hi'oid) a. [Gk. hyoeides, Y- 
shaped.] Pert, or designating a 
bone or series of bones lying at 
the^base o\the tongue and de- 
veioped 4^p m tne hyoid arch of 
ine embryo (anat.}. 

hyoideus (hloid'cus) n. [Gk. hvocides, 
Y-shped.] A nerve which sup- 
pji^s the mucosa of the mouth and 

Ofche muscles of the hyoid region 

hylophagous (hllof'Xgus) a. 

hyle, wood ; phagein, to eat.] Eat- 
ing wood ; appl. certain insects 

hylophyte (hl'loflt) n. [Gk. hyle, 
wood ; phyton, plant.] A plant 
growing in woods (bot.}. 

hylotomous (hllot'omus) a. [Gk. hyle, 
wood ; temnein, to cut.] Wood- 
cutting ; appl. certain insects 

hymen (hi'm&n) n. [Gk. hymen, mem- 
brane.] A thin fold of mucous 
membrane situated at the orifice 
of the vagina (anat.}. 

[Gk. T ; L. mandibulum, jaw.] Pert. 
hyoid and the mandible ; pert. 
dorsal segment of the hyoid arch 
in fishes ; n., the dorsal segment 
itself of the hyoid arch in fishes 

hyomental (hi'timgn'tal) a. [Gk. X ; 
L. mentum, chin.] Pert, hyoid and 
chin (anat.}. 

hyoplastron (hfoplas'tron) n. [Gk. 
X ; F. plastron, breast-plate.] The 
second lateral plate in the plastron 
of Chelonians (zool.}. 

hyosternum (hfosteYnum) n. [Gk. 
T; sternon, breast.] The hyo- 
plastron (zool.}. 

hymenial (hlme'nlal) a. [Gk. hymen, hyostylic (hfostil'ik) a. [Gk. X ; 

skin.] Pert, hymenium (bot.}. 

hymeniferous (hi'm6nTf'6rus) a. [Gk. 
hymen, skin ; L. ferre, to carry.] 
Having a hymenium (bot.}. 

hymenium (hl'me'nium) n. [Gk. 
hymen, skin.] The outermost layer 
of a mushroom lamellae, or similar 
fungus, consisting of barren cells 
or paraphyses and basidial cells 

hymenophore (hfmSnofor) n. [Gk. 

stylos, pillar.] Having the jaw 
articulated to the skull by the 
agency of the hyomandibular or 
corresponding part (zool.}. 

hyothyroid (hfothfroid) a. [Gk. T ; 
thyreos, shield ; eidos, like.] Pert. 
the hyoid and the thyroid cartilages 
of the larynx ; appl. structures 
associated with them (zool.}. 

hypallelomorph (hi'pal61 / 6m6rf) n. 
[Gk. hypo, under ; allelon, of one 




another ; morphe, shape.] Allelo- 
morphs which under certain con- 
ditions are themselves compound 

hypanthium (hipan'thmm) n. [Gk. 
hypo, under ; anthos, flower.] Any 
enlargement of the torus (dot.}. 

hypanthodium (hip'antho'dium) n. 
[Gk. hypo, under ; anthodes, like 
flowers.] An inflorescence with a 
concave capitulum on the walls of 
which the flowers are arranged 

hypantrum (hipan'trum) n. [Gk. 
hypo, under ; antron, cave.] A 
notch on the vertebrae of certain 
reptiles for articulation with the 
hyposphene (pal.}. 

hypapophysis (hip'apof'isis) n. [Gk. 
hypo, under ; apo, upon ; phyein, to 
grow.] A ventral process on a 
vertebra (anat.}. 

hyparterial (hip'arte'rial) a. [Gk. 
hypo, under ; L. arteria, channel.] 
Situated below an artery ; appl. 
branch of the right bronchus 

hypaxial (hipak'sial) a. [Gk. hypo, 
under ; L. axis, axis.] Ventral, or 
below the vertebral column ; appl. 
muscles (zool.}. 

hyperapophysis (hi'perapof'isis) n. 
[Gk. hyper, above ; apo, from ; 
phyein, to grow.] A postero-lateral 
process of the dorsal side of a 
vertebra (zool.}. 

hyperchromasy (hl'perkro'masT) n. 
[Gk. hyper, above ; chroma, colour.] 
A relatively superabundant supply 
of chromatin to cytoplasm in a cell 

hyperchromatosis (hi'perkro'mato'sis) 
n. [Gk. hyper, above ; chroma, 
colour.] The excess of nuclear 
substance in a cell just previous to 
division (zool.}. 

hypercoracoid (hl'pfirkor'akoid) a. 
[Gk. hy^per, above ; korax, crow ; 
eidos, like.] Pert, or designating 
the upper bone at the base of a 
pectoral fin in Fishes (zool.}. 

hypermetamorphosis (hl'perme't'a- 
mor'fosis) n. [Gk. hyper, above ; 
meta, after ; morphe, shape.] A 
protracted and thoroughgoing 
metamorphosis (zool.}. 

hyperparasite (hl'perpar'aslt) n. [Gk. 

hyper, above ; para, beside ; sites, 
food.] A parasite which is para- 
sitic on or in another parasite 

hyperpnoea (hl'perpne'a) n. [Gk. 
hyper, above ; pnoe, breath.] Rapid 
breathing due to an insufficient 
supply of oxygen (phys.}. 

hyper-sensitivity (hl'pgrsen'sitiv'itT) n. 
[Gk. hyper, above ; L. sentire, to 
feel.] A condition of being unduly 
sensitive to any drug (phys.}. 

hypertely (hlper't&li) n. [Gk. hyper, 
above ; telos, end.] Any imitation 
in colour or pattern which has 
overshot the mark (zool.}. 

hypertonia (hi'pgrto'ma) n. [Gk. 
hyper, above ; tonos, tone.] Ex- 
cessive tonicity (phys.}. 

hypertrophy (hlper'troff) n. [Gk. 
hyper, above ; trophe, nourishment.] 
An excessive growth or develop- 
ment (biol.}. 

hypha (hi'fa) n. [Gk. hyphe, web.] 
The thread-like element of the 
vegetative mycelium of a Fungus 

hyphasma (hifaz'ma) n. [Gk. hyphas- 
ma, thing woven.] A barren 
mycelium (bot.}. 

hyphodrome (hl'fodrom) n. [Gk. 
hyphe, web ; dromein, to run.] 
Running throughout the tissues ; 
appl. thick leaves where the veins 
are not visible from the surface 

hypnocyst (hlp'nosist) n. [Gk. hypnos, 
sleep ; kystis, bladder.] A cyst in 
which the contained organism 
simply rests (zool.}. 

hypnody (hlp'nodl) n. [Gk. hypnodia, 
sleepiness.] The long resting 
period passed by certain larval 
forms (zool.}. 

hypnogenic (hip'nojen'ik) a. [Gk. 
hypnos, sleep ; genos, offspring.] 
Sleep-producing ; appl. influences 
or localities which tend to produce 
hypnosis (phys.}. 

hypnospenn (hip'nosperm) n. [Gk. 
hypnos, sleep ; spernia, seed.] A 
hypnospore (bot.}. 

n. [Gk. hypnos, sleep ; sporos, 
seed ; anggeion, vessel.] A spor- 
angium containing resting spores 




hypnospore (hip'nospor) //. [Gk. 
hypnos, sleep ; sporos, seed.] A 
resting spore ; a zygote that re- 
mains in a quiescent condition 
during winter (dot.}. 

hypoarion (hl'poar'ion) n. [Gk. hypo, 
under ; oarion, little egg.] A small 
lobe below the optic lobes of most 
Teleosts (zool.). 

hypobasal (hl'poba'sal) n. [Gk. hypo, 
under ; L. basis, base.] The lower 
segment of a developing ovule 

hypoblast (hl'poblast) n. [Gk. hypo, 
under ; blastos, bud.] The inner 
germ layer in a gastrula (emb.), 

hypoblastic (hl'poblas'tlk) a. [Gk. 
hypo, under ; blastos, bud.] Pert. 
or derived from the inner layer ; 
endodermal (biol.). 

hypobranchial (hl'pobrang'kial) a. 
[Gk. hypo, under ; brangchia, gills.] 
Pert, the lower or fourth segment 
of the branchial arch (anat.). 

hypocentrum (hfpose'n'trum) n. [Gk. 
hypo, under ; kentron, centre.] A 
transverse cartilage that arises 
below the nerve cord and forms 
part of the vertebral centrum 

hypochilium (hl'pokil'ium) . [Gk. 
hypo, under ; cheilos, lip.] The 
lower portion of the lip of an orchid 

hypochondrium (hl'pokon'drlum) ;/. 
[Gk. hypo, under ; chondros, carti- 
lage.] A region below the epigastric 
and above the lumbar (anat.). 

hypochordal (hl'pokor'dal) a. [Gk. 
hypo, under ; chorde, string.] Below 
the notochord (anat). 

hypocleidium (hi'pokli'dium) n. [Gk. 
hypo, under ; kleis, key.] The 

hypocone (hi'pokon) n. [Gk. hypo, 
under ; konos, cone.] The postero- 
internal cusp of an upper molar 

hypoconid (hi'poko'nid) n. [Gk. hypo, 
under ; konos, cone.] The postero- 
buccal cusp of a lower molar 

hypoconulid (hl'pokon'ulid) n. [Gk. 
hypo, under ; konos, cone.] The 
postero-mesial cusp of a lower 
molar (zool.). 

hypocoracoid (hfpokor'akoid) a. [Gk. 

under ; korax, crow ; eiiios, 
like.] Pert, the lower bone at the 
base of the pectoral fin in Fishes 

hypocotyl (hi'pokot'il) n. [Gk. hypo, 
under ; kotyle, hollow.] That por- 
tion of the stem below the coty- 
ledons in an embryo (emb.). 

a. [Gk. hypo, under ; kotyle, hol- 
low.] Below the cotyledons 

hypocrateriform (hi'pokrater'iform) a. 
[Gk. hypo, under ; krater, cup ; L. 
forma, shape.] Having a gamo- 
petalous corolla with a long narrow 
tube, and the limbs at right angles 
- to the tube (bot.). 

hypodactylum (hl'podak'tilum) n. 
[Gk. hypo, under ; daktylos, digit.] 
The under surface of a bird's toes 

hypodenna (hi'podeYma) n. [Gk. 
hypo, under ; derma, skin.] The 
tissue just under the epidermis in 

hypodermal (hl'poder'mal) a. [Gk. 
hypo, under ; derma, skin.] Pert. 
the hypoderma or hypodermis 

hypodermalia (hl'poderma'lTa) n. 
[Gk. hypo, under ; derma, skin.] 
Sponge spicules situated just below 
the derma or skin (zool.). 

hypodermic (hi'podeYmik) a. [Gk. 
hypo, under ; L. dennis, skin.] 
Pert, the parts just under the skin 

hypodermis (hl'podgr'mis) n. [Gk. 
hypo, under ; L. dermis, skin.] The 
cellular layer lying beneath and 
secreting the cuticle of the Annu- 
lata, Arthropoda, etc. ; the hypo- 
blast (zool.) ; hypodema (bot.). 

hypodicrotic (rifpodikrot'ik) a. [Gk. 
hypo, under ; di, two ; krotein, to 
beat.] Exhibiting the phenomenon 
of having two arterial beats for the 
one cardiac (phys.). 

hypogastric (hl'pogas'trlk) a. [Gk. 
hypo, under ; gaster, belly.] Pert. 
the lower median region of the 
abdomen (anat.). 

hypogastrium (hi'pogas'trium) . 
[Gk. hypo, under ; gaster, belly.] 
The lower median region of the 
abdomen (anat.). 




hypogeal (hl'pqje'al) a. [Gk. hypo, 
under ;gaia, earth.] Subterranean ; 
appl. stems, etc. (dot.). 

hypogenesis (hfpojgn'gsis) n. [Gk. 
hypo, under ; genesis, origin.] De- 
velopment without alternation of 
generations occurring (bzol.). 

hypogenous (hlpoj'e'nus) a. [Gk. 
hypo, under ; genos, birth.] Grow- 
ing on the lower surface of anything 

hypogeous (hi'poje'us) a. [Gk. hypo, 
under ; ge, earth.] Growing or 
maturing under the earth (hot., 

hypoglossal (hl'poglos'al) n. [Gk. 
hypo, under ; glossa, tongue.] The 
twelfth paired cranial nerve, dis- 
tributed to the base of the tongue 

hypoglottis (hl'poglot'is) n. [Gk. 
hypo, under ; glotta, tongue.] The 
under part of the tongue (anat.) ; 
a division of the labium of beetles 

hypognathous (hl'pogna'thus, hipog'- 
nathus) a. [Gk. hypo, under ; 
gnathos, jaw.] Having the lower 
jaw slightly longer than the upper 

hypogynium (hi'pqjin'ium) n. [Gk. 
hypo, under ; gyne, female.] That 
structure which supports the ovary 
in such plants as sedges (bot.). 

hypogynous (hipqj'inus) a. [Gk. 
hypo, under ; gyne, female.] In- 
serted below the gynoecium, and 
not adherent ; cf. perigynous 

hypohyal (hl'pohl'al) n. [Gk. hypo, 
under ; hyoeides, Y-shaped.] The 
hyoid element lying between the 
ceratohyal and the basihyal (anat.). 

hypoischium (hl'pois'kTum) n. [Gk. 
hypo, under ; ischion, hip.] A small 
bony rod passing backwards from 
the ischiadic symphysis and sup- 
porting the ventral cloacal wall 

hypomere (hl'pomer) n. [Gk. hypo, 
under ; meros, part.] The lower 
or lateral plate zone of the coelomic 
pouches (emb.\ 

hypomeron (hlporn'e'ron) n. [Gk. 
hypo, under ; meros, part.] The 
lateral inflexed side of a coleopter- 
ous prothorax (zool.). 

hyponasty (hl'ponas'ti) n. [Gk. hypo, 
under ; nastos, close-pressed.] The 
state of growth in a flattened 
structure in which the under surface 
grows more vigorously than the 
upper (bot.). 

hyponome (hl'ponom) n. [Gk. hypo- 
nome, underground passage.] The 
funnel of the Cephalopods (zool., 

hyponychium (hi'ponik'ium) n. [Gk. 
hypo, under ; onyx, nail.] The 
layer of epidermis on which the 
nail rests (anat.}. 

hypopetalous (hl'popet'alus) a. [Gk. 
hypo, under ; petalon, petal.] Hav- 
ing the corolla inserted below and 
not adherent to the gynoecium 

hypophare (hi'pofar) n. [Gk. hypo, 
under ; pherein, to bear.] The 
lower part of the sponge in which 
there are no chambers ; cf. spongo- 
phare (zool.). 

hypopharyngeal (hi'pofarin'jeal, -far'- 
inje'al) a. [Gk. hypo, under ; 
pharynx, pharynx.] Pert, or situ- 
ated below or in the lower surface 
of the pharynx (zool.). 

hypopharynx (hl'pofar'ingks) n. [Gk. 
hypo, under ; pharynx, pharynx.] 
The lingua of many insects ; in 
mosquitoes, an outgrowth from the 
base of the labium which bears the 
salivary groove or duct (zool.). 

hypophloeodal (hi'pofle'odal) a. [Gk. 
hypo, under ; phloios, bark.] Liv- 
ing or growing under the bark 

hypophyllium (hi'poffl'ium) n. [Gk. 
hypo, under ; phyllon, leaf.] A 
scale-like leaf below a cladophyll 

hypophysial (hl'pofiz'ial) a. [Gk. 
hypo, under ; physis, growth.] 
Pert, the hypophysis (anat.). 

hypophysis (hlpof'isis) n. [Gk. hypo, 
under ; physis, growth.] The pitu- 
itary body (anat.) ; the olfactory 
pit in the lancelet (zool.) ; the last 
cell of the suspensor (bot.). 

hypoplastron (hl'poplas'tron) n. [Gk. 
hypo, under ; F. plastron, shield.] 
The third lateral bony plate in the 
plastron of turtles (zool,). 

hypopodium (hfpopo'dium) . [Gk. 
hypo, under ; podion, little foot.] 




The basal portion of any leaf, in- 
cluding the stalk (dot.). 

hypoptilum (hlpop'tllum) n. [Gk. 
hypo, under ; ptilon, down.] The 
after-shaft (zool.}. 

hypopygium (hl'pdplg'mm, hfpopi'- 
jmm) n. [Gk. hypo, under ; pyge, 
buttocks.] The clasping organ of 
a male dipterous insect (zool.}. 

hyporachis (hi'pora'kis) . [Gk. hypo, 
under ; rhachis, spine.] The stem 
of the after-shaft of a feather 

hyporhachis, see hyporachis. 

hyposkeletal (hrposkel'Stal) a. [Gk. 
hypo, under ; skeletos, hard.] Lying 
beneath or internally to the endo- 
skeleton (zool.}. 

hyposphene (hi'posfen) n. [Gk. hypo, 
under ; sphen, wedge.] A wedge- 
shaped process on the neural arch 
of the vertebrae of certain extinct 
reptiles which fits into the hypan- 
trum (pal.}. 

hypostereom (hl'posteYeom) . [Gk. 
hypo, under ; stereos, solid.] The 
third or inner layer of the thecal 
plates of a Cyst id ; the inner layer 
of the integument of a Crinoid 

hypostoma (hi'posto'ma) n. [Gk. 
hypo, under ; sfoma, mouth.] The 
fold bounding the posterior margin 
of the oral aperture in Crustacea ; 
the oral projection or manubrium 
of a Hydrozoan (zool.}. 

hypostomatous (hfpostom'atus) a. 
[Gk. hypo, under ; stoma, mouth.] 
Having the mouth placed on the 
lower or ventral side (zool.}. 

hypostome, see hypostoma. 

hypotarsus (hl'potar'sus) n. [Gk. 
hypo, under ; tarsus, ankle.] The 
" calcaneum " of a bird (zool.}. 

hypothalamus(hl'potharamus). [Gk. 
hypo, under; thalamos, chamber.] 
The subthalamic tegmental region 
and the structures forming the 
greater part of the floor of the 
third ventricle (anat.}. 

hypothallus (hl'pothal'us) n. [Gk. 
hypo, under ; thallus, flattened 
plate.] The marginal hyphal out- 
growth ; a membranous case bear- 
ing sporangia (bot.}. 

hypothecium (hl'pothe'sTum, -shlum) 
. [Gk. hypo, under ; theke, cup.] 

The layer of dense hyphal threads 
below the thecium in Lichens ; the 
upper layer of the ascoma (bot.}. 

hypothenar (hi'pothe'nar) a. [Gk. 
hypo, under ; thenar, palm of the 
hand.] Pert, the prominent part 
of the palm of the hand above the 
base of the little finger (anat.}. 

hypothetical units, the ultimate 
component parts of protoplasm ; 
ultracellular units ranking between 
the molecule and the cell ; also 
called variously, physiological units, 
pangens, gemmules, biophores, 
bioblasts, somacules, idiosomes, pla- 
somes, micellae, plastidules, inotag- 
mata, idioblasts, biogens, gemmae, 
and microzymas (biol.}. 

hypotonic (hfpotSn'ik) a. [Gk. hypo, 
under ; tonos, tension.] Appl. a 
solution whose osmotic pressure is 
less than that of serum (phys.}. 

hypotrichous (hlpot'rlkus) a. [Gk. 
hypo, under ; thrtx, hair.] Pert. 
Infusorians in which the cilia are 
mainly restricted to the under sur- 
face, and often form strong seta- 
like structures (zool.}. 

hypotrochanteric (hl'potrok'anteVik) 
a. [Gk. hypo, under ; trochanter, 
runner.] Beneath the trochanter 

hypotympanic (hr'potlm'panik) a. 
[Gk. hypo, under ; L. tympanum, 
drum.] Situated below the tym- 
panum ; pert, the quadrate (anat.}. 

hypoxanthin (hfpozan'thln) n. [Gk. 
hypo, under ; xanthos, yellow. J A 
crystalline nitrogenous substance 
found in muscle tissue and in some 
seeds (phys.}. 

hypozygal (hfpozl'gal) n. [Gk. hypo, 
under ; zygon, yoke.] The lower 
ossicle of a syzygial pair bearing no 
pinnule (zool.}. 

hypselodont (hlp'selodont) a. [Gk. 
hypsi, high ; odous, tooth.] Hypso- 

hypsodont (hlp'sodont) a. [Gk. 
hypsos, height ; odous, tooth.] Pert. 
or designating teeth with high 
crowns and short roots (zool.}. 

hypsophyll (hip'sofll) n. [Gk. hypsi, 
high ; phyllon, leaf.] Any leaf 
beneath the sporophylls (bot.}. 

hypural (hlp'ural) a. [Gk. hypo, 
under ; oura, tail.] Pert, a bony 




structure, formed by the fused 
haemal spines of the last few 
vertebrae, which supports the caudal 
fin in certain Fishes (zool). 
hysterogenic (his'terojen'ik) a. [Gk. 
hysteros, later ; genos, birth.] Of 
later development or growth (zool.}. 


ichthyic (ik'thnk) a. [Gk. ichthys, 
fish.] Pert, or characteristic of 
Fishes (zool.). 

ichthyoid (ik'thioid) a., ichthyic. 

ichthy elite (ik'thidllt) n. [Gk. ichthys, 
fish ; lithos, stone.] A fossil fish or 
part of one (pal.). 

ichthyology (ikthiol'oji) n. [Gk. 
ichthys, fish ; logos, discourse.] 
That part of zoology treating of 

ichthyopterygia (ik'thiopterij'ia) n. 
plu. [Gk. ichthys, fish ; pteryx, 
wing or fin.] Paired fish fins 

icosandrous (I'kosan'drus) a. [Gk. 
eikosi, twenty ; aner, man.] Having 
twenty or more stamens (pot.). 

id (id) n. [Gk. idios, distinct.] A 
hypothetical structural unit ; the 
chromomere (cyt.). 

idant (1'dant) n. [Gk. idios, distinct.] 
A unit resulting from an aggrega- 
tion of ids ; the chromosome (cyt.). 

idioblast (id'ioblast) n. [Gk. idios, 
distinct ; blastos, bud.] A bio- 
phore ; an ultimate cell unit. See 
hypothetical units. 

idiochromatin (id'iokro'matin) n. [Gk. 
idios, distinct ; chroma, colour.] 
Temporarily dormant generative 
chromatin ; cf. trophochromatin 

idiochromidia (id'iokromld'ia) n. plu. 
[Gk. idios, distinct ; chroma, colour.] 
Sporetia ; generative chromidia ; 
cf. trophochromidia (cyt.). 

idiochromosome (id'iokro'mosom) n, 
[Gk. idios, distinct ; chroma, colour ; 
soma, body.] An additional chromo- 
some with a relation to sex, ob- 
served in certain germ cells one or 
more may be present (cyt.). 

idiomuscular (id'fomus'kular) a. [Gk. 

idios, personal ; L. musculus, 
muscle.] Appl. contraction of a 
degenerated muscle artificially 
stimulated (phys.). 

idioplasm (id'ioplazm) n. [Gk. 
idios, distinct ; plasma, something 
moulded.] Chromatin ; the genera- 
tive or germinal part of a cell ; cf. 
trophoplasm (cyt.). 

icliosome (id'iosom) n. [Gk. idios, 
distinct ; soma, body.] An idio- 
blast or biophore. See hypotheti- 
cal units. 

idiothalamous (id'iothal'amus) a. 
[Gk. idios, personal ; thalamos, 
receptacle.] Appl. Lichens in 
which various parts are differently 
coloured from the thallus (bot.). 

idiothermous (id'iother'mus) a. [Gk. 
idios, personal ; thermos, hot.] 
Warm - blooded ; homoiothermal 

idiozome (id'ib'zom) n. [Gk. idios, 
distinct ; zoma, girdle.] In sper- 
matogenesis a separated portion of 
archoplasm which ultimately be- 
comes the head-cap of the sperma- 
tozoon (cyt.). 

idorgan (idor'gan) n. [Gk. idios, 
distinct ; organon, instrument.] A 
purely morphological multicellular 
unit which does not possess the 
features of a soma (biol.). 

ileocaecal (H'eose'kal) a. [L. ileum, 
groin ; caecus, blind.] Pert, ileum 
and caecum ; appl. fossae, folds, 
etc. (anat.). 

ileocolic (il'eokol'fk) a. [L. ileum, 
groin ; kolon, the gut.] Pert, ileum 
and colon ; appl. artery, lymph 
gland, etc. (anat.). 

ileum (il'eum) n. [L. ileum, groin.] 
The lower part of the small in- 
testine (anat.). 

iliac (Il'lak) a. [L. ilia, flanks.] Pert. 
ilium, a pelvic bone ; appl. artery, 
fossa, furrow, tuberosity, vein, 
muscle, etc. (anat.). 

iliocaudal (Il'ioko'dal) a. [L. ilia, 
flanks ; cauda, tail.] Connecting 
ilium and tail ; appl. muscle (anat.). 

iliococcygeal (iliokok'sije'al, -koksij'- 
eal) a. [L. ilia, flanks ; Gk. kokkyx, 
cuckoo.] Pert, ilium and coccyx ; 
appl. a muscle (anat.). 

iliocostal (Tl'fokos'tal) a. [L. ilia, 
flanks ; costa, rib.] In region of 




ilia and ribs ; appl. several muscles 

iliofemoral (Tl'iofgm'oral) a. [L. ilia, 
flanks ; femur, thigh.] Pert, the 
ilium and femur ; appl. a ligament 

iliohypogastric (Tl'iohl'pogas'trik) a. 
[L. ilia, flanks ; Gk. hypo, under ; 
gaster, belly.] Pert, ilium and 
lower anterior part of the abdomen ; 
appl. a nerve (anaf.). 

ilioinguinal (il'ibin'gwlnal) a. [L. 
ilia, flanks ; in%uen, the groin.] In 
the region of ilium and groins ; 
appl. a nerve (anaf.). 

illolumbar (il'Iolum'bar) a. [L. ilia, 
flanks ; lumbus, loins.] In region 
of ilium and loins ; appl. artery, 
ligament, vein (anaf.). 

iliopectineal (Tl'fope'ktin'eal) a. [L. 
ilia, flanks ; pecten, crest.] Appl. 
an eminence marking the point of 
union of ilium and pubis (anaf.). 

iliotibial (il'iotib'ial) a. [L. ilia, 
flanks ; tibia, pipe.] Appl. a tract 
or band of muscle at the lower end 
of the thigh (anaf.). 

iliotrochanteric (il'iotrokanter'ik) a. 
[L. ilia, flanks ; Gk. trochanter, a 
runner.] Uniting ilium and tro- 
chanter of femur ; appl. a ligament 

ilium (Ilium) n. [L. ilium, flank.] 
That part of the hip-bone supporting 
the flank (anaf.) ; the dorsal bone, 
articulating with the backbone, of 
the pelvic arch (zoo/.). 

imaginal (imaj'inal) a. [L. imago, 
image.] Pert, an imago ; appl. 
larval discs, patches of cells from 
which new organs develop (zool.). 

imago (Ima'go) n. [L. imago, image.] 
The last or adult stage in insect 
metamorphosis ; the perfect insect 

imbricate (im'brikat) a. [L. imbricare, 
to tile.] Having parts overlying 
each other like house-tiles ; appl. 
scales, plates, etc. (zool.} ; bud- 
scales, bracts, etc. (hot}. 

imitative (im'itativ) a. [L. imitari, 
to imitate.] Appl. form, structure, 
habit, colouring, etc., assumed for 
protection (zool}. 

immaculate (fmak'ulat) a. [L. in, 
not ; macula, spot.] Without spots 
or marks of different colour. 

immunise (Tm'unlz, imu'nlz) v. [L. 
immunis, free.] To render invul- 
nerable to a toxin, usually by 
injecting the toxin in small quanti- 
ties at short intervals, without the 
appearance of severe symptoms 

immunity (imu'nTt!) n. [L. immunis, 
free from duty.] An organism's 
resistance, natural or acquired, to 
the onset of pathological conditions 
from infection, natural or artificial, 
by any of the micro-organisms 

imparidigitate (impar'idij'itat) a. [L. 
impar, unequal ; digitus, finger.] 
Having an odd number of digits 
on a limb (zool}. 

imparipinnate (impar'ipin'at) a. [L. 
impar, unequal ; pinna, wing.] Un- 
equally pinnate ; pinnate with an 
odd terminal leaflet (hot}. 

imperfect metamorphosis, see in- 

imperforate (ImpeVforat) a. [L. in, 
not ; per, through ; foratus, bored.] 
Not pierced ; appl. foraminifera 
shells without fine pores in addition 
to principal opening (zool.}. 

impervious (TmpeVvIus) a. [L. in, 
not ; per, through ; via, way.] Not 
permeable (biol} ; appl. nostrils 
with a septum between the nasal 
cavities (zool}. 

import (im'port) n. [L. importare, to 
bring in.] A method of food- 
ingestion in Amoeba, food being 
drawn in on contact (phys}. 

impregnation (im'prggna'shun) n. [L. 
impraegnare, to fertilize.] Trans- 
ference of spermatozoa from male 
to body of female. 

impression (impre'sh'on) n. [L. in, 
into ; premere, to press.] An in- 
dentation mark resulting from con- 
tact of organs or pressure of one 
on another, as those on the surfaces 
of the liver, the rhomboid of the 
clavicle, the trigeminal of the 
temporal (anaf.). 

inantherate (Inan'thgrat) a. [L. in, 
not ; Gk. antheros, flowery.] With- 
out anthers (bot}. 

inarticulate (Tnartik'ulat) a. [L. in, 
not ; articulatus, jointed.] Not 
segmented (biol}. 

inaxon (inak'son) n. [Gk. is, fibre ; 




axon, axis.] A nerve-cell with axis- 
cylinder branching at a distance 
from it (phys.). 

inbreeding, breeding through a suc- 
cession of parents belonging to the 
same stock, or very nearly related 

incaliculate (Tnkalik'ulat) a. [L. in, 
not ; caliculus, small flower-cup.] 
Wanting a calicle (zoo!.). 

incasement theory, see preforma- 
tion theory. 

incised (TnsTzd') a. [L. incisus, cut 
into.] With deeply notched margin 

incisiform (insl'zif6rm) a. [L. incisus, 
cut into ; forma, shape. J Incisor- 

incisive (insl'zlv) a. [L. incisus, cut 
into.] Pert, or in the region of the 
incisors ; appl. bones, foramina, 
fossa, canals (anat.}. 

incisor (Insfzor) a. [L. incisus, cut 
into.] Adapted for cutting appl. 
mammalian premaxillary teeth ; n. 
a crest or ridge of bone (anat.}. 

included (inklood'e'd) a. [L. includere, 
to shut in.] Having stamens and 
pistils not protruding beyond the 
corolla ; not exserted (hot.}. 

incomplete metamorphosis, insect 
metamorphosis in which the young 
are hatched in the general adult 
form and develop without a quies- 
cent stage (zoo/.). 

incongruent (Tnkong'grooent) a. [L. 
incongruens, not suiting.] Not 
suitable or fitting ; appl. surface of 
joints which do not fit properly 

incoordination (in'koor'dina'shun) n. 
[L. in, not ; cum, together ; ordo, 
order.] Want of coordination ; 
irregularity of movement due to 
loss of muscle control (phys.}. 

incrassate (mkras'at) a. [L. incras- 
sare, to thicken.] Thickened. 

incubation (in'kuba'shun) n. [L. in- 
cubare, to lie on.] The hatching of 
eggs by means of heat, natural or 
artificial (emb.}. 

incubous (in'kubus) a. [L. incubare, 
to lie on.]. Appl. leaves so arranged 
that the base of each is covered by 
the upper portion of the next lower 

incudate (mg'kudat) a. [L. incus, 

anvil.] Appl. type of Rotifer mastax 
with large and hooked rami and 
reduced mallei (zoo/.). 

incumbent (mkum'bent) a. [L. in- 
cumbere, to lie upon.] Lying upon ; 
bent downwards to lie along a base ; 
appl. cotyledons with hypocotyl 
applied to the back (bot.} ; appl. 
hairs or spines applied lengthwise 
to their base (zoo/.). 

incurrent (inkur'gnt) a. [L. in, into ; 
currere, to run.] Leading into ; 
appl. ectoderm - lined canals of 
Sponges which admit water ; and 
inhalent siphons of Molluscs (zool.}. 

incurvate (Inkur'vat) a. [L. in, in ; 
curvus, bend.] Of a structure, 
curved inwards or bent back on 

incurvation (m'kiirva'shun) n. [L. 
in, in ; curvare, to bend.] The 
doubling back on itself of a struc- 
ture or organ, as of a spirochaete 
about to divide (zoo!.). 

incus (ing'kus) n. [L. incus, anvil.] 
Part of a Rotifer mastax ; the anvil- 
shaped ear ossicle of Mammals 

indeciduate (Tn'desid'uat) a. [L. in, 
not ; de, down ; cadere, to fall.] 
Non-caducous ; with maternal part 
of placenta not coming away at 
birth (zoo/.). 

indeciduous (Tn'desTd'uus) a. [L. in, 
not ; de, down ; cadere, to fall.] 
Persistent ; not falling off at 
maturity ; everlasting ; evergreen 

indefinite (indef'init) a. [L. in, not ; 
de, down ; finis, end.] Not limited ; 
not determinate ; of no fixed number 

indehiscent (in'dehis'ent) a. [L. in, 
not; dehiscens, gaping.] Not split- 
ting at maturity ; appl. certain fruits 

indeterminate growth, growth of 
stem, branch or shoot not limited 
or stopped by development of a 
terminal bud ; indefinite prolonga- 
tion and subdivision of an axis 

indeterminate inflorescence, 

growth of a floral axis by indefinite 
branching because unlimited by 
development of a terminal bud 





index finger, the forefinger or digit 
next to the thumb. 

indifferent (indif'e're'nt) a. [L. in, 
not ; dis, apart ; ferre, to carry.] 

indigenous (indfj'enus) a. [L. in, in ; 
gignere, to beget.] Belonging to 
the locality ; not imported (biol.). 

indirect (In'dlrgkt) a. [L. in, not ; 
directus, straightened.] Not by a 
simple method ; complicated ; appl. 
development, mitosis, selection, em- 
bryogeny (biol.). 

individual (in'divid'ual) a. [L. in, 
not ; dividuus, divisible.] Pert, a 
single example or unit, as indi- 
vidual variations of colour (biol.) ; 
n. a person or zooid of distinctive 
function of a hydrozoan colony 

individualism (m'divTd'ualizm) n. [L. ' 
in, not ; dividuus, divisible.] Sym- 
biosis in which the two parties 
together form what appears to be 
a single organism (biol.). 

indlviduation (in'divTdua'shiin), de- 
velopment of interdependent func- 
tional units, as in colony formation 

induced movement, movement dic- 
tated and influenced by external 
stimulus, as plant curvature (bot.). 

inductive stimulus, an external 
stimulus which influences the 
growth or behaviour of any organ- 
ism (biol.). 

indumentum (In'dumen'tum) n. [L. 
indumentum, covering.] The plum- 
age of birds ; a hairy covering 

induplicate (indu'plikat) a. [L. in, 
in ; duplex, double.] In vernation 
having bud-leaves bent or rolled 
without overlapping ; in aestivation 
having bud sepals or petals folded 
inwards at points of contact (bot.). 

induplicative (indu'plikatTv) a. [L. 
in, in ; duplex, double.] Appl. 
vernation or aestivation with in- 
duplicate foliage or floral leaves 
respectively (hot.}. 

indusial (indu'zlal) a. [L. induere, to 
put on.] Containing larval insect 
cases, as certain limestones (pal.) ; 
pert, the indusium (bot.). 

indusiate (indu'zfat) a. [L. indriere, 
to put on.] Having an enveloping 

case, appl. insect larvae (zool.) ; 
having an indusium (bot.). 

indusiform (mdu'ziform) a. [L. in- 
duere, to put on ; forma, shape.] 
Resembling an indusium (bot.). 

indusium (indu'zium) n. [L. induere, 
to put on.] An insect larva case 
(zool.) ; an outgrowth of plant epi- 
derm covering and protecting a 
sorus (bot.) ; the supracallosal gyrus 
of the olfactory lobe of the cere- 
brum, the indusium griseum 

induviae (indu'vie) n.plu. [L. induere, 
to put on.] Scale-leaves, or those 
which remain attached to stem 
after withering (bot.). 

induviate (indu'viat) a. [L. induere, 
to put on.] Covered with scale- 
leaves or induviae (bot.). 

inequilateral (Ine'k'wllat'e'ral) a. [L. 
in, not ; aequus, equal ; latus, side.] 
Having two sides unequal ; having 
unequal portions on either side of 
a line drawn from umbo to gape of 
a bivalve shell (zool.). 

inequilobate (ingk'wllo'bat) a. [L. in, 
not ; aequus, equal ; Gk. lobos, 
lobe.] With lobes of unequal size 

inequivalve (Tngk'wivalv) a. [L. in, 
not ; aequus, equal ; -ualvae, folding 
doors.] Having the two valves or 
halves of the shell unequal ; appl. 
Mollusca (zool.}. 

inerm (ine"rm') a. [L. in, not ; arma, 
arms.] Unarmed ; without means 
of defence and offence (biol.). 

inermous (ineYmus) ., inerm. 

inferior (mfe'rlor) a. [L. inferior, 
lower.] Appl. the lower placed of 
two, the farther down the axis ; 
growing or arising below another 
organ (bot.). 

inferoanterior (tn'fgroante'rior) a. [L. 
inferus, beneath; anterior, anterior.] 
Below and in front (biol.). 

inf erobranchiate (in'f grobrang'klat) a. 
[L. inferus, beneath ; Gk. brangchia, 
gills.] With gills under the margin 
of the mantle, as in certain Mollusca 

inferolateral (In'fe'rolat'e'ral) a. [L. 
inferus, beneath ; latus, side.] 
Below and at or towards the side 

inferomedian (in'fe"r6me'dlan) a. [L. 




inferus, beneath ; medius, middle.] 
Below and about the middle. 

inferoposterior (m'feroposte'rior) a. 
[L. inferus, beneath ; posterior, 
behind.] Below and behind. 

inferradial (in'ferra'dial) n. [L. in- 
ferus, beneath ; radius, radius.] 
The lower part of transversely bi- 
sected radials of certain fossil 
Crinoids (pal.). 

inflated (infla.'te'd) a. [L. in, into ; 
flare, to blow.] Puffed out ; dis- 
tended (bot.). 

inflected (inflek'ted) a. [L. inflectere, 
to bend in.] Curved or abruptly 
bent inwards or towards the axis 

inflexed (mflek'sd) a., inflected. 

inflorescence (m'flores'ens) n. [L. in- 
florescere, to begin to blossom.] A 
flowering or putting forth blossoms ; 
the method in which flowers are 
arranged on an axis (dot.}. 

infraaxillary (in'fraaksil'ari) a. [L. 
infra, below ; axilla, armpit.] 
Branching off below the axil (bot.). 

inftabasal (m'fraba'sal) n. [L. infra, 
below; basis, base.] One of a series 
of plates, perradial in position, 
below the basals in Crinoids (zool.). 

infrabranchial (in'frabrang'kial) a. 
[L. infra, below ; Gk. brangchia, 
gills.] Below the gills ; appl. part 
of the pallial chamber (zool.). 

infracentral (in'frasen'tral) a. [L. 
infra, below ; centrum, centre.] 
Below a vertebral centrum (zool.). 

infraclavicle (m'fraklav'ikl) n. [L. 
infra, below ; clavicula, little key.] 
A membrane bone occurring in the 
pectoral girdle of some Ganoids and 
Teleosts (zool.). 

infraclavicular (in'fraklavik'ular) a. 
[L. infra, below ; clamcula, small 
key.] Beneath the clavicle ; appl. 
branches of brachial plexus (anat.). 

infracortical (m'frakor'tlkal) a. [L. 
infra, below ; cortex, bark.] Be- 
neath the cortex (anat.). 

infracostal (in'frakos'tal) a. [L. infra, 
below ; costa, rib.] Beneath the 
ribs ; appl. muscles (anat.). 

infradentary (in'fraden'tari) a. [L. 
infra, below ; dens, tooth.] Beneath 
the dentary bone (anat.). 

infraglenoid (in'fragle'noid) a. [L. 
infra, below ; Gk. glene, socket ; 

eidos, like.] Below the glenoid 
fossa ; appl. a tuberosity (anat.). 

infrahyoid (m'frahl'oid) a. [L. infra, 
below ; Gk. hyoeides, Y-shaped.] 
Beneath the hyoid ; appl. muscles 

infralabial (in'frala'bial) a. [L. infra, 
below ; labium, lip.] Beneath the 
lower lip (anat.). 

inframarginal (in'framar'jinal) a. [L. 
infra, below ; margo, margin.] 
Under the margin, or marginal 
structure ; appl. a cerebral convolu- 
tion (anat.) ; appl. certain plates on 
the carapace of Chelonians below 
the marginals ; appl. the lower of 
two series of plates round the 
margin of stelleroid arms and 
discs (zool.). 

inframaxillary (in'framaksirarl) a. 
[L. infra, below ; maxilla, jaw.] 
Situated beneath the maxilla; appl. 
nerves (zool.). 

infraorbital (m'fraor'bital) a. [L. 
infra, below ; orbis, circle.] Be- 
neath the orbit ; appl. artery, canal, 
foramen, groove, nerve, etc. (anat.). 

infrapatellar (in'frapatel'ar) a. [L. 
infra, below ; patella, knee-cap.] 
Appl. a pad of fat beneath the 
patella (anat.). 

infrascapular (in'fraskap'ular) a. [L. 
infra, below ; scapula, shoulder- 
blade.] Beneath the scapula ; appl. 
artery (anat.). 

infraspinatous (m'fraspl'natus) a. [L. 
infra, below ; sptna, spine.] Be- 
neath the spine ; beneath the 
scapular spine ; appl. muscle, fossa 

infraspinous, infraspinatous. 

infrastapedial (in'frastape'dial) a. 
[L. infra, below ; stapes, a stirrup.] 
Beneath the stapes of the ear ; 
appl. a part of the columella 

infrasternal (tn'fraster'nal) a. [L. 
infra, below ; Gk. sternon, breast.] 
Beneath the breast-bone ; appl. 
notch at the lower end of the 
sternum (anat.). 

infratemporal (m'fratem'poral) a. [L. 
infra, below ; temporalts, tempor- 
ary.] Beneath the temporal bone ; 
appl. a crest or fossa (anat.). 

infratrochlear (m'fratrok'lear) a. [L. 
infra, below ; Gk. trochos, wheel.] 




Beneath the trochlea ; appl. a nerve 

infructescence (in'friiktSs'gns) n. [L. 
///, into ; frtictus, fruit.] An in- 
florescence matured into a fruit 

infundibular (in'fiindlb'ular) a. [L. 
infundibttlum, funnel.] Funnel- 
shaped ; appl. an abdominal muscle 
(anaf.) ; appl. a funnel-shaped 
corolla (bot.). 

infundibuliform (m'fundib'uliform) a. 
[L. infiindibuluin, funnel ; Jorma, 
shape.] Infundibular. 

infundibulum (In'fundlb'ulum) n. [L. 
infundibulum, funnel.] Any funnel- 
shaped organ or structure ; appl. 
part of the brain, of the ethmoid 
bone, of right ventricle, etc. (anaf.}; 
a cephalopod siphon ; part of a 
bird's oviduct ; the flattened 
stomach-like cavity of a Cteno- 
>hore, lying in the transverse plane 



infuscate (Infus'kat) a. [L. in, into ; 
fuscus, dark.] Tinged to appear 
dark, as insect wings (zool.). 

infusoriform (in'fuzo'riform) a. [L. 
infusus, poured into ; forma, shape.] 
Resembling an Infusorian ; appl. 
embryonic forms of some Coelenter- 
ates (zool.). 

infusorigen (m'fuzo'rijSn) n. [L. in- 
fusus, poured into; genos, offspring.] 
A gastrula-like phase in develop- 
ment of certain Mesozoa (zool.). 

ingest (inject') v. [L. ingestus, taken 
in.] To convey food material into 
the alimentary canal or food-cavity 

ingestion (injeYchon) n. [L. ingestus, 
taken in.] The swallowing or 
assumption of food-material (phys.). 

ingluvies (ingloov'iez) n. [L. inglu-vies, 
crop.] The crop of a bird ; a dila- 
tation of the oesophagus (zool.). 

inguinal (tng'gwinal) a. [L. inguen, 
the groin.] In the region of the 
groin (anaf.). 

inguinal ring, see abdominal ring. 

inguino - abdominal (Ing'gwino - ab- 
dom'inal) a. In region of abdomen 
and groin (anat.). 

inguino-crural (ing'gwlnd-kroor'al) a. 
In region of groin and leg (anat.). 

inhalent (Inha'ldnt) a. [L. in, into ; 
halare, to breathe.] Adapted for 

inspiring or drawing in, as terminal 
pores of incurrent canals in Sponges, 
or siphons in Molluscs (zool.). 

inhibition (In'hibish'on) n. [L. in- 
hibere, to prohibit.] Prohibition or 
checking of an action already 
commenced (phys.). 

inhibitory (inhTb'ftori) a. [L. inhibere, 
to prohibit.] Appl. nerves which 
control movement or secretion 

inion (fn'ion) ;/. [Gk. inion, back of 
head.] The external protuberance 
of the occipital (anaf.). 

ink sac, in Sepia, a pear-shaped 
body in the wall of the mantle 
cavity which secretes a black sub- 
stance, ink or sepia, the ejection of 
which is a means of defence (zool.). 

innate (In'nat) a. [L. in, in ; gnatus, 
born.] Basifixed ; appl. anther 
when filament is only attached to 
its base (bot.). 

innervation (in'nerva'shun) n. [L. 
in, into ; neruus, sinew.] Nerve- 
distribution (anaf.) ; vital nerve 
force (phys.). 

innominate (Innom'Tnat) a. [L. in, 
not ; nomen, name.] Nameless ; 
appl. various arteries and veins 

innominate bone, the hip-bone or 
lateral half of the pelvic girdle 

innovation (in'dva'shun) n. [L. inno- 
vare, to renew.] A growth or shoot 
of Mosses which develops into a 
new plant by the dying-off of the 
portion of the parent-plant behind 
it (bot.). 

inocular (Tnok'ular) a. [L. in, into ; 
oculus, eye.] Appl. antennae in- 
serted close to the eye (zool.). 

inogen (I'nojen) n. [Gk. is, fibre ; 
genos, offspring.] A nitrogenous 
substance of muscle tissue (phys.). 

inotagmata (Tnotag'mata) n. plu. 
[Gk. is, fibre ; tagma, arrangement.] 
Ultimate hypothetical units (phys.). 

inquiline (m'kwilin) n. [L. inquilinus, 
tenant.] An animal living in the 
home of another and getting share 
of its food ; a partner in com- 
mensal ism (zool.). 

inscriptions, tendinous, term appl. 
three fibrous bands crossing the 
rectus abdominalis muscle (anat.). 




insectivorous (in'sekttv'orus) a. [L. 
insectus, cut off ; -vorare, to devour.] 
Insect-eating ; appl. certain animals 
and carnivorous plants. 

inserted (insgr'tgd) a. [L. in, in ; 
serere, to join.] United by natural 

insertion (insSr'shun) n. [L. insertus, 
joined.] Point of attachment of 
organs, muscles ; the point on 
which the force of a muscle is 
applied (anat.}. 

insessorial (m'sgso'rial) a. [L. in, in ; 
sedere, to sit.] Adapted for perch- 
ing (zool.}. 

insistent (insis'tgnt) a. [L. insistere, 
to persist.] Appl. hind toe of 
certain birds whose tip only reaches 
the ground (sool.}. 

inspiration (inspira'shun) n. [L. in- 
spirare, to inhale.] The act of 
drawing air into the lungs 

instaininate (mstaminat) a. [L. tn, 
not ; stamen, something standing.] 
Not bearing stamens (hot.). 

instar (in'star) n. [L. instar, form.] 
Each stage in insect metamorphosis 
where a moult occurs (zool.}. 

insula (in'sula) n. [L. insula, island.] 
A triangular eminence lying deeply 
in the lateral fissure of the temporal 
lobe (anat.}. 

integrifolious (intgg'rifo'lms) a. [L. 
integer, whole ; folium, leaf.] With 
entire leaves (bot.}. 

integripallial (mtgg'ripal'ial) a. See 

integripalliate (integ'ripa.riat) a. [L. 
integer, whole ; pallium, mantle.] 
Having an unbroken pallial line ; 
appl. shells of Molluscs with small 
or no siphons (zool.}. 

integument (mtgg'umgnt) n. [L. 
integumentum, covering.] A cover- 
ing, investing, or coating structure 
or layer ; an investing layer of an 
ovule (hot., zool.}. 

Interacinous (in'tgras'fnus) a. [L. 
inter, between ; acinus, a grape.] 
Among the alveoli of a racemose 
gland (anat.}. 

interalveolar (in'tgralve'olar) a. [L. 
inter, among ; alveolus, small 
cavity.] Among alveoli ; appl. cell 
islets (anat.}. 

interamtoulacral (in'tgrambula'kral) a. 

[L. inter, between ; ambulare, to 
walk.] Appl. area of echinoderm 
test between two ambulacral areas ; 
n. a plate of that area (zool.}. 

n. [L. inter, between ; ambulare, 
to walk.] The area between two 
ambulacral areas (zool.}. 

interarticular (m'terartik'ular) a. [L. 
inter, between ; articulus, a joint.] 
Between articulating parts of bones; 
appl. certain ligaments and fibro- 
cartilages (anat.}. 

interatrial (in'tgra'trial) a. [L. inter, 
between ; atrium, a hall] Appl. a 
groove separating the two atria of 
the heart (anat.}. 

interauricular (in'terorik'ular) a. [L. 
inter, between ; auricula, little ear.] 
Between the auricles of the heart 

interaxillary (in'tgraksil'ari) a. [L. 
inter, between ; axilla, armpit.] 
Placed between the axils (hot.}. 

interbrachial (in'tgrbra'kial) a. [L. 
inter, between ; brachium, arm.] 
Between arms, rays, or brachial 
plates (zool.}. 

interbranchial (in'tgrbrang'klal) a. 
[L. inter, between ; Gk. brangchia, 
gills.] Appl. septum between suc- 
cessive gill slits (zool.}. 

interbreed (in'tgrbred') v. [L. inter, 
between ; A.S. brod, brood.] To 
cross different varieties of plants 
or animals experimentally. 

intercalare (in'tgrkala're, -kalara) . 
[L. intercalaris, inserted.] In many 
Fishes and fossil Amphibia, an 
additional element in the neural 
arch (zool.}. 

intercalary (m'tgrkal'ari, intgr'kalari) 
a. [L. intercalaris, inserted.] Ad- 
ditional ; appl. meristematic layers 
between masses of permanent 
tissue ; growth elsewhere than at 
the growing point (bot.}. 

intercapitular (in'terkapit'ular) a. [L. 
inter, between ; capitulum, head.] 
Between the capitula ; appl. veins 
of fingers (anat.}. 

intercarotid (m'terkarot'id) a. [L. 
inter, between ; Gk. karos, deep 
sleep.] Between the two carotid 
arteries (anat.}. 

intercarpal (m'tgrkar'pal) a. [L. inter, 
between ; carpus, wrist.] Among 




or between the carpal bones ; appl. 
joints (anat.}. 

intercarpellary (tn'tgrkarpgl'arl) a. 
[L. infer, between ; Gk. karpos, 
fruit.] Between the carpels (dot.}. 

intercartilaginous (Tn'tgrkartilaj'inus) 
a. [L. inter, between ; cartilago, 
gristle.] Within the cartilage ; 
appl. ossification (emb.}. 

intercavernous (in'tgrkaVgrnus) a. 
[L. inter, between ; cavus, hollow.] 
Appl. sinuses connecting the cav- 
ernous sinuses, part of the ophthal- 
mic veins (anat.}. 

intercellular (in'tgrsgl'ular) a. [L. 
inter, between ; cellula, little cell.] 
Among or between cells, as the 
biliary passages among the liver- 
cells (anat.}. 

Intercentral (m'tgrsgn'tril) a. [L. 
inter, between ; centrum, centre.] 
Uniting two centra ; between two 
centra (anat.}. 

inter-centrum (In'tgrsgn'trum) n. [L. 
inter, between ; centrum, centre.] 
A second central ring in an embo- 
lomerous vertebra (zool.}. 

interchondral (In'tSrkon'dral) a. [L. 
inter, between ; Gk. chondros, carti- 
lage.] Appl. articulations and 
ligaments between the costal carti- 
lages (anat.}. 

interclavicle (m'tgrklav'ikl) n. [L. 
inter, between ; clavicula, small 
key.] The episternum ; a median 
ventral bone between the clavicles 

interclavicular (m'tgrklavlk'ular) a. 
[L. inter, between ; clavicula, small 
key.] Between the clavicles ; appl. 
a ligament (anat.}. 

interclinoid (m'tgrkll'noid) a. [L. 
inter, between ; Gk. kline, bed ; 
eidos, like.] A fibrous process 
joining the anterior and posterior 
clinoid processes (anat.}. 

intercolumnar (m'tgrk61um'nar)<z. [L. 
inter, between ; columna, column.] 
Between columnar structures, as 
certain abdominal muscle fibres 

intercondyloid (in'tgrkon'dlloid) a. 
[L. inter, between ; Gk. kondylos, 
knob ; eidos, resemblance.] Be- 
tween the condyles ; appl. an 
eminence of the tibia, and fossae 
of the femur (anat.}. 

intercostal (In'tgrkos'tal) a. [L. inter, 
between ; costa, rib.] Between the 
ribs, as arteries, glands, membranes, 
nerves, veins, muscles (anat.}. 

intercostobrachial (m'tgrkSs'tobra'- 
kial) a. [L. inter, between ; costa, 
rib ; brachium, arm.] Appl. a 
lateral branch of the second inter- 
costal nerve which supplies the 
upper arm (anat.}. 

intercostohumeral (m'tgrkSs'tohu'- 
mgral) a. [L. inter, between ; costa, 
rib ; humerus, the humerus.] Inter- 

intercoxal (in'tgrkSk'sal) a. [L. inter, 
between ; coxa, the hip.] Between 
the coxae or first-limb joints of 
Arthropods (zool.}. 

intercrescence (In'tgrkrgs'gns) n. [L. 
inter, between ; crescere, to grow.] 
A growing into each other, as of 

intercrural (in'tgrkroo'rSl) a. [L. 
inter, between ; crus, the leg.] 
Appl. tendinous fibres arching 
across the external oblique muscles 

intercuneiform (in'tgrkune'iform) a. 
[L. inter, between ; cuneus, wedge ; 
forma, shape.] Connecting the three 
cuneiform bones of the ankle ; appl. 
articulations and ligaments (anat.}. 

interdeferential (In'tgrdgfgr'gn'shal) 
a. [L. inter, between ; de, down ; 
ferre, to carry.] Between the vasa 
deferentia (zool.}. 

interfascicular(in'tgrfasTk'ular) a. [L. 
inter, between ; fasciculus, small 
bundle.] Situated between the 
fascicles or vascular bundles (hot.}. 

interfemoral (m'tgrfgm'oral) a. [L. 
inter, between ; femur, thigh bone.] 
Between the thighs (anat}. 

interfertile (In'tgrfgr'til) a. [L. inter, 
between ; fertilis, fertile.] Able to 
interbreed (biol.}. 

interfllamentar (in'tgrfilamgn'tar) a. 
[L. inter, between ; filamentum, 
thread.] Appl. junctions or hori- 
zontal bars connecting molluscan 
gill filaments (zool.}. 

interfllar (Tn'tgrfflar) a. [L. inter, 
between ; filum, thread.] Appl. 
the ground substance of proto- 
plasm, as opposed to the reticular 


interfoliaceous (m'tgrfolla'shus) a. 




[L. inter, between ; folium, leaf.] 
Situated or arising .between two 
opposite leaves (hot.). 

interfoliar (In'terfo'liar) a. Inter- 

interganglionic (in'te"rganggli6n'ik) a. 
[L. inter, between ; Gk. gangglion, 
a little tumour.] Connecting two 
ganglia, as nerve cords or strands 

intergenital (Tn'terjen'ital) a. [L. 
inter, between ; genitus, produced.] 
Between the genitals ; appl. certain 
echinoderm plates (zool.). 

interglobular (m'terglob'ular) a. [L. 
inter, between ; globulus, small 
globe.] Appl. a series of spaces 
towards the outer surface of den- 
tine due to imperfect calcification 

intergular (m'tergu'lar) n. [L. inter, 
between ; gula, gullet.] A paired 
or unpaired plate in front of the 
gulars in Chelonia (zool.). 

interhyal (in'tgrhl'al) n. [L. inter, 
between ; Gk. hyoeides, Y-shaped.] 
A small bone between hyomandib- 
ular and rest of hyoid of some 
higher vertebrates (zool.). 

interlamellar (In'terlameTar) a. [L. 
inter, between ; lamella, a plate.] 
Appl. vertical bars of tissue joining 
the gill lamellae of Molluscs (zool?). 

interlaminar (in'terlam'mar) a. [L. 
inter, between ; lamina, plate.] 
Uniting laminae ; between laminae 

interlobular (in'tgrlob'ular) a. [L. 
inter, between; lobus, lobe.] Occur- 
ring between lobes ; appl. kidney 
arteries, etc. (anat.}. 

interlocular (in'tSrlok'ular) a. [L. 
inter, between; loculus, small place.] 
Between the loculi (bot.). 

interloculus (in'tgrlSk'ulus) n. [L. 
inter, between ; loculus, compart- 
ment.] The space between two 
loculi (bot.). 

intermandibular (m'tgrmandib'ular) 
a. [L. inter, between ; mandibu- 
lum, jaw.] Between mandibles or 
rami (anat.). 

Intermaxllla (m'tgrmaksll'a) n. [L. 
inter, between ; maxilla, jaw.] 
Bone between the maxillae ; the 
premaxilla (anat.). 

Intermaxillary (in'termaksll'ari) a. 

& inter, between ; maxilla, jaw.] 
tween the maxillae ; pert, the 
premaxillae ; appl. a gland in the 
nasal septum of certain Amphibians 
and Reptiles (zool.). 

intermediary (in'terme'diari) a. [L. 
inter, between ; medius, middle.] 
Acting as a medium ; appl. nerve- 
cells receiving impulses from affer- 
ent cells and transmitting them to 
efferent cells (phys.)._ 

intermediate (in'terme'diat) a. [L. 
inter, between ; medius, middle.] 
Occurring between two points or 
parts ; appl. a nerve-mass (emb.) ; 
appl. certain areas of the brain 
(phys.) ; appl. a disc in striated 
muscle (anat.). 

intermediate host, the host inter- 
vening between two others in the 
life-history of certain parasites, 
as Limnaeus in the life-history of 
Distomum (zool.). 

intermedium (in'terme'dlum) n. [L. 
inter, between ; medius, middle.] 
A small bone of carpus and tarsus 

intermesenteric (In't6rmgs'6nt6r'lk) a. 
[L. inter, between ; Gk. mesos, 
middle ; enteron, gut.] Occurring 
between the mesenteries ; appl. 
spaces between the mesenteries in 
sea-anemones (zool.). 

intermuscular (m'terinus'kular) a. 
[L. inter, between ; musculus, 
muscle.] Between or among muscle 
fibres (anat.). 

internal (inteVnal) a. [L. internus, 
within.] Located on the inner side ; 
nearer the middle axis (biol.). 

internal secretion gland, a duct- 
less gland, e.g. spleen (phys.). 

internasal (in'te'rna'zal) a. [L. inter, 
between ; nasus, nose.] Between 
the nostrils ; appl. septum, gland 

interneural (m'tgrnu'ral) a. [L. inter, 
between ; Gk. neuron, nerve.] Be- 
tween neural processes, arches or 
spines (anat.) ; appl. sharp bones 
attached to dorsal fin rays (zool.). 

internodal (m'terno'dal) a. [L. inter, 
between ; nodus, knot.] Pert, the 
part between two nodes (hot., phys.). 

internode (in'ternod') n. [L. inter, 
between ; nodus, knot.] A structure 
between two nodes or joints ; as of 




a stem (bot.), of a nerve fibre 

internodia (Tn't6rno'dia) n.plu. Phal- 

interocular (in'tgrok'ular) a. [L. inter, 
between ; oculus, eye.] Placed 
between the eyes (zool.). 

interopercle ( In'tgropeYkl) n. [L. 
inter, between ; operculum, lid.] A 
membrane bone of the operculum 
of Teleostomes attached to the 
mandible (zool.). 

interopercular bone, the interoper- 


interoptic (Tn'tgrop'tik) a. [L. inter, 
between ; Gk. optikos, pert, sight.] 
Between the optic lobes (anat.). 

interorbital (in'tgror'bital) a. [L. 
inter, between ; orbis, circle.] Be- 
tween the orbits ; appl. septum of 
a trophibasic skull ; appl. sinus 

Jnterosculant (Tn'teros'kulant) a. [L. 
inter, between ; osculari, to kiss.] 
Possessing characters common to 
Iwo or more groups or species 

interosseous (Tn'teros'eiis) a. [L. inter, 
between ; os, bone.] Occurring 
between bones ; appl. arteries, 
membranes, muscles, nerves (anat.). 

interparietal (in'tgrparfe'tal) a. [L. 
inter, between ; paries, wall.] In 
many vertebrates a bone arising 
between the parietals and supra- 
occipital (anat.). 

interpeduncular (In'tSrpSdung'kular) 
a. [L. inter, between ; pedunctilus, 
little foot.] Appl. a fossa between 
the cerebral peduncles ; and also 
a ganglion (anat.). 

Interpetaloid (in'terpeYaloid) a. [L. 
inter, between ; Gk. petalon, petal ; 
eidos, resemblance.] Between the 
petaloid areas of an echinoderm 
test (zool.}. 

interpetiolar (m't6rp6t'idlar) a. [L. 
inter, between ; petiolus, little foot.] 
Situated between the petioles or 
bases of opposite leaves (bot.). 

interphalangeal (in'tgrfalan'jeal) a. 

fL. inter, between ; Gk. phalanx:, 
ine of battle.] Appl. articulations 
between successive phalanges 

interplacental (Tn'tgrplasgn'tal) a. [L. 
inter, between ; placenta, flat plate.] 
Between placentae (dot.}. 

interpleural (m'te'rploo'ral) a. [L. 
inter, between ; Gk. pleuron, side.] 
Between pleurae (anat.}. 

interpubic (Tn'tgrpu'bik) a. [L. inter, 
between ; piibis^ mature.] Appl. the 
fibrocartilaginous lamina between 
the pubic bones (anat.}. 

interradial (in'tgrra'dlal) a. [L. inter, 
between ; radius, radius.] Pert. 
an interradius (zool.}. 

interradium (in'tgrra'dlum) n. [L. 
inter, between; radius, radius.] The 
area between two radii of any 
radially symmetrical animal (zool.}. 

interradius (in'tgrra'dius) n. [L. inter, 
between ; radius, radius.] The 
radius of a radiate animal halfway 
between two perradii (zool.}. 

interramal (Tn'te'rra'mal) a. [L. inter, 
between; ramus, branch.] Between 
branches or rami (biol.\ 

interramicorn (m'tgrram'ikorn) n. [L. 
inter, between ; ramus, branch ; 
cornu, horn.] A piece of a bird's 
bill beyond the mandibular rami 
forming the gonys (zool.}. 

interrenal (in'tgrre'nal) a. [L. inter, 
between ; renes, kidneys.] Between 
the kidneys ; appl. veins and ad- 
renal organs of uncertain function 
in most vertebrates (zool.}. 

interrupted (in'tgrrup'ted) a. [L. 
inter, between ; rumpere, to break.] 
Unsymmetrical ; with continuity 
broken ; irregular (hot.}. 

interruptedly pinnate, pinnate with 
pairs of small leaflets occurring 
between larger ones (dot.). 

interscapular (Tn'tgrskap'ular) a. . [L. 
inter, between ; scapula, shoulder- 
blade.] Between the shoulder- 
blades ; appl. feathers (zool.). 

interseptal (Tn't6rs6p'tal) a. [L. inter, 
between ; septum, division.] Pert. 
spaces between septa or partitions. 

interspicular (in'tgrspik'ular) a. [L. 
inter, between ; spiculum, sharp 
point.] Occurring between spic- 
ules (zool.). 

interspinal (in'tgrsprnal) a. [L. inter, 
between ; spina, spine.] Occurring 
between spinous processes or be- 
tween spines ; appl. bones, muscles 




interspinous (in'tgrspl'nus) a. Inter- 

interstapedial (in'tgrstape'dial) a. [L. 
inter, between ; stapes, stirrup.] 
Appl. a part of the columella of the 
ear (anat.). 

intersterility (m'tgrsteril'iti) n. [L. 
inter, between ; sterilis, unfruitful.] 
Incapacity for interbreeding (biol.). 

intersternal (in'tgrsteYnal) a. [L. 
inter, between ; Gk. sternon, breast- 
plate.] Between the sterna (zool.); 
appl. ligaments connecting the 
manubrium and body of sternum 

interstitial (m'tgrstish'al) a. [L. 
inter, between ; sistere, to set.] 
Occurring in interstices or spaces ; 
appl, cells within tissues. 

Intel-temporal (m'tgrtgm'poral) n. [L. 
inter, between ; temporalis, tempo- 
rary.] A paired membrane bone, 
part of the sphenoid complex, fusing 
with the alisphenoids (zool.). 

intertentacular (in'te'rte'ntak'ular) a. 
[L. inter, between ; tentaculum, a 
feeler.] Between the tentacles ; 
appl. a ciliated tube opening at the 
base of the tentacles and connect- 
ing coelom and the exterior, found 
in the Molluscoida (zool.). 

intertidal (in'tferti'dal) a, [L. inter, 
between ; A.S. tid, time.] Appl. 
shore animals and plants living 
between high- and low-water 
marks (biol.). 

intertrochanteric (m'tgrtrokanteVik) 
a. [L. inter, between ; Gk. tro- 
chanter, a runner.] Between the 
trochanters ; appl. crest, and line 

intertrochlear (in'tertrok'lear) a. [L. 
inter, between ; Gk. trochos, wheel.] 
Appl. an ulnar ridge fitting into a 
groove of the humerus (anat.). 

interventricular (in'tgrvgntrik'ular) a. 
[L. inter, between ; ventricula, small 
cavity.] Between the ventricles ; 
appl. a foramen (anat.). 

intervertebral (in'tervgr'tgbral) a. 
[L. inter, between ; vertebra, 
vertebra.] Occurring between the 
vertebrae ; appl. fibrocartilages, 
foramina, veins, discs (anat.). 

intervillous (in'tgrvil'us) a. [L. inter, 
between ; villi, hairs.] Appl. the 
spaces in the trophoblastic network 

filled with maternal blood (smb.} ; oc- 
curring between villi (anat., zool). 

interzonal (m'tgrzo'nal) a. [L. inter, 
between ; zona, belt.] Between two 
zones ; appl. spindle fibres uniting 
groups of daughter chromosomes 
in the anaphase of mitosis (cyt.). 

interzooecial (in'tgrzoe'shial) a. [L. 
inter, between ; zoon, animal ; oikos, 
house.] Occurring among zooecia 

intestinal (intgs'tinal) a. [L. in- 
testinus, internal.] Pert, the in- 
testines; appl.< arteries, glands, villi, 
etc. (anat.). 

intestine (intgs'tin) n. [L. intestinus, 
internal.] That part of the ali- 
mentary canal from pylorus to 
anus, or the part corresponding to 
this in lower forms (zool.). 

intextine (intek'stin) n. [L. intus, 
within ; exter, without.] An inner 
membrane of an extine (bot.\ 

intima (m'tima) n. [L. intimus, inner- 
most.] The innermost lining mem- 
brane of a part or organ (anat."). 

intine (in'tin) n. [L. intus, within.] 
The inner covering membrane of a 
pollen grain (bot.}. 

intrabiontic (Tn'trablon'tik) a. [L. 
intra, within ; Gk. bios, life ; on fa, 
beings.] Appl. a process of selec- 
tion occurring in a living unit 
(phys., biol.). 

intracapsular (m'trakap'sular) a. [L. 
intra, within ; capsula, small chest.] 
Contained within a capsule, as the 
protoplasm of Radiolarians (biol.). 

intracardiac (Tn'trakar'diak) a. [L. 
intra, within ; Gk. kardia, heart.] 
Within the heart (zool., anat.}. 

intracartilaginous (Tn'trakar'tilaj'- 
inus) a. [L. intra, within ; cartilage, 
gristle.] Inside the cartilage ; appl. 
ossification (emb.). 

intracellular (in'trasgl'ular) a. [L. 
intra, within ; cellula, little cell.] 
Within the cell (biol., phys.). 

intracortical (in'trakor^tikal) a. [L. 
intra, within ; cortex, rind.] Uniting 
parts of the brain cortex, or within 
it (anat.). 

intrafascicular (in'trafasTk'ular) a. 
[L. intra, within ; fasciculus, little 
bundle.] Within a vascular bundle 

intrafoliaceous (m'trafolia'shus) a. 




[L. intra, within ; folium, leaf.] 
Appl. stipules encircling the stem 
and forming a sheath ; cf, ochrea 

Intrafusal (m'trafu'sal) a. [L. infra, 
within ; fusus, poured.] Appl. 
fasciculi and fibres connected re- 
spectively with neurotendinous and 
neuromuscular spindles (anat.}. 

intraglobular (in'traglob'ular) a. [L. 
intra, within ; globus, globe.] Oc- 
curringwithin aglobule or corpuscle 

intrajugular (in'trajoog'ular) a. [L. 
infra, within ; jugulum, throat.] 
Appl. a bony spicule or process in 
the middle of the jugular notch 

intralamellar (Tn'tralamel'ar) a. [L. 
intra, within ; lamella, thin plate.] 
Within a lamella ; afipl. the trama 
of gill-bearing Fungi (bot.}. 

intralobular (in'tralob'ular) a. [L. 
intra, within ; lobulus, small lobe.] 
Occurring within lobules ; appl. 
veins draining the liver lobules 

a. [L. intra, within ; membrana, 
film.] Appl. bone developed in 
membrane (anat.}. 

intramolecular (m'tramolgk'ular) a. 
[L. intra, within ; F. molecule, small 
particle.] Appl. plant respiration 
from the splitting up of complex 
substances within the cell (bot.}. 

intranuclear (in'tranu'klear) a. [L. 
intra, within ; nucleus, kernel.] 
Within the nucleus ; appl. spindles, 
fibres, etc. (cyt.}. 

intraparietal (in'trapari'e'tal) a. [L. 
intra, within ; paries, wall.] En- 
closed within the walls of an organ ; 
within the parietal lobe, as sulcus, 
fissure, etc. (anat.}. 

intrapetalous (In'trapgt'alus) a. [L. 
intra, within ; Gk. petalon, petal.] 
Situated in a petaloid area, in 
Echinoderms (zool.}. 

intrapetiolar (m'trapgt'iolar) a. [L. 
intra, within ; petiolus, little foot.] 
Within the petiole base expansion 

intrapleural (in'traploo'ral) a. [L. 

intra, within ; Gk. pleuron, side.] 

Within the thoracic cavity. 

intraselection (In'traseWshun) 

[L. intra, within ; selectus, chosen.] 
Selection within an organ of cells 
fittest to survive. 

intrastelar (in'traste'lar) a. [L. intra, 
within ; stele, pillar.] Within the 
stele of a stem or root ; appl. 
ground tissue, bundles, etc. (bot.}. 

intratarsal (in'tratar'sal) a. [L. intra, 
within ; tarsus, ankle.] Within the 
tarsus ; appl. joint of reptilian limb 
between the rows of tarsal bones 

intrathyroid (In'trathl'roid) a. [L. 
intra, within ; Gk. thyreos, shield ; 
eidos, like.] Appl. a cartilage join- 
ing the laminae of the thyroid 
cartilage during infancy (anat.}. 

intrauterine (In'trau't6rin) a. [L. 
intra, within ; uterus, womb.] De- 
veloping or passed within the 
uterus (emb.}. 

intravaginal (in'travaj'inal) a. [L. 
intra, within ; vagina, sheath.] 
Within the vagina (zool.} ; con- 
tained within a sheath, as grass 
branches (bot.}. 

intravascular (m'travaVkular) a. [L. 
intra, within ; vasculum, small 
vessel.] Within the blood-vessels 

intraventricular (m'travgntrik'ular) 
a. [L. intra, within ; ventriculus, 
small cavity.] Appl. the caudate 
nucleus of the corpus striatum, 
seen within the ventricle of the 
brain ; within a ventricle (anat.}. 

intravesical (m'traves'ikal) a. [L. 
intra, within ; vesica, bladder.] 
Within the bladder (anat.}. 

intravitelline (in'travitglfn) a. [L. 
intra, within ; vitellus, egg-yolk.] 
Within the yolk of an egg (emb.}. 

intraxylary (in'trazl'lari) a. [L. 
intra, within ; Gk. xylon, wood.] 
Within the wood or xylem (bot.}. 

intrinsic (mtrm'sik) a. [L. intrinsecus, 
inwards.] Appl. inner muscles of 
tongue ; opp. extrinsic (anat.}. 

introitus (Intro'itus) n. [L. intro, 
within ; ire, to go.] An opening 
or orifice (anat.}. 

intromittent (In'tromit'fint) a. [L. 
intro, within ; mittere, to send.] 
Adapted for inserting ; appl. male 
copulatory organs (zool.}. 

introrse (Intr&rs') a. [L. intro, within ; 

n. versus^ turned.] Turned inwards 




or towards the axis ; of anthers, 
opening on the side next the 
pistil (60 f.). 

Introvert (m'trovert) n. [L. intro, 
within ; vertere, to turn.] That 
which is capable of involution, as 
the anterior region of the body of 
certain zooids, of certain Annulates, 
the mouth extremity of certain 
Molluscs (zool.} ; v. to turn, bend, 
or draw inwards (biol.). 

Intussusception (m'tussusgp'shun) n. 
[L. intus, within ; suscipere, to 
receive.] Growth in surface-extent 
or volume by intercalation of par- 
ticles among those already present 

inulase (in'ulas) n. [L. inula, the 
plant elecampane.] A ferment of 
plants which acts on inulin (bat.). 

inulin (m'ulin) n. [L. inula, the plant 
elecampane.] A form of starch 
found in plant-cell sap (bot.). 

invaginate (mvaj'inat) v. [L. in, 
into ; vagina, sheath.] To involute 
or draw into a sheath ; appl. the 
insinking of a wall of a cavity or 
vessel apparently reducing the 
original cavity and leaving a new 
cavity or groove visible on the 
exterior {zool., bot.). 

invagination (invaj'ina'shun) n. [L. in, 
into ; vagina, sheath.] Involution ; 
introversion ; gastrula-formation by 
infolding of the blastula wall (zool.}. 

invertase (inveVtas) n. [L. invertere, 
to turn into.] A ferment of plants 
which acts on cane sugar (bot.). 

invertebrate (invgr'tgbrat) a. [L. in, 
not ; vertebra, joint.] Back-bone- 
less ; without spinal column. 

investing bones, membrane bones. 

investment (mv&st'ment) n. [L. in, 
in ; vestire, to clothe.] The outer 
covering of a part, organ, animal, 
or plant. 

involucel (invol'use'l) n. [Dim. of L. 
involucrum, covering.] The small 
bracts at the base of a secondary 
umbel ; a partial involucre (hot.}. 

involucellate (Invol'usSl'at) a. [Dim. 
of L. involucrum, covering.] Bear- 
ing involucels (bot.). 

involucral (in'volu'kral) a. [L. in- 
volucrum, covering.] Pert, or like 
an involucre (bot.). 

involucrate (m'volu'krat) a. [L. in- 

volucrum, covering.] Bearing in- 
volucres (bot.). 

involucre (in'volu'ker) n. [L. invo- 
lucrum, covering.] Bracts at the 
base of chief branches of compound 
umbels (bot.). 

involucrum (in'volu'krum) n. [L. 
involucrum, covering.] In Hydro- 
medusae, the protective cup into 
which nematocysts can be spirally 
retracted ; the metanotum of Or- 
thoptera (zool.) ; an involucre (hot.). 

involuntary (invol'untarl) a. [L. in, 
not ; voluntas, a wish.] Not under 
control of the will ; appl. certain 
plain unstriped muscles, as of the 
alimentary canal, and to their 
movements (phys.). 

involute (in'volut) a. [L. involutus, 
rolled up.] Of leaves, having the 
edges rolled inwards at each side 
(bot.) ; of shells, closely coiled 

involution (in'volu'shun) n. [L. in- 
volvere, to roll up.] Appl. forms 
that have become deformed in 
structure owing to unfavourable 
conditions, but not to such an 
extent as to be incapable of re- 
covery if the conditions improve ; 
as the so-called "latent bodies" in 
the Haemoflagellate life - history 

iodothyrin (lo'dothl'nn) n. [Gk. iodes, 
violet ; thyreos, shield.] An iodine 
compound in the colloid material 
of the thyroid gland (phys.). 

iridial angle, the filtration angle of 
the eye ; an angular recess at the 
anterior surface of the attached 
margin of the eye (anat.). 

iridocytes (ir'idoslts) n. plu. [L. iris, 
rainbow; Gk. kytos, hollow.] Guanin 
granules, bodies or plates, of which 
the reflecting tissue of the skin of 
Fishes is composed ; iridescent 
cells in the integument of Sepia 

iridomotor (ir'idomo'tor) a. [L. iris, 
rainbow ; movere, to move.] Con- 
nected with the movements of the 
iris (phys.). 

iris (I'ris) n. [L. iris, rainbow.] A 
thin, circular, contractile disc sus- 
pended in the aqueous humour of 
the eye between the cornea and 
lens (anat.). 




irritability (ir'itabil'itl) n. [L. irritare, 
to provoke.] Power of receiving 
external impressions or stimuli, and 
reacting to them, inherent in living 
matter (phys.). 

irritant (Ir'itant) n. [L. irritare, to 
provoke.] An external stimulus 
which provokes a response (phys.). 

ischiadic (is'kTad'lk) a. Ischial. 

ischial (Ts'kial) a. [Gk. ischion, a hip.] 
Pert, or in the region of the hip ; 
appl. artery, vein (anat.). 

ischiocapsular (Ts'kTokap'sular) a. 
[Gk. ischion, hip ; L. capsula, little 
chest.] Appl. a ligament joining 
the capsular ligament and the hip 

ischiocavernous (Ts'kTokav'ernus) a. 
[Gk. ischion, hip ; L. cavus, hollow.] 
Appl. muscle between the hip and 
the corpora cavernosa (anat.). 

ischiopodite (fs'kiop'odlt) n. [Gk. 
ischion, hip ; pous, foot.] The 
proximal joint of the walking legs 
of certain Crustacea, or of the 
maxillipedes (zool.). 

ischiopubic (Is'kTopu'bTk) a. [Gk. 
ischion, hip ; L. pubis, adult.] Appl. 
a gap or fenestra between the 
ischium and pubis (anat.). 

ischiopubis (Ts'kTopu'bTs) n. [Gk. 
ischion, hip ; L. pubis, adult.] The 
ischium of Pterodactyls, the pubis 
being excluded from the acetabu- 
lum ; a fused ischium and pubis 

ischiorectal (Is'kTorgk'tal) a. [Gk. 
ischion, hip ; L. rectus, straight.] 
Pert, ischium and rectum ; appl. 
fossa and muscles (anat.). 

ischium (Ts'kTum) n. [Gk. ischion, 
hip.] The ventral and posterior 
bone of each half of the pelvic 
girdle of Mammals ; an ischiopodite 

isidiferous (I'sTdif'erus) a. [Gk. isis, 
plant ; ~L.ferre, to bear.] Bearing 
isidia (bot.). 

isidioid (IsTd'Toid) a. [Gk. isis, plant ; 
cidos, like.] Like an isidium (bot.). 

isidium (IsTd'ium) ., isidia (Isid'ia) 
plu. [Gk. isis, plant.] Coral-like 
soredia on the surface of some 
Lichens (bot.). 

isidophorous (I'sTdof'oriis) a. [Gk. 
isis, plant ; pherein, to bear.] Isid- 

islets of Langerhans, spherical or 
oval bodies scattered throughout 
the pancreas, concerned in the 
metabolism of sugar in the body 

isobilateral symmetry, the quality 
of leaves whose upper and lower 
surfaces are similar (dot.). 

isocarpous (I'sokar'pus) a. [Gk. isos, 
equal ; karpos, fruit.] Having car- 
pels and perianth divisions equal 
in number (bot.). 

isocercal (I'soseYkal) a. [Gk. tsos, 
equal ; kerkos, tail.] With verte- 
bral column ending in median line 
of caudal fin (zool.). 

isochela (I'soke'la) n. [Gk. isos, equal ; 
chele, claw.] A chela with two 
parts equally developed (zool.). 

isocytic (I'sosTt'ik) a. [Gk. isos, equal ; 
kytos, hollow.] With all cells equal 

isodactylous (I'sodak'tiliis) a. [Gk. 
isos, equal; daktylos, finger.] Hav- 
ing all the digits of equal size 

isodiametric (I'sodiamgt'rik) a. [Gk. 
t'sos, equal ; dia, through ; metron, 
measure.] With cells or other 
structures of equal diameter (bot.). 

isodont (I'so'dont) a. [Gk. isos, equal ; 
odous, tooth.] Having teeth all 
equal (zool.). 

isodynamic (I'sodtnam'ik) a. [Gk. 
isos, equal ; dynamis, power.] Of 
equal strength ; appl. foods (phys.). 

isogamete (I'sogamet') n. [Gk. isos, 
equal ; gamos, marriage.] One of 
a pair of equal gametes, not 
differentiated from one another. 

isogamous (Isog'amus) a. [Gk. isos^ 
equal ; gamos, marriage.] Having 
the gametes alike (hot.). 

isogamy (isog'amT) n. [Gk. isos, 
equal ; gamos, union.] Sexual 
union, or union of similar gametes 

isogenetic (I'sojengt'ik) a. [Gk. isos, 
equal ; genos, offspring.] Arising 
from the same or a similar origin 

isogenous (isoj'e'nus) a. Isogenetic. 

isognathous (Isog'nathus) a. [Gk. 
isos, equal; gnathos, jaw.] Having 
both jaws alike (zool.). 

isomastigote (I'somas'tTgot) a [Gk. 
isos, equal; inastix, whip.] Having 




the flagella of equal length 

isomere (I'somer) n. [Gk. isos, equal; 
meros, part.] A homologous struc- 
ture or part (zool.). 

isoinerous (Isom'Srus) a. [Gk. isos, 
equal; meros, part.] Having equal 
numbers of different parts ; appl. 
flowers with the same number of 
parts in each whorl (dot.). 

isomorphic (I'somor'fik) a. [Gk. isos, 
equal ; morphe, shape.] Super- 
ficially alike (biol.\ 

Isomorphism (I'somor'fizm) n. [Gk. 
tsos, equal ; morphe, shape.] Ap- 
parent similarity of individuals of 
different race or species (diol.). 

isomorphous (I'somor'fus) a. Isomor- 

isopedine (isop'edin) n. [Gk. isopedos, 
level.] A layer of compact bony 
material in certain fish scales (zool.). 

isopetalous (I'sopeYalus) a. [Gk. isos, 
equal ; petalon, petal.] Having 
similar petals (dot.). 

isophytoid (I'sofi'toid) a. [Gk. isos, 
equal ; phyton, plant.] An " indi- 
vidual" or part of a compound 
plant not differentiated from the 
rest (dot.). 

isopodous (Isop'odus) a. [Gk. isos t 
equal ; pous, foot.] Having the 
legs alike and equal (zool.). 

Isopogonous (I'sopog'onus) a. [Gk. 
isos, equal ; pogon, beard.] Of 
feathers having the two webs 
equal and similar (zool.). 

isospore (I'sospor 7 ) n. [Gk. isos, equal ; 
sporos, seed.] An agamete pro- 
duced by schizogony ; opp. aniso- 
spore (zool., hot.). 

isosporous (Isos'porus) a. [Gk. isos, 
equal ; sporos, seed.] Having 
spores of one kind only (hot.). 

isostemonous (I'sostgm'onus) a. [Gk. 
isos, equal ; L. stamen, standing.] 
Having stamens equal in number 
to that of sepals and petals (dot.). 

isotely (Tsot'glT) n. [Gk. isos, equal ; 
telos, end.] The close resemblance 
in a homologous character, feature, 
or organ which has undergone 
subsequent modifications on a 
similar line although it may be in 
widely divergent groups (zool., dot.). 

isotomy (Ts6t'6mT) n. [Gk. tsos, 
equal ; temnein, to cut.] Bifurca- 

tion constantly repeated in a 
regular manner, as in crinoid 
brachia (zool.). 

isotonic (I'soton'ik) a. [Gk. isos, 
equal ; tonos, tone.] Of equal 
tension (phys.). 

isotonicity (I'sotonis'iti) n. [Gk. isos, 
equal ; tonos, tone.] Normal ten- 
sion under pressure or stimulus 

isotropous (isot'ropiis) a. [Gk. isos, 
equal ; trepein, to turn.] Not 
influenced in any one direction 
more than another (dot.) ; without 
predetermined axes, as in eggs 

isotropy (isot'ropi) n. [Gk. isos, 
equal ; trepein, to turn.] Absence 
of predetermined axes in eggs. 

isozoic (I'sozo'ik) a. [Gk. isos, equal ; 
zoon, animal.] Inhabited by 
similar forms of animal life (dial ). 

isozooid (I'sozo'oid) n. [Gk. isos, 
equal ; zoon, animal ; eidos, like.] 
A zooid similar to the parent 
stock (zoo!.). 

isthmiate (is'miat) a. [Gk. isthmos, 
neck.] Connected by an isthmus- 
like part. 

isthmus (is'mus) n. [Gk. isthmos, 
neck.] A narrow structure con- 
necting two larger parts, as those 
of aorta, acoustic meatus, limbic 
lobe, thyroid, etc. (anat.). 

iter (ft'Sr) n. [L. iter, way.] A 
passage or canal, as those of the 
middle ear, brain, etc. ; an aque- 
duct (anat.). 

ivory (I'vori) n. [L. edur, ivory, 
through French.] Dentine of teeth, 
usually that of the elephant's tusks 
and similar structures, formed from 
the odontoblasts. 

Jacobson's cartilage, a special carti- 
lage formed in the nose region, 
supporting Jacobson's organ. 

Jacobson's organ, a diverticulum of 
the olfactory organ in many verte- 
brates, often developing into an 
epithelium-lined sac which opens 
into the mouth. 




jaculator (jak'ulator) n. [L. jaculatus, 
thrown.] A placental process, 
usually hook-shaped, of certain 
fruits (hot.). 

jaculatory (jak'ulatorf) a. [L. jacu- 
latorius, throwing.] Darting out; 
capable of being emitted (zoo/.). 

jaculatory duct, a portion of the 
vas deferens in many animals, 
which is capable of being pro- 
truded (zool.}. 

jaculiferous (jak'ulif'erus) a. [L. 
jaculum, a dart ; ferre, to carry.] 
Bearing dart-like spines. 

jaw (jo) n. [Akin to chaw, cheivl\ 
A structure of vertebrates supported 
by bone or cartilage, naked or 
sheathed in horn, or bearing teeth 
or horny plates, forming part of 
the mouth, and helping to open 
or shut it ; in invertebrates, a 
similarly placed structure. 

jaw-bone, the mandible. 

jaw-foot, a maxillipede of Arthro- 
pods (zool.}. 

jecorin (jSk'orin) n. [L.jecur, liver.] 
A lecithin-like phosphorized sub- 
stance present in many of the 
organs of the body in minute 
quantities, and soluble in ether 

jejunum (jejoon'um) n. [L. jejunus, 
empty.] The part of the small 
intestine stretching from the duo- 
denum to the ileum (anat.}. 

jelly of Wharton, the mucoid tissue 
found in connection with the vessels 
of the umbilical cord (anat.}. 

jubate (joob'at) a. [L. jubatus, 
maned.j With mane-like growth 

jugal (joog'al) n. [L. jugum, yoke.] 
The malar bone, between maxilla 
and squamosal. 

jugate (joog'at) a. [L.jugum, yoke.] 
Having pairs of leaflets (bot.} ; 
furnished with a jugum (zool.). 

jugular (joog'ular, jug-) a. [L. jugu- 
lum, a collar-bone.] Pert, neck or 
throat ; appl. ventral fish-fins be- 
neath and in front of pectoral fins 

jugulum (joog'ulum, jug-) n. [L. 
jugulum, collar-bone.] The fore- 
neck region of a bird's breast ; in 
Insects, the jugum of the wing 

jugum (joog'iim) n. [L.jugum, yoke.] 
A pair of opposite leaflets ; a ridge 
on the mericarp of umbelliferous 
plants (dot.} ; a small forewing lobe 
of a very few moths with no fren- 
ulum (zool.} ; the union of the small 
sphenoidal wings in the first year 
after birth (anat.}. 

juice (joos) n. [L.jus, mixture.] The 
fluid contained in animal flesh or 
plant structure (phys.). 

Jurassic (jooras'ik) a. [Jura moun- 
tains.] Occurring in the middle 
Secondary rock-system, the eighth 
of the thirteen systems (pal.}. 


kakogenesis (kak'ojen'gsls) n. [Gk. 
kakos, bad ; genesis, descent.] In- 
ability to hybridize (biol.}. 

kalldium (kalid'ium) n. [Dim. Gk. 
kalia, a hut.] A form of sporocarp 

kalymmocytes (kaltm'osits) n. plu. 
[Gk. kalymma, covering ; kytos, 
cell.] In Ascidians, certain follicle- 
cells which migrate into the egg 
after maturation (zool.}. 

karyaster (karias'ter) n. [Gk. karyon, 
nucleus ; aster, star.] A star-shaped 
group of chromosomes (cyt.}. 

karyenchyma (kar'Igng'kTma) n. [Gk. 
karyon, nucleus ; engchyma, in- 
fusion.] Nuclear sap (cyt.}. 

karyogamy (kar'iog'aml) n. [Gk. 
karyon, nucleus ; games, union.] 
Union and interchange of nuclear 
material (cyt.}. 

karyokinesis (karfokine'sis) n. [Gk. 
karyon, nucleus ; kinein, to change.] 
Indirect cell-division; mitosis (cyt.}. 

karyolymph (kar'iolimf) n. [Gk. 
karyon, nucleus ; L. lympha, water.] 
Nuclear sap (cyt.}. 

karyolysls (kar'iol'lsls) n. [Gk. kar- 
yon, nucleus ; lyein, to loosen.] 
Supposed dissolution of the nucleus 
in mitosis (cyt.}. 

karyomlcrosome (kar'iomi'krosom) 11. 
[Gk. karyon, nucleus ; mikros, small ; 
soma, body.] A nuclear granule 





karyomite (kar'lomlt') n. [Gk. kar- 
yon, nucleus ; mitos, thread.] A 
chromosome (cyt.}. 

karyomitome (karTomitom') n. [Gk. 
karyon, nucleus ; mitoma, network.] 
Nuclear network of fibres (cyt.}. 
karyomitosis (kar'iomito'sis) n. [Gk. 
karyon, nucleus ; mitos, thread.] 
Indirect nuclear division (cyt.}. 
karyon (kar'ion) n. [Gk. karyon, 

nucleus.] The cell-nucleus (cyt.}. 
karyophans (kar'iofanz') n. plu. [Gk. 
karyon, nucleus ; phainein, to 
appear.] Microsomes or nucleus- 
like granules surrounded by an 
ovoid matrix, which form the 
spironeme and axoneme in stalk 
of Infusoria (cyt.}. 

karyoplasm (kar'toplazm) n. [Gk. 
karyon, nucleus ; plasma, something 
moulded.] The nucleoplasm or 
nuclear substance (cyt.}. 
karyorhexis (kar'iorek'sis) n. [Gk. 
karyon, nucleus ; rexis, breaking.] 
Fragmentation of the nucleus (cyt.}. 
karyosome (kar'iosom) n. [Gk. kar- 
yon, nucleus ; soma, body.] One 
of the nucleoli of the "net-knot" 
type ; a chromosome ; a special 
aggregation of chromatin in the 
resting nucleus ; the cell-nucleus 
itself ; cf. plasmosome (cyt.}. 
karyota (kario'ta) n. plu. [Gk. kar- 
yon, nucleus.] Nucleated cells, 
karyotheca (kar'iothe'ka) n. [Gk. 
karyon, nucleus ; theke, covering.] 
The nuclear membrane (cyt.}. 
katabolism (katab'olizm) n. [Gk. 
kata, down ; ballein, to throw.] The 
destructive processes of metabolism 

kataphoric (katafor'ik) a. [Gk. kata, 
down ; pherein, to carry.] Appl. 
passive action, the result of lethargy 

kataplexy (kat'aplek'si) n. [Gk. kata, 
down ; plessein, to strike.] Con- 
dition of an animal feigning death 

katastate (katas'tat) n. [Gk. kata, 
down ; stasis, state.] Any product 
of katabolic activity of protoplasm 

kathodic (kathod'ik) a. [Gk. kathodos, 
descent.] Not arising in conforma- 
tion to the genetic spiral ; appl. 
leaves (bot.}. 

kation (katl'on) ;/. [Gk. kata, down ; 
ienai, to go.] A positively charged 
ion which moves towards the 
kathode or negative pole ; opp. 
anion (phys.}. 

keel (kel) n. [A.S. ceol, ship.] The 
carina or breast-bone of flying birds 
(zool.} ; the boat-shaped structure 
formed by the two anterior petals 
of the Leguminosae (bot.}. 
keraphyllous (keraf'iltis) a. [Gk. 
keras, horn ; phyllon, leaf.] Appl. 
layer of a hoof between the horny 
and sensitive parts. 
keratin (ker'atin) n. [Gk. keras, 
horn.] An insoluble substance 
forming the basis of epidermal 
structures such as horns, nails 

keratinization (kerat'iniza'shun) n. 
[Gk. keras, horn.] State of becom- 
ing horny ; appl. cells of epiderm 
developing in a horny material 

keratogenous (keratqj'e'nus) a. [Gk. 
keras, horn ; gignesthai, to produce.] 
Horn-producing (zool.}. 
keratoid (ker'atoid) a. [Gk. keras, 
horn ; eidos, resemblance.] Horny ; 
resembling horn (zool.}. 
keratose (ker'atos) a. [Gk. keras, 
horn.] Having horny fibres in 
their skeleton, as certain Sponges 

kernel (ker'nel) . [A.S. cyrnel, a 
small grain.] The inner part of a 
seed containing the embryo (bot.}. 
kidney (kld'ni) n. [M.E. kidnere, 
kidney.] A urine-secreting organ 

kinaesthetic (kln'esthet'ik) a. [Gk. 
kinein, to move ; aisthesis, percep- 
tion.] Pert, sense of muscular effort ; 
motorial ; appl. sense, area (phys.}. 
kinesodic (km'esod'ik) a. [Gk. kinesis, 
movement ; odos, way.] Conveying 
motor impulses (phys.}. 
kinetic (klnet'lk) a. [Gk. kinein, to 
move.] Appl. energy employed in 
producing or changing motion 
(phys.} ; appl. division centre in 
cell-division (cyt.}. 

kinetoblast (kine'toblast) n. [Gk. 
kinein, to move ; blastos, bud.] The 
outer ciliated investment of aquatic 
larvae with special locomotor prop- 
erties (zool.}. 




kinetogenesis (kine'toje'n'e'sis) n. 
[Gk. kinein, to move ; gignesthai, 
to produce.] The evolution theory 
that animal structures have been 
produced by animal movements 

kinetonucleus (klne'tonu'kleus) n. 
[Gk. kinein, to move ; L. nucleus, 
kernel.] The secondary nucleus, 
in forms such as Trypanosomes, 
in close connection with the flag- 
ellum and undulating membrane ; 
cf. trophonucleus (cyt.}. 

kinetoplasm (kine'toplazm) n. [Gk. 
kinein, to move ; plasma, some- 
thing formed.] An iron-contain- 
ing nucleo-protein forming a source 
of energy to Nissl granules of 
nerve-cells (phys.}. 

kinoplasm (km oplazm) n. [Gk. 
kinein, to move ; plasma, some- 
thing formed.] The substance of 
which attraction-sphere, astral 
rays, and spindle-fibres consist ; 
archoplasm (cyt.}. 

klasma-plates (klas'ma-plats) n. plu. 
[Gk. klasma, fragment ; L. platus, 
flat.] Small parts of compound 
ambulacral plates separated by 
growth pressure in certain Echi- 
noids (zool.}. 

kleistogamous (kllstog'amus) a. [Gk. 
kleistos, closed ; gamos, marriage.] 
Fertilized in closed flowers (bot.}. 

knee (ne) n. [A.S. cnecnu, knee.] 
The joint between femur and tibia 
(zool.} ; a root-process of certain 
swamp-growing trees (bot.}. 

knot (not) n. [A.S. cnotta, a knot.] 
In wood, the base of a branch sur- 
rounded by new layers of wood 
and hardened by pressure (dot.) ; 
in nuclear-meshwork, the small 
particles of chromatin where the 
meshes cross (cyt.}. 

labellate (labeTat) a. [L. labellum, 

small lip.] Furnished with labella 

or small lips (dot., zool.}. 
labelloid (labeToid) a. [L. labellum, 

small lip ; Gk. eidos, resemblance.] 

Like a labellum. 
labellum (labeTum) n. [L. labelling 

small lip.] The lower petal, 
morphologically posterior, of an 
orchid (bot.} ; a small lobe beneath 
the labrum in certain insects ; one 
of the proboscis lobes in certain 
insects (zool.}. 

labia (la'bia) n. plu. [L. labium, lip.] 
Lip-like structures (anat.}. 

labia cerebri, the margins of the 
hemispheres of the brain overlap- 
ping the corpus callosum (anaf.}. 

labia majora, the outer lips of the 
vulva (anat.}. 

labia minora, the inner vulvular 
lips (anat.}. 

labial (la'blal) a. [L. labium, lip.] 
Pert, or resembling a lip (zool.}. 

labial palp, the lobe-like structure 
near the mouth of a mollusc ; the 
jointed appendage on the labium 
of Insects (zool.}. 

labiate (la'blat) a. [L. labium, lip.] 
Lip-like ; possessing lips or 
thickened margins (zool.} ; having 
the limb of the calyx or corolla so 
divided that the one portion over- 
laps the other (bot.}. 

labiatiflorous (la'biatiflo'rus) a. [L. 
labium, lip ; flos, flower.] Having 
the corolla divided into two lip- 
like portions (bot.}. 

labidophorous (lab'idof'orus) a. [Gk. 
labis, forceps ; pherein, to carry.] 
Possessing pincer-like organs 

labiella (la'bleTa) n. [L. labium, lip.] 
One of the mouth organs of Myria- 
pods (zool.}. 

labiodental (la'biodgn'tal) a. [L. 
labium, lip ; dens, tooth.] Pert. 
lip and teeth ; appl. to an em- 
bryonic lamina (emb.}. 

labium (la'bium) n. sing, of labia ; 
the fused second maxillae of Insects 

labral (la'bral) a. [L. labrum, lip.] 
Pert, a labrum (zool.}. 

labrum (la'brum) n., labra (la'bra) 
plu. [L. labrum, lip.] The anterior 
lip of Insects, Crustaceans, and 
certain other Arthropods ; the outer 
margin of the mouth of a gastropod 
shell (zool.}. 

labyrinth (lab'frinth) n. [L. laby- 

rinthus, labyrinth.] The complex 

internal ear, bony or membranous ; 

the portions of kidney cortex with 





the uriniferous tubules (anat.) ; the 
tracheal tympanum (zool.). 
labyrinthodont (lab'irin'thodont) a. 
[Gk. labyrinthos, labyrinth ; odous, 
a tooth.] Having teeth with great 
complexity of dentine arrangement 
laccate (lak'at)tf. [It. lacca, varnish.] 

Appearing as if varnished (dot.). 
lacerated (Ias'6rat6d) a. [L. lacerare, 
to tear.] Having the margin or 
apex deeply cut into irregular lobes 
(hot., zool.}. 

lacertiform (lasfir'tiform) a. [L. 
lacerta, lizard ; forma, shape.] 
Having the shape of a lizard 

lachrymal, see lacrimal. 
laclnia (lasin'ia) n. [L. lacinia, flap.] 
Segment of an incised leaf (hot.) ; 
internal endopodite of labium of 
Insects (zool.). 

laciniate (lasm'Iat) a. [L. lacinia, 
flap.] Irregularly incised, as 
petals ; fringed (hot.). 
lacinula (lasin'ula) n. [L. lacinia, 
flap.] Small lacinia (hot., zool.} ; 
the inflexed sharp point of the 
petal (tot.). 

lacinulate (lasin'ulat) a. [L. lacinia, 
flap.] Having lacinulae (dot., zool.). 
lacrimal (lak'rimal) a. [L. lacrima, 
tear.] Pert, or situated 'nejjii-^e 
lacrimal organ; appl. bone, duct, 
papillae, sac, etc. (anat.). ' ., 
lacrimonasal (lak'rlmona'zal) a. ' [L. 
lacrima, tear ; nasum, nose.] Pert. 1 
the lacrimal and nasal bones or 
duct (anat.). 

lacrimose (lak'rimos) a. [L. lacrima, 
tear.] Bearing tear-shaped ap- 
pendages, as the gills of certain 
Fungi (bot.). 

lactalbumin (lak'talbu'min) n. [L. 
lac, milk ; albumin, albumin.] An 
albumin found in milk (phys.). 
lactase (lak'tas) n. [L. lac, milk.] 
An enzyme found in the animal 
body forming glucose, etc., from 
lactose (phys.). 

lactation (lakta'shun) n. [L. lac, 
milk.] Secretion of milk in the 
mammary glands (zool.). 
lacteals (lak'tealz) n. plu. [L. lac, 
milk.] Thechyliferous or lymphatic 
vessels of the smallintestine (anat.); 
ducts which carry latex (tot.). 

lactescent (lakteVgnt) a. [L. lac- 
tescere, to turn to milk.] Produc- 
ing milk (zool.) ; yielding latex 

lactic (lak'tik) a. [L. lac, milk.] 
Pert, milk ; appl. bacilli (phys.). 

lactiferous (laktif'erus) a. [L. lac, 
milk ;ferre, to carry.] Forming or 
carrying milk (zool} ; carrying 
latex (tot.). 

lactochrome (lak'tokrom) n. [L. lac, 
milk ; Gk. chroma, colour.] A 
colouring matter of a nitrogenous 
nature supposed to be in milk 

lactoglobulin (lak'toglob'ulin) n. [L. 
lac, milk ; globulus, dim. of globus, 
globe.] The specific proteid of 
milk, insoluble in water (phys.). 

lactoproteid (lak'topro'teid) n. [L. 
lac, milk ; Gk. protos, first ; eidos, 
resemblance.] Any of the milk 
proteids (phys.). 

lacuna (laku'na) n. [L. lacuna, cavity.] 
A space between cells ; a sinus 
(zool.) ; a urethral follicle ; a cavity 
in bone (anat.) ; a small cavity or 
depression on the surface in Lichens 

lacunar (laku'nar) a. [L. lacuna, 
cavity.] Having or resembling 
lacunae (zool., anat.). 

lacunose (laku'nos) a. [L. lacuna, 
cavity.] With numerous cavities 
(zool., bot.). 

lacunosorugose (lak'unosoroo'gos) 
a. [L. lacuna, cavity ; rugosus, 
wrinkled.] Having deep furrows or 
pits, as some seeds and fruits (bot.). 

lacustrine (lakus'trin) a. [L. lacus, 
lake.] Pert, or being in or beside 
lakes (tot., zool.). 

laeotropic (le'otrop'ik) a. [Gk. laios, 
left ; trepein, to turn.] Inclined, 
turned, or coiled to the left (zool.). 

laeotropous (leot'ropus). Laeotropic. 

lagena (lagen'a, laje'na) ;/., lagenae 
(lage'na, lajen'e) plu. [L. lagena, 
flask.] An outgrowth of the sac- 
culus, the terminal portion of the 
cochlea (zool.). 

lageniform (lage'mform, laje'niform) 
a. [L. lagena, flask ; forma, shape.] 
Shaped like a flask (zool.). 

lagopodous (lagop'odus) a. [Gk. 
lagos, hare ; pous, foot.] Possessing 
hairy or feathery feet (zool.). 



Lamarckian (lamark'ian) a. [F. 
Lamarck, biologist.] Of or pert. 
the theories put forward by Lamarck 

Lamarckism (lamark'izm) n. [F. 
Lamarck, biologist.] The evolution 
theory of Lamarck, embodying the 
principle that acquired character- 
istics are transmissible (diol.). 

lambda (lam'da) n. [Gk. A, lambda.] 
The junction of the lambdoid and 
sagittal sutures (anat.). 

lambdoid (lam'doid) a. [Gk. A, 
lambda ; eidos, resemblance.] A- 
shaped ; appl. a cranial suture 

lambdoidal, lambdoid. 

lamella (lamel'a) n. [L. lamella, a 
small plate.] Any thin plate-like 
structure (anat., zool.) ; the gill of 
an Agaric (dot.). 

lamellar (lameTar) a. [L. lamella, a 
small plate.] Composed of, or 
possessing thin plates (zool., dot.). 

lamellate (lamel'at). Lamellar. 

lamellibranchiate (lameTibrang'kiat) 
a. [L. lamella, thin plate ; Gk. 
brangchia, gills.] Having plate- 
like gills on each side ; with bi- 
laterally compressed symmetrical 
body, like a bivalve (zool.). 

lamellicorn (lameTikorn) a. [L. 
lamella, plate ; cornu, horn.] Hav- 
ing antennal joints expanded into 
flattened plates (zojf.). 

lamelliferous (lam'elif'e'rus) a. [L. 
lamella, plate ; ferre, to cawy.j 
Having small plates or scales 

lamelliform (lamel'iform) a. [L. la- 
mella, plate ; forma, shape.] Plate- 
like (zool.). 

lamellirostral (lamgl'iros'tral) a. [L. 
lamella, plate ; rostrum, beak.] 
Having the inner edges of the 
bill bearing lamellar-like ridges 

lamelloss (lameTos, lam'los), lamellar. 

lamina (lam'ina) n. [L. lamina, plate.] 
A thin layer, or scale ; one of the 
thin plate-like expansions of sensi- 
tive tissue which fit into the grooves 
on the inside of the horse-hoof 
(zool.) ; the blade of the leaf (dot.). 

laminar (lam'mar) a. [L. lamina, 
plate.] Consisting of plates or thin 
layers (dot., zool.). 

laminiform (lamin'iform) a. [L. lam- 
ina, plate ; forma, shape.] Laminar. 

laminiplantar (lam'inTplan'tar) a. [L. 
lamina, plate ; planta, sole of foot.] 
Having the scales of the metatarsus 
meeting behind in a smooth ridge 

laminous (lam'inus) a. [L. lamina, 
plate.] ^Laminar. 

lanate (lan'at) a. [L. lana, wool.] 
Woolly (zool.) ; covered with short 
hair-like processes giving a woolly 
appearance to the surface (dot.). 

lance-linear (lans'-lin'ear) a. [L. 
lancea, lance ; linea, line.] Between 
lanceolate and linear in form ; appl. 
leaves (dot.). 

lance-oblong (lans'-ob'long) a. [L. 
lancea, lance ; odlongus, oblong.] 
Oblong with tapering ends ; appl. 
leaves (dot.). 

lanceolate (lan'seolat) a. [L. lanceola, 
little lance.] Broad at base and 
tapering to the point ; lance-shaped 
(dot., zool.). 

lance-oval (lans'-o'val) a. [L. lancea, 
lance ; ovalis, oval.] Something 
between lanceolate and oval (dot.). 

lance-ovate (lans'-o'vat) a. [L. lancea, 
lance ; ovalis, oval.] Something 
between laftceolate and ovate (dot.). 

lancefejaafoisi, speciad'plates support- 
I &iHf&^ e water-vascular vessels of 
\,^TJlastoMs (jppJit). 

Langerhans, see islets of Langer- 
y. V nAnsT 

Vlanguet, languette (lang'gwe't) n. 
[F. langue, tongue.] A process on 
the branchial sac of Ascidians 

laniary (lan'iari) a. [L. laniare, to 
tear in pieces.] Term appl. to 
canine tooth (zool.). 

lantern, see Aristotle's lantern 
. (zool.). 

lanthanin (lan'thanin) n. [Gk. lan- 
thanein, to conceal.] Oxychro- 

lanuginous (lanu'jinus) a. [L. lanugo, 
wool.] Woolly (dot., zool.). 

lanugo (lanu'go) n. [L. lanugo, wool.] 
The downy covering on a foetus, 
shed early in life (anat.). 

lapidicolous (lap'Idik'olus) a. [L. 
lapis, stone ; colere, to cultivate.] 
Appl. animals that live under 
stones (zool.). 




lappaceous (lapa'shus) a. [L. lappa, 
bur.] Prickly (dot.). 

lappet (lap'et) n. [M.E. lappe, a loose 
hanging part.] One of the paired 
lobes extending downwards from 
the distal end of the stomodaeum 
in jelly-fish ; the lobes of a sea- 
anemone gullet ; the wattle of a 
bird (zool.). 

larva (lar'va) n. [L. larva, ghost.] 
An embryo which becomes self- 
sustaining and independent before 
it has assumed the characteristic 
features of its parents (zool.). 

larval (lar'val) a. [L. larva, ghost.] 
Pert, or in the larval stage (zool.). 

larviform (lar'viform) a. [L. larva, 
ghost ; forma, shape.] Shaped like 
a larva (zool.). 

larvigerous (larvlj'erus) a. [L. larva, 
ghost ; gerere, to bear.] Coarctate 

larvlparous (larvip'arus) a. [L. larva, 
ghost ; parere, to produce.] Pro- 
ducing live larvae (zool.). 

larvlvorous (larviv'orus) a. [L. larva, 
ghost ; vorare, to devour.]" Larva- 
eating (sool.). 

larvule (lar'vul) n. [L. larvula, small 
larva.] Young larva (zool.). 

laryngeal (larin'jeal, lar'fnje'al) a. 
[Gk. larynx, upper part of wind- 
pipe.] Pert, or near the larynx ; 
appl. artery, vein, nerve, etc. 

laryngotracheal (laring'gotra'keal, 
larin'jo-) a. [Gk. larynx, windpipe ; 
L. trachea, trachea.] Pert, larynx, 
and trachea ; appl. embryonic tube 

larynx (lar'inks);*., larynges (larin'jez) 
plu. [Gk. larynx, the larynx.] The 
organ of voice in most vertebrates, 
with the exception of birds (zool.). 

lasso-cells, filamented hemispheri- 
cal cells investing the tentacles 
of Ctenophores, which adhere to 
foreign bodies (zool.). 

latebra (lat'ebra) n. [L. latebra, 
hiding-place.] The bulb of the 
flask-shaped mass of white yolk in 
eggs (emb.). 

latebricole (latgb'rikol) a. [L. latebra, 
hiding-place ; colere, to cultivate.] 
Inhabiting holes. 

latent (la'tSnt) a. [L. latere, to lie 
hid.] Lying dormant but capable 

of development under favourable 
circumstances ; appl. buds (hot.) ; 
resting stages (zool.) \ character- 
istics (biol.). 

latent bodies, the resting stage of 
certain Haemoflagellates (zool.). 

lateral (lateral) a. [L. latus, side.] 
Pert, or situated at a side (zool.) ; 
or at a side of an axis (bot.). 

lateral chain theory, see side chain 
theory (phys.). 

lateral line, a longitudinal line at 
each side of the body of Fishes 
marking the position of supposedly 
sensory cells connected together, 
and with the pneumogastric nerve 

lateral mesenteries, the mesenteries 
ofZoantharia, excludingthe directive 
or dorsal and ventral pairs (zool.). 

laterigrade (lat'erigrad) a. [L. latus, 
side ; gradus, step.] Walking side- 
ways, as a crab (zool.). 

laterinerved (lat'erinervd') a. [L. 
latus, side ; nervus, sinew.] With 
lateral veins (bot.). 

latex (la'teks) n. [L. latex, fluid.] A 
milky fluid found in some plants 

laticiferous (lat'isif'erus) a. [L. latex, 
fluid ; ferre, to carry.] Conveying 
latex ; appl. cells, tissue, vessels 

latiplantar (lat'iplan'tar) a. [L. latus, 
side ; filanta, sole of foot.] Having 
the hinder tarsal surface rounded 

latirostral (lat'iros'tral) a. [L. latus, 
broad ; rostrum, beak.] Broad- 
beaked (zool.). 

latiseptate (lat'isep'tat) a. [L. latus, 
broad ; septum, septum.] Having 
a broad septum in the silicula 

Laurer-Stieda canal, a canal leading 
from the junction of the oviduct 
and vitelline duct to open exter- 
nally on the dorsal surface in Tre- 
matodes (zool.). 

laurinoxylon (lor'inok'silon) n. [L. 
laurus, laurel ; Gk. xylon, wood.] 
Any fossil wood. 

law of acceleration, the generaliza- 
tion that organs of greater import- 
ance develop more quickly (emb.). 

lax(laks)a. [L. laxus, loose.] Loose, 
as appl. panicle (bot.). 



layer of Langhans, see cytotropho- 

leader (le'der) n. [A.S. laedan, to 
lead.] Highest shoot or part of 
trunk of a tree (bot.). 

leaf (lef) . [A.S. leaf, leaf.] An 
expanded outgrowth of a stem, 
usually green (bot.}. 

lechriodont (Igk'riodont') a. [Gk. 
lechrios, slantwise ; odous, tooth.] 
With vomerine and pterygoid teeth 
in a row which is nearly if not quite 
transverse (zool.). 

lecithalbumin (Igs'ithalbu'min) n. 
[Gk. lekithos, egg-yolk ; L. albumen, 
white of egg.] A substance, con- 
sisting of albumin and lecithin, said 
to exist in various organs in the 
body (phys.). 

lecithin (leYithin) n. [Gk. lekithos, 
egg-yolk.] A phosphorized fat of 
cell-protoplasm (phys.). 

lecithoblast (leVithoblast) n. [Gk. 
lekithos, egg-yolk ; blastos, bud.] 
In developing eggs, the yolk-con- 
taining blastomeres (smb.). 

lecithocoel (leYithosel) n. [Gk. leki- 
thos, egg-yolk ; koilos, hollow.] The 
segmentation cavity of holoblastic 
eggs (emb.\ 

legume (IggunV, leg'um) n. [L. leg- 
ume n, pulse.] A dehiscent one- 
celled, two-valved carpel, as pod of 
pea or bean (dot.). 

legumin (Iggu'min) n. [L. legumen, 
pulse.] A proteid found in the 
seeds of the Leguminosae (bot.). 

lemniscus (le"mms'kus) n. [Gk. 
lemniskos, fillet.] One of paired 
club-shaped organs at base of 
the acanthocephalan proboscis 
(zool.) ; a fillet of fibres on each side 
of the cerebral peduncles (anat.). 

lens (16nz) n. [L. lens, lentil.] A 
transparent part of the eye which 
focusses rays of light on the 
retina ; the crystalline lens (anat.); 
the modified portion of the cornea 
in front of each element of a 
compound eye (zool.). 

lenticel (16n'tTs61) n. [L. lens, lentil.] 
Ventilating pore in Angiosperm 
stems (bot.). 

lenticular (16ntik'ular) a. [L. len- 
ticula, dim. of lens, lentil.] Shaped 
like a double convex lens (bot., 

lenticular (Igntik'ular) n. The tip of 
the incus articulating with the 
stapes, which is often ossified as 
a separate unit (anat.). 

lenticulate (16ntik'ulat) a. [L. lens, 
lentil.] Meeting in a sharp point ; 
depressed, circular, and frequently 
ribbed (zool.). 

lentiform (len'tiform) a. [L. lens, 
lentil ; forma, shape.] Lenticular. 

lentigerous (le'ntij'e'rus) a. [L. lens, 
lentil ; gerere, to bear.] Furnished 
with a lens (zool.). 

lentiginose (IgntTj'Inos) a. [L. lentigo, 
from lens, lentil.] Freckled ; 
speckled ; bearing numerous small 
dots (zool., bot.). 

lentiginous (IgntijTnus). Lentiginose. 

lepidodendroid (lep'idode'n'droid) a. 
[Gk. lepis, scale ; dendron, tree ; 
eidos, like.] Pert, lepidodendron ; 
having scale-like leaf-scars (pal.). 

lepidophyte (lep'idoflt) n. [Gk. lepis, 
scale ; phyton, plant.] A fossil 
plant of the fern family (pal.). 

lepidopterous (16p'Id6p't6rus) a. [Gk. 
lepis, scale ; pteron, wing.] Pert. 
the Lepidoptera, i.e. having wings 
covered with minute over-lapping 
scales (zool.). 

lepidote (Igp'Idot) a. [Gk. lepis, scale.] 
Covered with minute scales (bot.). 

lepidotic (lep'IdSt'lk) a. [Gk. lepis, 
scale.] Appl. an acid found in 
wings of some Lepidoptera (phys.). 

lepidotrichia (Igp'idotrik'ia) n. plu. 
[Gk. lepis, scale ; thrir, hair.] In 
Teleostomi, bony dermal fin-rays, 
probably modified scales (zool.). 

lepospondylous (Igp'ospon'dllus) a. 
[Gk. lepos, husk ; sphondylvs, 
vertebra.] Having amphicoelous, 
or hour-glass shaped, vertebrae 

leptocephaloid (16p't6k6f'aloid, -s6f-) 
a. [Gk. leptos, slender ; kephale, 
head ; eidos, resemblance.] Re- 
sembling or having the shape of 
a Leptocephalus (zool.). 

leptocercal (Igp'tosgr'kal) a. [Gk. 
leptos, slender; kerkos, tail.] With 
long slender tapering tail, as some 
Fishes (zool.). 

leptodactylous (lep'todak'tilus) a. 
[Gk. leptos, slender; daktylos, 
finger.] Having small or slender 
digits (zool.). 




leptodermatous (Ifip'todeYmatus) a. 
[Gk. leptos, slender ; derma, skin.] 
Thin-skinned; appl, various thecae 

leptodermic (Igp'todgr'mik). Lepto- 

leptodermous (Igp'toder'mus). Lepto- 

leptome (Igp'tom) n. [Gk. leptos, 
slender.] Vascular tissue of 
plant stems ; phloem ; bast (bot.}. 

leptophloem '(ISp'toflo'Sm) n. [Gk. 
leptos, slender ; phloios, smooth 
bark.] Rudimentary bast tissue 

leptophyllous (lep'tofil'us) a. [Gk. 
leptos, slender ; phyllon, leaf.] 
With slender leaves "(bot.}. 

leptosporangiate (Igp'tosporan'jiat) a. 
[Gk. leptos, slender ; sporos, seed ; 
anggeion, vessel.] With sporo- 
genous tissue developing from 
outer cell of periclinal division ; 
opp. eusporangiate (bot.}. 

leptostroterate (lep'tostrot'grat) a. 
[Gk. leptos, slender ; strotos, 
covered.] With ambulacra! plates 
narrow and crowded together, as 
in certain Stelleroidea (zool.}. 

leptoxylem (lep'tozl'lgm) n. [Gk. 
leptos, slender ; xylon, wood.] 
Rudimentary wood tissue (bot.}. 

leptus (Igp'tus) n. [Gk. leptos, small.] 
The six-legged larva of mites 

lethal (le'thal) a. [L. letum, death.] 
Of a parasite, fatal or deadly in 
relation to a particular host (zool.}. 

leuceine (lu'sgin, lu'seen, loo-) n. 
[Gk. leukos, white.] An amino- 
acid formed during the decomposi- 
tion of proteids (phys.}. 

leucine (lu'sen, lu'sln, loo-) n. [Gk. 
leukos, white.] A white nitro- 
genous substance found as a 
constituent of various tissues and 
organs (phys.}. 

leucite (lu'sit, loo-) n. [Gk. leukos, 
white.] A colourless plastid (bot.}. 

leucoblast (lu'koblast, loo-) n. [Gk. 
leukos, white ; blastos, bud.] A 
colourless blood-corpuscle in de- 
velopment (emb.}. 

leucocarpous (lu'kokar'pus, loo-) a. 
[Gk. leukos, white ; karoos, fruit.] 
With the fruit white (bot.}. 

leucocyan (lu'kosfan, loo-) n. [Gk. 

leukos, white ; kyanos, dark blue.] 
A pigment found in certain Algae 

leucocyte (lu'koslt, loo-) n. [Gk. 
leukos, white ; kytos, hollow.] An 
amoebocyte ; a colourless blood- 
corpuscle (anat.}. 

leucocy togenesis (lu'kosi'toj en'esls, 
loo-) n. [Gk. leukos, white ; kytos, 
hollow ; gignesthai, to produce.] 
Leucocyte formation (phys.}. 

leucoplastids (lu'koplas'tidz, loo-) n. 
plu. [Gk. leukos, white ; plastos, 
formed.] Colourless plastids from 
which amylo-, chloro-, and chromo- 
plastids arise (bot.}. 

leucoplasts (lu'koplasts, loo-) n. phi. 
[Gk. leukos, white; plastos, formed.] 
Colourless granules of plant cyto- 
plasm which may develop into 
chromatophores or amyloplasts 

levator (16va/tor) n. [L. levare, to 
raise.] A name given to muscles 
serving to raise an organ or part 

Leydig's duct, the Wolffian duct 

Leydig's organs, minute organs on 
the antennae of Arthropods, sup- 
posed to be organs of smell (zool.}. 

liana (lian'a) n. [L. ligare, to bind.] 
Any luxuriant woody climber of 
tropical or semi-tropical forests 

liber (ll'ber) n. [L. liber, inner bark.] 
Bast (bot.}. 

lichenism (ll'kgnizm) n. [Gk. leichen, 
liverwort.] Symbiotic relationship 
between Fungi and Algae (bot.}. 

lichenoid (H'kgnoid) a. [Gk. leichen, 
liverwort ; eidos, resemblance.] 
Resembling a Lichen (bot.}. 

lichenology (Il'ke"n61'6ji) n. [Gk. 
leichen, liverwort; logos, discourse.] 
The study of Lichens (bot.}. 

Lieberktihn's crypts, tubular glands 
of the intestines (anat.}. 

lien (ll'6n, le'6n) n. [L. lien, spleen.] 

lienal (ll'enal) a. [L. lien, spleen.] 
Pert, spleen ; appl. artery, vein, 
nerve plexus (anat.}. 

lienculus (lign'kulus) n. [L. lien, 
spleen.] An accessory spleen 

lienogastric (lle'nogas'trlk, lea'no-) a. 




[L. /ten, spleen ; gaster, stomach.] 
Pert, spleen and stomach ; appl. 
artery supplying spleen and parts 
of stomach and pancreas (anat.). 

life-cycle the various phases through 
which an individual species passes 
to maturity (biol.). 

ligament (lig'amgnt) . [L. liga- 
mentum, bandage.] A strong 
fibrous band of tissue connecting 
two or more moveable bones (anat.). 

ligneous (ITg'neus) a. [L. lignum, 
wood.] Woody ; of the nature of 
wood (tot.). 

lignescent (lignSs'e'nt) a. [L. lignes- 
cere, to become woody.] Develop- 
ing the characters of woody tissue 

ligmicolous (iTgnik'olus)tf. \L.lignum, 
wood ; colere, to cultivate.] Grow- 
ing on wood (tot.). 

ligniflcation (Hg'nifika'shun) n. [L. 
lignum, wood ; facere, to form.] 
Wood-formation, the thickening of 
plant cell-walls by the deposition 
of lignin (tot.). 

lignin (Ilg'nen, lig'ntn) n. [L. lignum, 
wood.] The substance which, modi- 
fied by cellulose, causes the thicken- 
ing of plant cell-walls, and so forms 
wood (tot.). 

lignivorous (ligmv'orus) a. [L. lig- 
num, wood ; vorare, to devour.] 
Eating wood; appl. various Insects 

lignocellulose (Ifg'noseTulos) n. [L. 
lignum, wood ; cellula, little cell.] 
The essential constituent of woody 
tissue, lignin and cellulose com- 
bined (tot.). 

lignose (lig'nos) n. [L. lignum, wood.] 
A variety of cellulose (tot.). 

ligula (lig'ula) n. [L. ligula, little 
tongue.] A band of white matter 
in the wall of the fourth ventricle 
(anat.) ; a process on the wall of 
the mouth of Insects (zool.). 

ligulate (Itg'ulat) a. [L. ligula, little 
tongue.] Having or pert, ligules ; 
strap-shaped, as the ray flowers of 
Compositae (tot.). 

llgule (Hg'ul) n. [L. ligula, little 
tongue.] A membranous append- 
age at the junction of blade and 
petiole ; a supra-sporangial scale in 
Selaginella (tot.) ; one of the lobes 
qf the annelidan parapodium (zool.). 

liguliflorous (ITg'ulIflo'rus) a. [L. 
ligula, little tongue ; flos, flower.] 
Having ligulate flowers only (dot.). 
limacel (Hm'asgl) n. [L. Umax, slug.] 
The concealed vestigial shell of 
slugs (zool.). 

limaciform (limas'lform) a. [L. 
Umax, slug ; forma, shape.] Like 
a slug (zool.). 

limacine (Itm'asin) a. [L. Umax, 
slug.] Pert, or resembling a slug 
limb (Hm) n. [A.S. Urn, limb.] 

Branch ; arm ; leg ; wing, 
limbic (llm'blk)a. [L. limbus, border.] 
Bordering ; appl. a cerebral lobe 

limbous (lim'bus) a. [L. limbus, 
border.] Appl. overlapping su- 
tures (anat.). 

limbus (lim'bus) n. [L. limbus, 
border.] Any border if distinctly 
marked off by colour or structure 
(zool., hot.). 

limicolous (limlk'olus) a. [L. limus, 
mud; colere, to dwell.] Living in 
mud (zool., tot.). 

limivorous (lirmVorus) a. [L. limus, 
mud ; vorare, to devour.] Mud-eat- 
ing ; appl. certain aquatic animals 
which swallow mud (zool.). 
limnetic (llmngt'lk) a. [Gk. limne, 
marsh.] Living in marshes ; pert. 
organisms of marshy habitat (tot., 

limnophilous (limnofilus) a. [Gk. 
limne, marsh ; philein, to love.] 
Living in fresh-water marshes ; 
appl. snail, etc. (zool.). 
limnoplankton (Iim'noplang'kt6n) n. 
[Gk. limne, marsh ; plangktos, 
wandering.] The floating animal 
and plant life in fresh-water ponds 
and marshes ; cf. hallplankton. 
line (lin) n. [A.S. line, cable.] A 
line ; anatomical term, such as 
nuchal, temporal line (anat.). 
linea (Hn'ea) n. [L. linea, line.] A 

line, which see. 
linear (lln'ear) a. [L. linea, line.] 

linear-ensate (lln'ear-gn'sat) a. [L. 
linea, line ; ensis, sword.] Between 
linear and ensiform in shape ; appl 
leaves (tot.). 

linear - lanceolate (lln'ear-lan'seolat) 
a. [L. lineO) line ; lanceola^ small 




lance.] Between linear and lanceo- 
late in shape ; appl. leaves (bot.). 

linear-oblong (Im'ear-ob'long) a. [L. 
tinea, line ; oblongus, long across.] 
Between linear and oblong in 
shape ; appl. leaves (hot.). 

linellae (linel'e) n. plu. [L. linella, 
fine thread.] A system of filaments 
in certain Sarcodina holding to- 
gether the xenophya (zool.}. 

lineolate (lin'eolat) a. [L. linea, line.] 
Marked by fine lines or striae 
(bot., zool.). 

lingua (ling'gwa) n. [L. lingua, 
tongue.] The floor of the mouth in 
mites ; the hypopharynx of insects ; 
a tongue or tongue-like structure 

lingual (ling'gwal) a. [L. lingua, 
tongue.] Pert, tongue ; appl. radula 
of Molluscs (zool.) ; appl. artery, 
gyrus, nerve, vein (anat.). 

lingula (Img'gula) n. [L. lingula, 
little tongue.] A small tongue-like 
process of bone or other tissue, as 
of cerebellum or sphenoid (anat.}. 

linin (ffnln) n. [L. tinum, flax.] 
The substance of the achromatinic 
reticulum of a cell-nucleus (cyt.). 

Linnaean (Hne'an) a. [L. Linnaeus, 
Swedish naturalist.] Pert, or 
designating the system of classi- 
fication established by Linnaeus 

lip (lip) n. [A.S. lippa, lip.] One of 
the fleshy folds round the mouth ; 
a lip-like structure, such as labia, 
labella, etc. (zool., anat.). 

lip cell, a sporangium cell at the 
point of dehiscence (bot.). 

lipase (lip'as) n. [Gk. lipos, fat.] An 
enzyme, lipolytic in action, found in 
blood and in various organs, and 
also in various seeds (phys.). 

lipochrome (lip'okrom) n. [Gk. lipos, 
fat ; chroma, colour.] A pigment 
found in some Polychaetes (zool.), 
and in some plants (bot.). 

lipogastry (lip'ogas'tri) . [Gk. 
leipesthai, to be lacking ; gaster, 
belly.] Temporary obliteration of 
the gastral cavity, as in some 
Sponges (zool.). 

lipogenous (lipoj'6nus) a. [Gk. lipos, 
fat ; gignesthai, to produce.] Fat- 
producing (bot., zool.). 

lipoid (iTp'oid) a. [Gk. lipos, fat j 

eidos, resemblance.] Any fatty sub- 
stance, such as lecithin, cholesterin, 
found in cells (phys.). 

lipolytic (Hp'olTt'ik) a. [Gk. lipos, 
fat ; lyein, to reduce.] Capable of 
dissolving fat ; fat-reducing (phys}. 

lipomerism (Ifpom'e'rlzm) n. [Gk. 
leipesthai, to be lacking ; meros, 
part.] Suppression of segmenta- 
tion, or coalescence of segments, as 
in Crustaceans (zool.). 

lipostomy (ITpos'tom!) n. [Gk. leipes- 
thai, to be lacking ; stoma, mouth.] 
Temporary obliteration of the 
mouth or osculum (zool.). 

lipoxenous (lipok'sgnus) a. [Gk. 
leipesthai, to be lacking ; xenos, 
host.] Leaving the host before 
completion of development, as in 
case of certain parasites (bot.). 

lipped (Hpt) a. [A.S. lippa, lip.] 
Labiate (bot.). 

lirella (lireTa) n. [L. lira, furrow.] 
A linear apothecium of Lichens 

lissencephalous (lis'gnkeTalus, -sgf-) 
a. [Gk. lissos, smooth ; engkephalon, 
brain.] Having few or no con- 
volutions on the brain (zool.). 

lissoflagellate (lis'oflaj'glat) a. [Gk. 
lissos, smooth ; L. ftagellum, whip.] 
Having no collar surrounding the 
base of the flagellum (zool.). 

lithite (iTth'lt) n. [Gk. lithos, stone.] 
A calcareous secretion found in 
connection with the ear, or with 
otocysts, lithocysts, and tentaculo- 
cysts, the supposed auditory organs 
of many invertebrates (anat., zool.). 

lithocysts (lith'osists) n. plu. [Gk. 
lithos, stone ; kystis, bladder.] 
Minute sacs or grooves, containing 
lithites, found in various inverte- 
brates ; the marginal sense-organs 
of certain Coelenterates (zool.). 

lithodesma (lith'odeVma) n. [Gk. 
lithos, stone ; desma, bond.] A 
small plate, shelly in nature, found 
in certain bivalves (zool.). 

lithodomous (lithod'timus) a. [Gk. 
lithos, stone ; demein, to build.] 
Living in rocks (zool.). 

lithogenous (Hthqj'e'nus) a. [Gk. 
lithos, stone ; gignesthai, to pro- 
duce.] Rock-forming, or rock- 
building, as certain corals (zool.). 

lithophagous (lithof'agus) a, [Gk. 




lithos, stone ; phagein, to eat.] 
Stone-eating, as Birds ; rock- 
burrowing, as Molluscs (zoo/.). 

lithophilous (lithofilus) a. [Gk. 
lithos, stone ; philein, to love.] 
Growing on stones or rocks (bot.). 

lithophyll (lith'ofil) n. [Gk. lithos, 
stone ; fihyllon, leaf.] A fossil leaf, 
or leaf-impression (J>al.). 

lithophyte (lith'oflt) n. [Gk. lithos, 
stone ; phyton, plant.] A plant 
growing on rocks or in rocky 
places (bot.). 

lithotomous (lithot'omiis) a. [Gk. 
lithos, stone ; temnein,\.o cut.] Stone- 
boring, as certain Molluscs (zoo/.). 

littoral (Ht'oral) a. [L. littus, sea- 
shore.] Growing or living at or 
near the sea-shore (biol.). 

liver (liv'er). [A.S. lifer, liver.] A bile- 
secreting gland of vertebrates (zoo/.). 

liver-pancreas, an organ in Molluscs 
and Crustaceans combining the func- 
tionsof the liver and pancreas (zoo/.). 

lobate (lo'bat) a. [Gk. lobos, lobe.] 
Divided into lobes. 

lobe (lob) n. [Gk. lobos, lobe.] A 
flap-like structure on the toes of 
certain birds (zoo/.) ; any rounded 
projection of an organ. 

lobed (lobd) a. [Gk. lobos, lobe.] 
Having the margin cut up into 
rounded divisions by incisions 
which reach less than half-way to 
the mid-rib (bot.). 

lobopodia (lo'bdpo'dia) n. phi. [Gk. 
lobos, lobe ; pous, foot.] Blunt 
pseudopodia of Protozoa (zoo/.). 

lobose (16'bos) a. [Gk. lobos, lobe.] 
Having lobes, or divided up into 
lobes (hot., zoo/.). 

lobular (16b'ular) a. [Gk. lobos, lobe.] 
Like or pert, small lobes (anat.). 

lobulate (ISb'ulat) a. [Gk. lobos, 
lobe.] Divided into small lobes. 

lobule (lob'ul) n. [Gk. lobos, lobe.] 
A small lobe (anat.). 

lobulus (lob'iilus). Lobule. 

lobus (lo'bus). Lobe. 

localization (lo'kaliza'shun) n. L. 
locus, place.] The state of being 
localized (phys.). 

localization of function, reference 
to different parts of the brain as 
communicating centres of the 
various senses (phys.). 

localization of sensation, identifica- 

tion on surface of body of exact 
spot affected (phys.). 

locellus (loseTus) n. [L. locellus, 
from locus, place.] A small com- 
partment of an ovary (bot.). 

locomotor rods, hooked or knobbed 
rods for crawling, on the ventral sur- 
face of certain round- worms (zoo/.). 

locular (lok'ular) a. [L. loculus, from 
locus, place.] Containing, or com- 
posed of loculi (bot., zoo/.). 

loculate (lok'ulat). Locular. 

loculicidal (lok'ulfsl'dal) a. [L. locus, 
place ; caedere, to cut.] Dehiscent 
dorsally down the middle of the 
carpels (dot.). 

loculus (lok'ulus) ., loculi (ISk'ulI, 
lok'ule), plu. [L. loculus, from locus, 
place.] A small chamber or cavity ; 
the cavities between the septa in 
certain Coelenterates ; a chamber 
of a foraminiferal shell (zoo/.) ; one 
of the cavities of an ovary (bot.). 

lodicule (16d'Ikul) n. [L. lodicula, 
coverlet.] A scale at the base of 
the ovary in grasses supposed to 
represent a perianth (bot.). 

loma (lo'ma) n. [Gk. loma, fringe.] 
A thin membranous flap forming 
a fringe round an opening (zoo/.). 

lomastome (lo'mastom') n. [Gk. loma, 
fringe ; stoma, mouth.] Having 
the margin of the lip recurved or 
reflected (zoo/.). 

loment (16'mSnt) n. [L. lomentum, 
mixture of bean and rice meal.] 
A legume or pod constricted be- 
tween the seeds (bot.). 

lomentaceous (I6'm6nta'shus) a. [L. 
lomentum, bean meal.] Pert, or 
resembling a loment, or having 
loments (bot.}. 

lomentum (lomeVtum). Loment. 

longicorn (lon'jikorn) a. [L. longifs, 
long; cornu, horn.] Having long an- 
tennae ; appl. certain beetles (zoo/.). 

longipennate (ISn'jipe'n'at) a. [L. 
longus, long \penna, wing.] Having 
long wings, or with long feathers 

longlrostral (Ifin'jlros'tral) a. [L. 
longus, long ; rostrum, beak.] 
With a long beak (zoo/.). 

longitudinal (lon'jltu'dlnal) a. [L. 
longus, long.] Running lengthwise 
or along the line of axis ; appl. 
muscle, nerve, etc. (anat.). 




lophiostomate (Io'ff6st5'mat) a. [Gk. 
lophion, small crest ; stoma, mouth.] 
With crested conceptacle-opening 

lophobranchiate (lo'fobrang'kiat) a. 
[Gk. lophos, crest ; brangchia, gills.] 
With tufted gills (zool.). 

lophocalthrops (lo'fokal'throps) n. 
[Gk. lophos, crest ; A.S. coltraeppe, 
a kind of thistle.] A sponge spic- 
ule with all the rays crested or 
branched (zool.). 

lophocercal (lo'foseVkal) a. [Gk. 
lophos, crest ; kerkos, tail.] Having 
a rayless caudal fin like a ridge 
round the end of the vertebral 
column (zool.}. 

lophodont (lo'fodont) a. [Gk. lophos, 
crest ; odous, tooth.] Having trans- 
verse ridges on the cheek-teeth 
grinding surface (zool.). 

lophophore (lo'fofor) n. [Gk. lophos, 
crest ; pherein, to carry.] An oval 
tentacle-supporting organ in Poly- 
zoa and Brachiopods (zool.). 

lophoselenodont (lo'fosfile'nodont) a. 
[Gk. lophos, crest ; selene, moon ; 
odous, tooth.] Having the cheek 
teeth ridged with crescentic cuspid 
ridges on the grinding surface (zool.). 

lophosteon (lo'fos'teon) n. [Gk. lophos, 
ridge ; osteon, bone.] The keel- 
ridge of a sternum (zool.). 

lophotriaene (lo'fotri'en) n. [Gk. 
lophos, ridge ; triaina, trident.] 

lophotrichous (lofoYrikus) a. [Gk. 
lophos, ridge ; thrix, hair.] Having 
long whip-like flagella (hot., zool.). 

lophs (lofs) n. flu. [Gk. lophos, ridge.] 
Crests which may connect the 
cones in teeth and so form ridges 

loral (lo'ral) a. [L. lorum, thong.] 
Pert, or situated at the lore (zool.). 

lorate (lo'rat) a. [L. lorum, thong.] 
Strap-shaped (tot.). 

lore (lor) n. [L. lorum, thong.] The 
space between bill and eyes in 
birds (zool.). 

lorica (loYlka) n. [L. lorica, corselet.] 
A protective external case found in 
Rotifers and Infusorians (zool.). 

loricate (lor'ikat) a. [L. lorica, corse- 
let.] Covered with protective shell 
or scales (zool.). 

lorication moment, the occasion of 

the deposition of silica for an 
entire skeleton at one time (zool.). 

lorum (lo'rum) n. [L. lorum, thong.] 
The piece of the under jaw on which 
the submentum lies in certain 
Insects (zool.). 

loxodont (lok'sodont) a. [Gk. loxos, 
oblique ; odous, tooth.] Having 
molar teeth with shallow grooves 
between the ridges (zool.). 

luciferase (loostf'e'ras) n. [L. lux, 
light \ferre, to carry.] An oxidizing 
enzyme which acts on luciferine, 
causing luminosity in certain ani- 
mals (phys.). 

luciferine (loosif'grin) n. [L. lux, 
light ; ferre, to carry.] The sub- 
stance oxidized by luciferase, caus- 
ing luminosity ; it appears to have 
some of the properties of proteins 

lumbar (lum'bar) a. [L. htmbus, 
loin.] Pert, or near the region of 
the loins ; appl. artery, vein, ver- 
tebra, plexus, gland (anat.). 

lumbocostal (lum'bokos'tal) a. [L. 
lumbus, loin ; costa, rib.] Pert. 
loins and ribs ; appl. arch (anat.). 

lumbosacral (lum'bosa'kral) a. [L. 
lumbus, loin ; sacrum, sacred.] 
Pert, loins and sacrum ; appl. 
nerve-plexus, trunk (anat.). 

lumbriciform (Iumbrls'if6rm) a. [L. 
lumbricus, earth-worm ; forma, 
shape.] Like a worm (zool.). 

lumbricoid (lum'brlkoid). Lumbrici- 

lumen (lii'mSn, loo-) n. [L. lumen, 
light.] The cavity of a tubular 
part or organ (anat.). 

luminous organs, specialized organs 
for the production of light, found 
in fireflies, deep-sea fishes, glow- 
worms, etc. (zool.). 

lunar (lu'nar, loo-) a. [L. luna, 
moon.] Appl. carpal bone ; also 
called semilunar and intermedium ; 
lunate (zool.). 

lunare (lunar'e, loona'ra) n. [L. luna, 
moon.] The lunar bone (anat.). 

lunate (lu'nat, loo-) a. [L. luna, 
moon.] Somewhat crescent-shaped 

lung (lung) n. [A.S. lunge, lung.] 
The paired or single respiratory 
organ of air-breathing higher 
a.nimal forms (zool.). 




lung-book, the respiratory organ of 
Scorpionids, formed like a purse 
with numerous compartments 

lunular (lu'nular, loo-) a. [L. lunula, 
small moon.] Marked with cres- 
cent-shaped marking (zool.}. 

lunulate (lu'nulat, loo-). Lunular. 

lunule (lu'nul, loo-) n. [L. lunula, 
small moon.] A crescent-shaped 
marking (zool.}. 

lunulet (lu'nulSt, loo-) n. [L. lunula, 
small moon.] A small lunule 

lupulin (lu'pultn, loo'pulln) n. [L. 
lupus, a hop.] The resinous gland- 
ular scales of hops (hot.} ; an 
organic compound, bitter and acrid, 
obtained from these (phys.}. 

lutein (lu'tein, loo-) n. [L. luteus, 
orange-yellow.] The yellow pig- 
ment of egg-yolk (phys.}. 

lychnidiate (liknld'iat) a. [Gk. lych- 
nis, phosphorescent gem.] Lumin- 
ous (zool.}. 

lymph (limf) n. [L. lympha, water.] 
An alkaline colourless fluid con- 
tained in the lymphatic vessels 
(anaf., phys.}. 

lymph heart, a contractile expan- 
sion of a lymph vessel where it 
opens into a vein, found in many 
of the vertebrates (zool.}. 

lymphatic (Hmfat'ik) a. [L. lympha, 
water.] Pert, or conveying lymph 

lymphocyte (lim'foslt) n. [L. fympha, 
water ; Gk. kytos, hollow.] A 
colourless corpuscle found in blood 
and lymph (phys.}. 

lymphogenlc (llm'fojen'ik) a. [L. 
lympha, water ; Gk. gignesthai, to 
produce.] Produced in the lymph- 
glands (phys.}. 

lymphogenous (limfoj'e'nus) a. [L. 
lympha, water ; Gk. gignesthai, to 
produce.] Lymph-forming (phys., 

lymphold (lim'foid) a. [L. lympha, 
water ; Gk. eidos, resemblance.] 
Appl. retiform tissue with meshes 
largely occupied by lymph cor- 
puscles ; adenoid (phys.}. 

lyophll (li'ofil) a. [Gk. lyein, to loose ; 
philos, loving.] Appl. solutions 
which, after evaporation to dry- 
ness, go readily into solution again 

on the addition of a fluid ; cf. 
lyophobe (phys.}. 

lyophobe (Ifofob) a. [Gk. lyein, to 
loose ; phobos, fear.] Appl. solu- 
tions which, after evaporation to 
dryness, remain as a solid ; cf. 
lyophll (phys.}. 

lyotropic (llotrop'ik) a. [Gk. lyein, to 
loose ; trope, a turning.] Appl. 
solutions which are dependent on 
changes in the solvent itself 

lyra (li'ra) n. [Gk. lyra, lyre.] Tri- 
angular part of the corpus callosum, 
marked with lines as a lyre (anat.}. 
lyrate (ffrat) a. [Gk. lyra, lyre.] 
Lyre-shaped ; appl. certain leaves 

lysactinic (Hsaktln'Ik) a. [Gk. lysis, 
a loosing ; aktis, ray.] Of Stel- 
leroidea, having the podia limited 
to the lower half of the body instead 
of continued to the apical plates ; 
cf. desmactlnic (zool.}. 
lyslgenous (lisij'gnus) a. [Gk. lysis, 
loosing ; gignesthai, to produce.] 
Appl. formation of tissue cavities 
caused by the degeneration and 
breaking down of cell-walls in the 
centre of the mass (bot.}. 
lysln (li'sin) n. [Gk. lysis, loosing.] 
Any substance capable of destroy- 
ing bacteria (phys.}. 
lysogenesls (Irsojen'ests) n. [Gk. 
lysis, loosing ; gignesthai, to pro- 
duce.] The action of lysins (phys.}. 
lysogenous (llsoj'e'nus). Lysigenous. 
lyssa (lis'a) n. [Gk. lyssa, madness.] 
A vermiform structure of cartilage, 
muscle, and connective tissue, 
under the tongue of Mammals 

lytta (llt'a) n. [Gk. lytta, madness.] 
A cartilaginous or fibrous rod lying 
in the tongue of Carnivores (zool.}. 


macerate (m&s'erat) v. [L. macerare, 
to soften.] To wear away or to 
isolate the parts of a tissue or 
organ (zool.} ; to soften and wear 
away by digestion or other means 

machopolyp (mak'6p611p) n. [Gk, 




mache, fight ; polys, many ; pous, 
foot.] A nematophore of certain 
Hydromedusae provided with 
cnidoblasts or adhesive globules 

inacrandrous (makran'drus) a. [Gk. 
makros, large , aner, man.] Having 
large male plants or elements 

macrobiotic (mak'robiot'ik) a. [Gk. 
makros, large ; bios, life.] Long- 
lived ; life-prolonging (btol.). 

macroblast (mak'rdblast) n. [Gk. 
makros, large ; blastos, bud.] A 
large cell or corpuscle (zool.). 

macrocarpous (mak'rokar'pus) a. [Gk. 
makros, large ; karpos, fruit.] Pro- 
ducing large fruit (bot.). 

macrocephalous (mak'rokef'alus, -s6f-) 
a. [Gk. makros, large ; kephale, 
head.] Having the cotyledons 
thickened (bot.) ; big-headed (anat.). 

macrocnemic (mak'rokne'mik) . [Gk. 
makros, large ; kneme, tibia.] Appl. 
Zoanthidae having the sixth proto- 
cneme or primary pair of mesen- 
teries perfect (zool.). 

macroconidium (mak'rokonid'ium) n. 
[Gk. makros, large ; konis, dust.] 
A large asexual spore or conidium 

macroconjugant (mak'rokon'joogant) 
n. [Gk. makros, large ; L. conju- 
gare, to unite.] The large indi- 
vidual of a conjugating pair, as the 
ordinary sedentary Vorticellan to 
which the motile microconjugant 
or individual attaches itself (zool.). 

macrocyst (mak'rosist) n. [Gk. makros, 
large ; kystis, bladder.] A large 
reproductive cell of certain Fungi ; 
a large cyst or case, as for spores 

macrocytase (mak'rosi'tas) n. [Gk. 
makros, large ; kytos, hollow.] The 
enzyme of macrophages or endo- 
thelial cells (phys.). 

macrodactylous (mak'rodak'tilus) a. 
[Gk. makros, large ; daktylos, finger.] 
With long digits (zool.}. 

macrodont (mak'rodont) a. [Gk. 
makros, large ; odous, tooth.] With 
large teeth (anat.). 

macrogamete (mak'rogamet') n. [Gk. 
makros, large; gametes, spouse.] 
The larger of two conjugants, 
usually considered as equivalent 

to the ovum or female conjugant 

macrogametocyte (mak'rogame'toslt) 
n. [Gk. makros, large ; gametes, 
spouse ; kytos, hollow.] The mother- 
cell of a macrogamete, considered 
female ; term used mainly in con- 
nection with Protista (biol.). 

macrogamy (makrog'ami) n. [Gk. 
makros, large ; gamos, marriage.] 
Syngamy between full-grown in- 
dividuals of a species, as in Acti- 
nophrys (zool.). 

macroglossate (mak'roglos'at) a. [Gk. 
makros, large ; glossa, tongue.] 
Furnished with a large tongue. 

macrognathic (mak'rognath'ik) a. 
[Gk. makros, large ;' gnathos, jaw.] 
Having specially developed jaws 

macrogonidium (mak'rogonid'itim) n. 
[Gk. makros, large ; gone, genera- 
tion.] A large gonidium (bot.). 

macromere (mak'romer) n. [Gk. 
makros, large ; meros, part.] In 
the cleavage of telolecithal eggs, 
one of the larger cells of the lower 
hemisphere (emb.). 

macromerozoite (mak'romer'dzo'it) n. 
[Gk. makros, large ; meros, part ; 
zoon, animal.] One of the many 
divisions produced by the macro- 
schizont stage of a Sporozoan 

macromesentery (mak'romes'enteri) 
n. [Gk. makros, large ; mesas, 
middle ; enteron, gut.] One of the 
larger complete mesenteries of an 
Anthozoan (sool.). 

macromyelon (mak'roml'elon) n. [Gk. 
makros, large ; myelos, marrow.] 
The medulla oblongata (anat.). 

macront (mak'ront) n. [Gk. makros, 
large ; ons, being.] The larger 
of two sets of cells formed after 
schizogony in Neosporidia, the 
macront giving rise to macro- 
gametes (zool.). 

macronucleus (mak'ronu'kleus) n. 
[Gk. makros, large ; L. nucleus, 
kernel.] The larger of two nuclei 
in a cell, usually supposed to be 
of a vegetative or somatic nature 

macrophage (mak'rofaj) n. [Gk. 
makros, large ; phagein, to eat.] 
A large phagocyte or endothelial 




cell possessing the enzyme macro- 
cytase (phys.). 

macrophyllous (mak'rofil'us) a. [Gk. 
makros, large ; phyllon, leaf.] Hav- 
ing elongated leaves or leaflets 

macropodous (makrop'ddus) a. [Gk. 
makros, large \pous, foot.] Having 
a long stalk, as a leaf or leaflet ; 
having the hypocotyl large in pro- 
portion to the rest of the embryo 

macropterous (makrop'te'rus) a. [Gk. 
makros, large \pteron, wing.] With 
unusually large fins or wings 

macroschizogony (mak'roshizog'oni) 
. [Gk. makros, large ; schizein, 
to cleave ; gone, generation.] 
Method of multiplication of the 
macroschizonts (zool.). 

macroschizont (mak'roshiz'ont) n. 
[Gk. makros, large ; schizein, to 
cleave.] A stage in the life-cycle 
of certain Haemosporidia de- 
veloped from a sporozoite, and 
giving rise to a number of macro- 
merozoites (zool.). 

macroscopic (mak'roskop'ik) a. [Gk. 
makros, large ; skopein, to view.] 
Visible to the naked eye. 

macrosepalous (mak'rosep'alus) a. 
[Gk. makros, large ; sepalon, sepal.] 
With specially large sepals (dot.). 

macroseptum (mak'rose'p'tum) n. 
[Gk. macros, large ; L. septum, 
division.] A primary or perfect 
septum of the Anthozoa (zool.). 

macrosmatic (mak'rosmat'ik) a. [Gk. 
makros, large ; osme, smell.] With 
well - developed sense of smell 

macrosomatous (mak'rosom'atus) a. 
[Gk. ma&ros, large ; soma, body.] 
Possessing an abnormally large 

jlofor) n. [Gk. makros, large ; 
sporos, seed ; anggeion, vessel ; 
pherein, to bear.] A structure 
bearing a macrosporangium (hot.}. 

macrosporangium (mak'rosporan'- 
jium) n. [Gk. makros, large ; sporos, 
seed ; anggeion, vessel.] A spor- 
angium developing macrospores or 
megaspores (bot.). 

macrospore (mak'rdspor) . [Gk. 

makros, large ; sforos, seed.] A 
large anisospore or gamete of 
Sarcodina (zool.) ; one of the larger 
spores of heterosporous plants (&>/.). 

macrosporophore (mak'rospo'rofor) n. 
[Gk. ma&ros, large ; sporos, seed ; 
pherein, to bear.] A leafy lobe 
developing macrosporangia (dot.}. 

macrosporophyll (mak'rospo'rofil) n. 
[Gk. makros, large ; sporos, seed ; 
phyllon, leaf.] Macrosporophore. 

macrosporozoite (mak'rospo'rozo'it) n. 
[Gk. makros, large ; sporos, seed ; 
zoon, animal.] A larger endo- 
gamous sporozoite of Sporozoa 

macrostomatous (mak'rostom'atus) a. 

[Gk. makros, large ; stoma, mouth.] 

With very large mouth. 
macrostylospore (mak'rostl'lospor) n. 

[Gk. makros, large ; stylos, pillar ; 

sporos, seed.] A large spore-like 

stalked body (dot.). 
macrostylous (mak'rostl'lus) a. [Gk. 

makros, large ; stylos, pillar.] With 

long styles (&?/.). 
macrotherm (mak'rothgrm) n. [Gk. 

makros, large ; therme, heat.] A 

tropical plant ; a plant requiring 

heat and moisture (bot.\ 
macrotous (makro'tus)'a. [Gk. makros, 

large ; ous, an ear.] With large 

ears (zool.~). 
macrotype (mak'rotip) n. [Gk. makros, 

large ; L. typus, a typej A modi- 

fied arrangement of Anthozoan 

mesenteries containing more macro- 

mesenteries than the normal micro- 

type (zool.). 

ium) n. [Gk. makros, large ; zoon, 

animal ; gone, generation.] A large 

zoogonidium (dot.). 
macrozoospore (mak'rozo'ospor) . 

[Gk. makros, large ; zoon, animal ; 

sporos, seed.] A large motile 

macula (mak'ula) //., maculae ni.ik'- 

ula) plu. [L. macula, spot.] A 

spot or patch of colour ; a small 

pit or depression ; a tubercle 

macula lutea, the yellow spot of 

the retina, an oval yellowish area 

in the centre of the posterior part 

of the retina at the point of most 

perfect vision (anat.). 




maculate (mak'ulat) a. [L. macula, 
spot.] Spotted. 

maculation (mak'ula'shun) n. [L. 
macula, spot.] The arrangement 
of the spots on a plant or animal 

maculiferous (mak'ulif'erus) a. [L. 
macula, spot ; ferre, to bear.] 

maculose (mak'ulos). Maculate. 

madrepore (mad'rfipor) n. [F. mad- 
repore from L. mater, mother ; Gk. 
poro s, friable stone.] A branching 
stony Coral ; the plate at the ex- 
ternal opening of the stone canal 
in Echinoderms (zool.}. 

madreporic (mad'rSpor'ik) a. [F. 
madrepore, madrepore.] Pert, a 
madrepore or madreporite ; appl. 
body, plate, tubercle, canal 

madreporic canal, see stone canal. 

madreporite (mad'repo'rlt, madrgp'- 
orlt) n. [F. madrepore, madrepore.] 
A flat circular or pentagonal per- 
forated plate marked by grooves, 
lying at the end of an interambu- 
lacral area in many, or free between 
two ambulacral areas in other 
Echinoids, or between the rays in 
the Asteroids ; a modified genital 
plate (zool.}. 

maggot (mag'ot) n. [M.E. magot, a 
grub.] The most lowly organized, 
completely worm-like, insect larva 
withoutappendages or distinct head 

mala (ma'la) n.-, malae (mala) plu. 
[L. mala, the cheek.] Part of the 
maxilla of some Insects, of the 
mandible of certain Myriapods ; 
part of the exterior of the lower 
jaw of Birds (zool.}. 

malacoid (mal'akoid) a. [Gk. mala- 
kos, soft.] Soft in texture. 

malacology (mal'ak61'6jl) n. [Gk. 
malakos, soft ; logos, discourse.] 
The department of zoology dealing 
with Molluscs. 

malacophilous (mal'akof'ilus) a. [Gk. 
malakos, soft ; philein, to love.] 
Pollinating through the agency of 
Gastropods (bot.}. 

malacopterous (mal'akop'te'rus) a. 
[Gk. malakos, soft ; pteron, wing.] 
Soft-finned (zool.}. 

malacostracous (mal'akos'trakus) a. 

[Gk. malakos, soft ; ostrakon, shell.] 
Soft-shelled (zool.}. 

malar (ma'lar) a. [L. mala, cheek.] 
Pert, or in the region of the cheek ; 
n. the zygomatic bone (anat.}. 

male (mal) n. [L. mas, a male.] Pert. 
male or a masculine organism ; 
appl. organs of reproduction, as 
the testes (zool.} ; or fertilizing 
organs of flowers, as stamens (bot.}; 
symbol $ . 

male pronucleus, the nucleus of the 

malleate (mal'eat) a. [L. malleus, 
hammer.] Hammer-shaped ; appl. 
a type of trophi of Rotifer gizzard 

malleoincudal (mal'eoln'kudal) a. [L. 
malleus, hammer ; incus, anvil.] 
Pert, malleus and incus of the 
ear (anat.}. 

malleolar (male'olar) n. [L. dim. of 
malleus, hammer.] The vestigial 
fibula of Ruminants ; a., pert, or in 
the region of the malleolus ; appl. 
arteries, folds, sulcus (anat.}. 

malleolus (male'olus) n. [L. dim. of 
malleus, hammer.] Median and 
lateral malleolus, the lower ex- 
tremity prolongations of tibia and 
fibula respectively (anat.}. 

malleoramate (mal'eora'mat) a. [L. 
malleus, hammer ; ramus, branch.] 
Appl. type of trophi with looped 
manubrium and toothed incus in 
Rotifer gizzard (zool.}. 

malleus (mal'eus) n. [L. malleus, 
hammer.] A part of the Rotifer 
mastax or gizzard ; one of the 
chain of auditory ossicles of Mam- 
mals ; one of the Weberian ossicles 
of Fishes (zool.} 

Malpighian (malplg'ian) a. [After 
Malpighi, of Pisa.] Discovered by 
or named after Malpighi. 

Malpighian body, or corpuscle, in 
spleen, a nodular mass of lymphoid 
tissue ensheathing the smaller 
arteries ; in the kidney, a tuft or 
glomerulus of convoluted capillary 
blood-vessels enclosed in a dilata- 
tion of the uriniferous tubule (anat., 

Malpighian layer, the basal layer 
of the epidermis next to the true 
skin (anat.}. 

Malpighian tubes, slender thread- 




like excretory tubes leading into 
the posterior part of the gut of 

Malpighian tuft, see Malpighian 

maltase (m61'tas) n. (A.S. mealt, 
malt.] A plant ferment which con- 
verts malt-sugar into grape-sugar 

maltose (mol'tos) n. [A.S. mealt, 
malt.] Malt-sugar (phys.~). 

mamelon (mam'Slon) n. [L. mamilla, 
nipple.] A small pimple-like struc- 
ture in the centre of a tubercle of 
an Echinoid interambulacral plate 

mamilla (mamil'a) n, [L. mamilla, 
nipple.] A nipple (anat., zoo!.). 

mamlllary process or tubercle, the 
superior tubercle connected with 
the transverse processes of the lower 
thoracic vertebrae (anat.). 

inanimate (mam'ilat) a. [L.mamilla, 
nipple.] Studded with small pro- 

mamma (mam'a) n. [L. mamma, the 
breast.] The milk-secreting organ 
of Mammals, functionless in the 
male (zoo!.). 

mammal (mam'al) n. [L. mamma, 
the breast.] An animal of the class 
of higher vertebrates of which the 
females suckle the young (zoo!.). 

mammary (mam'ari) a. [L. mamma, 
the breast.] Pert, the breast ; appl. 
arteries, veins, glands, tubules 

mammiferous (mamif'grus) a. [L. 
mamma, the breast ; ferre, to bear.] 
Developing mammae ; milk-secret- 
ing ; mammalian (zoo!.). 

mandible (man'dibl) n. [L. mandibu- 
lum, jaw.] The lower jaw of verte- 
brates, either a single bone or 
composed of a number ; or gener- 
ally, either jaw ; a paired append- 
age connected with the mouth in 

mandibular (mandlb'ular) a. [L. 
mandibulum, jaw.] Pert, the jaw ; 
appl. arch, canal, foramen, fossa, 
nerve, notch (anaf.). 

mandibulate (mandlb'ulat) a. [L. 
mandibulum, jaw.] Having a lower 
jaw ; having functional jaws ; hav- 
ing mandibles (zoo!.). 

mandibuliform (mandib'ullform) a. 

[L. mandibulum, Jaw ; forma, shape.] 
Resembling, or used as a mandible; 
appl. certain insect maxillae (zoo!.). 

mandibulo-hyoid (mandib'ulo-hi'oid) 
a. [L. mandibulum, jaw ; Gk. 
hyoeides, Y-shaped.] In the region 
of the mandible and hyoid (anaf.). 

mandibulo-maxillary (mandib'ulo- 
mak'silari, -maksil'-) a. [L. mandib- 
ulum, jaw ; maxilla, jaw.] Pert. 
maxillae and mandibles of Arthro- 
pods (zool.}. 

manducation (man'duka'shun) n. [L. 
manducare, to chew.] Chewing ; 
mastication (phys.). 

manicate (man'Ikat) a. [L. mani- 
catus, sleeved.] Covered with en- 
tangled hairs or matted scales (dot.). 

manna (man'a) n. [Gk. manna, 
manna.] The hardened exudation 
of the bark of certain trees (hot.} ; 
honey-dew secreted by certain 
Coccidae (zoo!.). 

mantle (man'tl) n. [L. mantellum, a 
cloak.] The outer soft fold of 
integument next the shell of Mol- 
luscs ; a pallium ; a sheath of 
spongoblast cells ; the body-wall 
of Ascidians (zool.}. 

mantle cavity, a space between the 
mantle and body proper (zoo/.). 

mantle cell, a cell of the tapetum 
or investing tissue of a sporangium 

mantle fibres, the spindle fibres of 
a fully formed spindle (emb.). 

mantle layer, a layer of the embry- 
onic medulla spinalis representing 
the future gray columns (emb.). 

mantle lobes, dorsal and ventral 
flaps of the mantle in bivalves 

manual (man'ual) n. [L. manus, 
hand.] A wing-quill borne on the 
manus or hand of Birds ; a primary 
feather (zoo!.). 

manubrial (manu'brial) a. [L. manu- 
brium, handle.] Pert, a manubrium ; 
handle-shaped (zoo!.). 

manubrium (manu'brium) n. [L. 
manubrium, handle.] A cell pro- 
jecting inwards from the shield of 
an antheridial globule of Thallo- 
phytes (dot.) ; a hypostome or coni- 
cal elevation at the distal end of a 
Hydrozoan polyp ; the clapper-like 
portion hanging down from the 




under surface of Medusae (zool.) ; 
the handle-like part of the malleus 
of the ear ; the anterior part of the 
sternum (anat.). 

manns (ma'nus) n. [L. manus, hand.] 
The hand, or part of the fore-limb 
corresponding to it, as found in 
vertebrates from Amphibia up- 
wards (zool.~). 

manyplies, the omasus or psalte- 
rium, the third chamber of the 
stomach of Ruminants so-called 
from its folded structure (zool.). 

marcescent (marses'ent) a. [L. mar- 
cescere, to wither.] Withering but 
not falling off; appl. a calyx or 
corolla persisting after fertilization 

marginal (mar'jmal) a. [L. margo, 
edge.] Pert, at or near the margin, 
edge, or border ; appl. a form of 
nervation (bot.) ; appl. a convolu- 
tion of the frontal lobe (anat.). 

marginal organ or vesicle, a litho- 
cyst (zool.). 

marginal plates, the system of 
plates round the margin of a 
Chelonian carapace (zool.). 

marginalia (mar'jina'lia) n. plu. [L. 
margo, edge.] Prostalia or defen- 
sive spicules on the body surface 
round the osculum (zool.). 

marginate (mar'jinat) a. [L. margo, 
edge.] Having a distinct margin 
in structure or colouring. 

marginicidal (mar'jmisl'dal) a. [L. 
margo, edge ; caedere, to cut.] 
Dehiscing by line of union of 
carpels (bot.). 

marginiform (mar'jmlform) a. [L. 
margo, edge ; forma, shape.] Like 
a margin or border in appearance 
or structure. 

marginirostral (mar'jiniros'tral) a. 
[L. margo, edge ; rostrum, beak.] 
Forming the edges of a bird's bill 

marmorate (mar'morat) a. [L. mar- 
mor, marble.] Of marbled appear- 

marrow (mar'6) n. [M.E. marow, 
pith.] The connective tissue filling 
up the cylindrical cavities in the 
bodies of long bones, and the 
spaces of the cancellous tissue, 
differing in composition in different 

marsupial (marsu'pial) a. [L. marsu- 
pium, a pouch.] Pert, a marsupium ; 
pouch - bearing, as a kangaroo ; 
appl. certain bones in connection 
with the pelvic girdle in certain 

marsupium (marsu'pium) n. [L. 
marsupium, pouch.] Any pouch- 
like structure in which the young 
of an animal complete their de- 
velopment, such as the abdominal 
pouch of Marsupials ; the gill cavi- 
ties of bivalves ; a recess formed 
by diverging spines and a support- 
ing membrane in Stelleroids ; the 
structure protecting the acrocyst in 
Sertularians (zool.). 

masked (mas'kd) a. [F. masque, a 
mask.] Personate, as appl. corolla 

masseter (mase'ter) n. [Gk. masse ter, 
one that chews.] The muscle which 
raises the lower jaw and assists 
in chewing (anat.). 

masseteric (mas'eter'ik) a. [Gk. 
masseter, one that chews.] Pert. 
or near the masseter muscle of the 
cheek ; appl. artery, vein, nerve 

massula (mas'ula) n. [L. massa, 
mass.] A mass of microspores in 
a sporangium of certain Pterido- 
phytes ; a massed group of micro- 
spores in Orchids (bot.). 

niastax (mas'taks) n. [Gk. mas tax, 
the mouth.] The gizzard of Rotifers 

mast cells (Mastzellen of Ehrlich), 
spheroid or ovoid cells of soft proto- 
plasm, very granular, numerous in 
parts where fat is being laid down. 

mastication (mas'tika'shun) ;/. [L. 
masttcare, to chew.] Process of 
chewing food with the teeth till 
reduced to small pieces or a pulp 

masticatory stomach, the gastric 
mill or stomodaeal apparatus of 
Crustaceans for grinding and strain- 
ing food material (zool.). 

mastigium (mastij'ium) n. [Gk. 
mastigion, little whip.] A defen- 
sive posterior lash of certain insect 
larvae (zool.}. 

mastigobranchia (mas'tlgobrang'kla) 
n. [Gk. mastigion, little whip ; 
brangchia, gills.] The epipodite of 




adult Decapoda, a bilobed mem- 
branous lamina extending upwards 
between the gills (zool.}. 

mastoid (mas'toid) a. [Gk. mastos, 
breast; eidos, resemblance.] Nipple- 
shaped ; appl. a process of the 
temporal bone, also cells, foramen, 
fossa, notch (anat.}. 

mastoideosquamous (mastoid'e'6- 
skwa'mus) a. [Gk. mastos, breast ; 
eidos, like ; L. squama, scale.] Pert. 
mastoid and squamous parts of the 
temporal bone (anat.}. 

a'lis) a. [Gk. mastos, breast ; eidos, 
like ; L. humerus, the humerus.] 
A muscle of certain quadrupeds 
connecting mastoid and humerus 

masto-occipital (mas'to-oksip'ital) a. 
[Gk. mastos, breast ; L. occiput, the 
occiput.] Pert, occipital bone and 
the mastoid process of the temporal 

mastoparietal (mas'topari'e'tal) a. 
[Gk. mastos, breast ; L. paries, 
wall.] Pert, the parietal bone and 
the mastoid process of the temporal 

mastotympanic (mas'totimpan'lk) a. 
[Gk. mastos, breast ; tympanon, 
drum.] Appl. part of the tympanic 
cavity's boundary in certain Reptiles 

matrix (ma'triks) n. [L. mater, 
mother.] The ground substance 
of connective tissue ; the part 
beneath the body and root of the 
nail ; the uterus (anaf.) ; the body 
upon which a Lichen or Fungus 
grows (dot.). 

mattula (mat'ula) n. [L. matta, mat.] 
The fibrous network covering the 
petiole bases of palms (dot.}. 

maturation (mSt'ura'shun) n. [L. 
maturus, ripe.] The completion of 
germ-cell development, consisting 
of the reduction of the chromatin, 
usually visible in the polar body 
formation (cyt.}. 

maxilla (maksU'a) n. [L. maxilla, 
jaw.] The jaw ; part of the upper 
jaw beyond the premaxilla ; an 
appendage of most Arthropods 
posterior to the mandible, modified 
in various ways in adaptation to 
function and requirements (zool.). 

maxillary (maksil'ari) a. [L. maxilla, 
jaw.] Pert, or in the region of the 
maxilla or jaw ; appl. artery, nerve, 
process, sinus, tuberosity, vein 

maxillary glands, paired renal or- 
gans opening at the base of the 
maxilla in Crustacea (zool.}. 

maxilliferous (mak'sillf e"rus) a. [L. 
maxilla, jaw \ferre, to carry.] Bear- 
ing maxillae (zool.}. 

maxillifonn (maksil'Iform) a. [L. 
maxilla, jaw ; forma, shape.] Like 
a maxilla (zool.}. 

maxillipede (maksil'iped) n. [L. 
maxilla, jaw ; pes, foot.] An ap- 
pendage, in one, two, or three 
pairs, posterior to the maxillae in 
Arthropods (zool.}. 

maxillpdental (maksil'oden'tal) a. [L. 
maxilla, jaw ; dens, tooth.] Pert. 
jaws and teeth (anaf.). 

maxillojugal (maksll'ojoo'gal) a. [L. 
maxilla, jaw ; jugum, yoke.] Pert. 
jaw and jugal bone (anaf.). 

maxillomandibular (maksH'oman- 
dib'ular) a. [L. maxilla, jaw ; man- 
dibulum, jawj Appl. arch forming 
the jaws of primitive Fishes ; pert. 
maxilla and mandible (anaf.). 

maxillopalatal (maksH'opaTatal) a. 
[L. maxilla, jaw ; palatus, the 
palate.] Pert, jaw and palatal 
bones ; appl. a maxillary process 
of Birds (zool.}. 

maxillopharyngeal (maksirofarln'- 
jeil) a. [L. maxilla, jaw ; Gk. 
pharynx, gullet.] Pert, lower jaw 
and pharynx (anaf.). 

maxillo-premaxillary (maksfl'6-pre'- 
maksirari) a. [L. maxilla, jaw ; 
pre, before.] Pert, the whole of 
the upper jaw ; appl. jaw when 
maxilla and premaxilla are fused 

maxilloturbinal (maksH'otur'blnal) a. 
[L. maxilla, jaw ; turbo, whorl.] 
Pert, maxilla and the turbinals ; 
., a bone arising from the lateral 
wall of the nasal cavity which 
supports the sensory epithelium 

maxillula (maksirula) n. [L. dim. 
of maxilla, jaw.] A first maxilla 
in Crustacea when there are more 
pairs than one (zool.}. 
meatus (mea'tus) n. [L. vteatus, a 




passage.] A passage or channel, 
as the acoustic or auditory, and the 
nasal meatus (anat.}. 

Meckelian cartilage or rod. [After 
Meckel, German anatomist.] The 
lower jaw of lower vertebrates, and 
in the higher the axis round which 
the membrane bones of the jaw are 
arranged and formed (anat.}. 

Meckel's rod or cartilage, Meckelian 
rod or cartilage. 

meconidium (mgk'onid'ium) n. [Gk. 
mekon, poppy.] Sessile or pedicel- 
late extracapsular medusae usually 
lying on the top of the gonangium 
of certain Hydroids (zool.}. 

media (me'dia). [L. medius, middle.] 
A middle structure, such as a layer 
of tissue, a central nervure (anat., 
zool.} ; as a plu., substances of 
various kinds, such as bouillon, in 
which cultures are grown (biol.}. 

mediad (me'diad) adv. [L. medius, 
middle.] Towards but not quite in 
the middle line or axis (anat.}. 

medial (me'dial) a. [L. medius, 
middle.] Situated in the middle. 

median (me'dlan) a. [L. medius, 
middle.] Lying or running in the 
axial plane ; intermediate ; middle. 

mediastinal (me'dias'tmal, -astl'nal) 
a. [L. mediastinus, a servant.] Pert. 
or in the region of the mediastinum; 
appl. cavity, arteries, glands, pleura 

mediastinum (me'dias'tinum, -astl'- 
num) n. [L. mediastinum, servant.] 
The space between the right and 
left pleura in and near the median 
sagittal chest plane ; an incomplete 
vertical septum of the testis (anat.}. 

mediodorsal (me'diodor'sal) a. [L. 
medius, middle ; dorsum, the back.] 
In the dorsal middle line. 

mediopalatine (me'dioparatin) a. [L. 
medius, middle ; palatus, palate.] 
Between the palatal bones ; appl. 
a cranial bone of some Birds (zool.}. 

mediopectoral (me'diopgk'toral) a. 
[L. medius, middle ; pectus, breast.] 
Appl. the middle part of the sternum 

mediostapedial (me'diostape'dial) n. 
[L. medius, middle ; stapes, stirrup.] 
Pert, that portion of the columella 
auris of certain animals external to 
the stapes (anat.}. 

mediotarsal (me'diotar'sal) a. [L. 
medius, middle ; tarsus, ankle.] 
Between the tarsal bones. 

medioventral (me'dioven'tral) a. [L. 
medius, middle ; -venter, the belly.] 
In the middle ventral line. 

medithorax (me'ditho'raks) n. [L. 
medius, middle ; Gk. thorax, the 
breast.] The middle part of the 
thorax ; the mesothorax of Insects 

medium (me'dmm) n., media (me'dia) 
plu. [L. medius, middle.] Any of 
the structures through which a 
force acts, as the refracting media 
of the eyebulb (anat.} ; any of the 
more or less solid substances in 
which cultures are reared or 
tissues are propagated (phys.}. 

medulla (mgdul'a) n. [L. medulla, 
marrow, pith.] Marrow of bones ; 
the central part of an organ or 
tissue (anat.} ; the pith or central 
portion of a stem (hot.}. 

medulla oblongata, the posterior 
portion of the brain continuous 
with the medulla spinalis, or spinal 
cord (anat.}. 

medullary (mgdul'ari) a. [L. medulla, 
pith.] Pert, or in the region of 
the medulla ; appl. axis, artery, 
lamina, membrane, bone, spaces 

medullary canal or cavity, the 
hollow cylindrical portion of a long 
bone containing marrow (anat.} ; 
the neurocoel (emb.}. 

medullary groove, a groove on the 
surface of the medullary plate, 
bounded by folds which, growing 
up, coalesce and convert the groove 
into a canal ; the neurocoel (emb.}. 

medullary keel, a down ward growth 
towards the archenteron, the rudi- 
ment of the central nervous system 
in the development of certain primi- 
tive vertebrates (smb.}. 

medullary layer, a thick subcortical 
layer of the thallus of some Lichens 

medullary plate, the plate-like 
formation of ectoderm cells 
bordering the blastopore of early 
embryo ; the earliest rudiment of 
the nervous system (emb.}. 

medullary rays, a number of strands 
of connective tissue extending be 




tween the pith and the pericycle 

medullary sheath, a ring of pro- 
toxylems round the pith of certain 
stems (dot.) ; a layer of white 
glistening material surrounding 
the axis cylinder of a medullated 
nerve-fibre (zool.). 

medullated (mgdula'tSd) a. [L. 
medulla, pith.] Provided with a 
medullary sheath. 

medullated nerve-fibres, the fibres 
of the white part of the brain and 
spinal cord, consisting of an axis- 
cylinder or neuraxis of primitive 
fibrillae, surrounded by medullary 
sheath, which is in turn covered by 
a delicate membrane, the neuri- 
lemma (anat.). 

medullispinal (mgdul'ispi'nal) a. [L. 
medulla, pith ; spina, the spine.] 
Of the spinal cord. 

medusa (mgdu'sa) n. [Gk. Medousa, 
one who rules.] A jelly-fish (zool.). 

medusiform (medu'siform) a. [Gk. 
Medousa, Medusa ; L. forma, 
shape.] Like a medusa or jelly-fish. 

medusoid (medu'soid) n. [Gk. 
Medousa, Medusa ; eidos, like.] 
A medusa - like free - swimming 
gonophore of Hydrozoa (zool.) ; a., 
like a jelly-fish or medusa (zool.). 

medusome (mSdu'som) n. [Gk. 
Medousa, Medusa ; soma, body.] 
A name given to the medusoid 
stage in the life-history of Obelia 

megagamete (mgg'agamet) n. [Gk. 
megas, large ; gametes, a spouse.] 
A rounded cell regarded as an 
ovum or its equivalent ; developed 
from a megagametocyte after a 
process akin to maturation (zool.). 

megagametocyte (mgg'agame'toslt) 
n. [Gk. megas, large ; gametes, a 
spouse ; kytos, hollow.] A cell 
developed from a merozoite, and 
itself giving rise to a megagamete, 
frequently requiring transference 
to another host before its develop- 
ment can proceed (zool.). 

megakaryocyte (meg'akar'ioslt) n. 
[Gk. megas, large ; karyon, nut ; 
kytos, hollow.] A giant-cell of 
marrow with one large annular 
lobulated nucleus, containing a 
number of nucleoli (anat.). 

megalaesthetes (meYaleVthets) . 
plu. [Gk. megalon, great ; aistheti- 
kos, perceptive.] Sensory organs, 
sometimes in the form of eyes in 
the Placophora (zool.). 

megaloblast (meg'aloblast) n. [Gk. 
megalon, great ; blastos, bud.J A 
large erythroblast (anat.). 

megalogonidlum (mgg'alogonTd'Ium) 
n. [Gk. megalon, great ; gonos, 
offspring.] A large gonidium (dot.). 

megalopa (mfig'alo'pa). Megalops. 

megaloplc (mgg'alop'ik) a. [Gk. 
megalon, great ; ops, eye.] Be- 
longing to the megalops stage 

megalopore (meg'alopor) n. [Gk. 
megalon, great ; poros, a channel.] 
A pore in the dorsal plates in 
Chiton for placing a megalaesthete 
in direct communication with the 
exterior (zool.). 

megalops (me'g'alops) n. [ Gk meg- 
alon, great ; os, eye.] A larval 
stage of certain Crustaceans, as 
crabs, conspicuous by large stalked 
eyes (zool.). 

megalospherlc (mgg'alosfgr'ik) a. 
[Gk. megalon, great ; sphaira, a 
globe.] Of polythalamous Foramin- 
ifer shells, having a megalosphere 
or large initial chamber (zool.}. 

megamere (meg'amer) n. [Gk. megas, 
large ; meros, part.] One of the 
large cells formed after the primary 
divisions of a developing ovum 

meganucleus (mgg'anu'kleus) n. [Gk. 
megas, large ; L. nucleus, kernel.] 
The larger nucleus, or vegetative 
nucleus, of the Infusoria (zool.). 

megasclere (mSg'askler) n. [Gk. 
megas, large ; skleros, hard.] A 
skeletal spicule of the general 
supporting framework, as opp. a 
microsclere (zool.). 

megaspherlc (mgg'asfeVlk). Megalo- 

megasporangium (me'g'asporanjium) 
n. [Gk. megas, large ; sporos, 
seed; anggeion, vessel.] A macro- 
spore-producing sporangium (bot.). 

megaspore (me'g'aspor) n. [Gk. 
megas, great ; sporos, seed.] A 
larger-sized spore of dimorphic 
forms in reproduction by spore- 
formation (zool.) ; the larger spore 




of heterosporous plants, regarded 
as female ; the embryo sac-cell of 
a seed plant (bot.}. 

megasporophyll (meg'aspo'rofil) n. 
[Gk. megas, great ; sporos, seed ; 
phyllon, leaf.] A spore-bearing leaf 
developing megasporangia (bot.}. 

megatherm (meg'atherm) n. [Gk. 
megas, great ; therme, heat.] A 
tropical plant (bot.}. 

megazooid (meg'azo'oid) n. [Gk. 
megas, great ; zoon, animal ; eidos, 
like.] The larger zooid resulting 
from binary or other fission (zool.}. 

megazoospore (meg'azo'ospor) n. [Gk. 
megas, great ; zoon, animal ; sporos, 
seed.] A large zoosppre, as in the 
reproduction of certain Radiolaria 
(zool.') ; a zoogonidium of certain 
Algae (bot.}. 

Meibomian glands, glands of the 
eyelid with a sebaceous secretion 

meiophylly (ml'ofil'I) n. [Gk. melon, 
smaller ; phyllon, leaf.] The sup- 
pression of one or more leaves in 
a whorl (bot.}. 

meiostemonous (ml'ostem'onus) a. 
[Gk. melon, smaller ; stemon, a spun 
thread.] Having fewer stamens 
than petals or sepals (hot.}. 

meiotaxy (ml'otak'si) n. [Gk. melon, 
smaller ; taxis, arrangement.] Sup- 
pression of a whorl or a set of 
organs (bot.}. 

meiotic (mlot'fk) a. [Gk. melon, 
smaller.] Appl. reduction division, 
which see ; also maiotic (cyt.}. 

Meissner's plexus, a gangliated 
plexus of nerve fibres in the sub- 
mucous coat of the small intestine 

melanin (mel'anln) n. [Gk. melas, 
black.] Black or dark-brown pig- 
ment, as of the retina ; cf. haemo- 
zoin (phys.}. 

melanism (mel'anTzm) n. [Gk. me/as, 
black.] Excessive development of 
black pigment in skin or body- 
covering (biol.}. 

melanocyte (mel'anosit) n. [Gk. melas, 
black; kytos, hollow.] A black 
pigmented lymphocyte (phys.}. 

melanospermous (ineTandsper'iniis) a. 
[Gk. melas, black ; sperma, seed.] 
Appl. seaweeds with dark-coloured 
spores (bot.}. 

melanotlc (meTanot'ik) a. [Gk. melas, 
black.] Having black pigment un- 
usually developed. 

melliferous (melif'erus) a. [L. mel, 
honey ; ferre, to carry.] Honey- 
producing (bot.}. 

melliphagous (melif'agus) a. [L. mel, 
honey ; Gk.phagein, to eat.] Feed- 
ing on honey (zool.}. 

mellisugent (mel'Isu'jent) a. [L. mel, 
honey ; sugere, to suck.] Honey- 
sucking (zool.}. 

mellivorous (meliv'orus) a. [L. mel, 
honey ; vorare, to devour.] Feeding 
on honey (zool.}. 

member (mem'ber) n. [L. membrum, 
a member.] A limb or organ of 
the body (zool.} ; a well-defined 
part or organ of a plant (bot.}. 

membrana (membra'na) n. [L. mem- 
brana, a membrane.] A thin film, 
skin or layer of tissue covering a 
part or organ of animal or plant ; 
or a thin skin-like covering of 
cells or unicellular organisms 

membranaceous (mem'brana'shus) a. 
[L. membrana, membrane.] Of the 
consistency or having the structure 
of a membrane (biol.}. 

membrane (mem'bran), a mem- 
brana, which see. 

membrane bone, a bone developing 
directly from membrane without 
passing through a cartilage stage 

membranella (mem'branel'a) n. [L. 
membrana, membrane.] A flapping 
or swinging membrane formed by 
fusion of rows of cilia, found among 
the Protozoa (zool.}. 

membraniferous (mem'branif'erus) a. 
[L. membrana, membrane ; ferre, 
to carry.] Enveloped in or bear- 
ing a membrane. 

membranoid (mem'branoid) a. [L. 
membrana, membrane ; Gk. eidos, 
like.] Resembling membrane. 

membranous (mem'branus) a. [L. 
membrana, membrane.] Resem- 
bling or consisting of membrane ; 
pliable and semitransparent. 

membranous cranium, a mesenchy- 
mal investment enclosing the whole 
brain (emb.}. 

membranous labyrinth, the internal 
ear, separated from the bony cavi- 




ties by perilymph, and itself con- 
taining endolymph (ana/.). 

membranous vertebral column, 
a continuous sheath of mesoderm, 
enveloping notochord and neural 
tube (emb.}. 

membranula (me'mbran'ula) n, [L. 
dim. of membrana, membrane.] A 
concrescence of cilia, as in certain 
Infusoria (zoo/.). 

membranule (mgm'branul) n. [L. 
dim. of membrana, membrane.] A 
small opaque space, in some 
dragon-flies' wings, lying close to 
the body of the insect in the anal 
area of the wing (zoo/.). 

Mendellan, pert, law, factor or 
character which behaves accord- 
ing to the results of Mendel's 

Mendellsm, a law or rule governing 
the inheritance of characters in 
plants and animals discovered by 
Gregor Mendel. This principle 
deals with the inheritance of " unit 
characters," the presence or ab- 
sence of one or other of a pair of 
contrasting characters. It also 
shows that the offspring of organ- 
isms with a pair of contrasting 
characters will be produced in a 
definite ratio. From this law we 
are able to get a more correct and 
scientific definition of "purity of 
a breed." It may be extended to 
deal with groups of characters. 

meningeal (mgn'Inje'al, mgnm'jeal) a. 
[Gk., meninx, a membrane.] Pert. 
or in the region of the meninges ; 
appl. artery, vein, nerve (ana/.). 

meninges (me'nin'jez) n. plu. [Gk. 
meninx, a membrane.] The three 
membranes enclosing the brain and 
spinal cord, from without inwards 
the dura mater, arachnoid and pia 
mater (anat.}. 

meningosis (mgn'ingo'sis) n. [Gk. 
meninx, a membrane.] Attach- 
ment by means of membranes. 

meningo-spinal (mening'go-spl'nal) a. 
[Gk. meninx, a membrane ; L. 
spina, spine.] Pert, the spinal 
cord membranes (anat.}. 

meniscus (mgnis'kus) n., menisci 
(mgnts'kl) plu. [Gk. meniskos, a 
little moon.] Interarticular fibro- 
cartilages found in joints exposed 

to violent concussion, such as wrist 
and knee joints (anat.}. 

mensa (m&n'sa) n. [L. mensa, a 
table.] The chewing surface of a 

menstruation (men'strooa'shun) . 
[L. mensis, a month ; struere, to 
flow.] A monthly discharge from 
the female reproductive organs, 
chiefly in higher mammals (zoo/.). 

mental (mgn'tal) a. [L. mentum, 
chin.] Pert, or in the region of 
the chin ; appl. foramen, nerve, 
spines, tubercle, muscle (anat.} ; 
pert, the mentum of insects ; apj>L 
scale or plate of fish and of reptile 

mentigerous (me'ntij'e'rus) a. [L. 
mentum, chin ; gerere, to carry.] 
Supporting or bearing the mentum 

mentomeckelian (me'n'tome'ke'lian) a. 
[L. mentum, chin ; Ger. Meckel, 
comparative anatomist.] Appl. a 
cartilage bone present in a few 
lower vertebrates at either side of 
the union of the two halves of the 
lower jaw (zoo/.). 

mentum (mgn'tum) n. [L. mentum, 
chin.] The chin (anat.} ; an un- 
divided mouth-part of Insects, con- 
tinuous with submentum or gula 
and posterior to labial palps and 
palpigers ; a projection between 
the head and foot of some Gastro- 
pods (zoo/.). 

mericarp (meYikarp) n. [Gk. meros, 
part ; karpos, fruit.] A one-seeded 
indehiscent part of a schizocarp 

meridional canal, in Ctenophores, a 
canal extending upwards and down- 
wards beneath a swimming-plate, 
into which the adradial canals 
open (zoo/.). 

merism (meYizm) n. [Gk. meros, 
part.] "A repetition of homo- 
logous parts." 

merismatic (meYfzmat'ik) a. [Gk. 
merismos, a partition.] Dividing 
or separating into cells or seg- 
ments ; consisting of meristem, as 
merismatic tissue (oof.). 

merismoid (mgrlz'moid) a. Gk. 
merismos, partition ; eidos, like.] 
With branched pileus (bot.\ 

merispore (mgrfspor) n. [Gk. meros, 




part ; sporos, seed.] A segment or 
spore of a multicellular spore-body 

meristele (mer'istel) n. [Gk. meros, 
part ; stele, pillar.] A separate 
part of a monostelic stem passing 
outwards from stele to leaves ; the 
branch of a stele supplying a leaf 

meristem (meYistgrn) n. [Gk. 
meristes, a divider.] Tissue formed 
of cells all capable of division, as 
found at growing points ; meris- 
matic or meristematic tissue (bot.}. 

merlstematic (mgr'istemat'Ik) a. [Gk. 
meristes, a divider.] Pert, or con- 
sisting of meristem ; appl. tissue, 
cells of growing point ; merismatic 

meristic (mSris'tik) a. [Gk. meristes, 
a divider.] Segmented ; divided 
off into parts (bot.). 

meristic variation, changes in the 
number of parts or segments, and 
in the geometrical relations of the 
parts ; cf. substantive variation 

meristogenetic (me'ris'tqje'ne't'ik) a. 
[Gk. meristes, a divider ; genesis, 
descent.] Developing from mer- 
istem (bot.). 

merithallus (me'rlthal'us) n. [Gk. 
meros, part ; thallos, young shoot.] 
An internode (bot.). 

mermaid's purse, the horny floating 
or fixed egg-envelope of skates and 
sharks (zool.). 

meroblastic (mer'oblas'tik) a. [Gk. 
meros, part ; blastos, bud.] Appl. 
ova which undergo only partial 
segmentation or cleavage in de- 
velopment (zool.) ; developing from 
part of the opsphere only (bot.). 

merocerite (meros'e'rlt) n. [Gk. meros, 
thigh ; keras, horn.] The fourth 
segment of crustacean antennae 

merocyte (mer'oslt) n. [Gk. meros, 
part ; kytos, hollow.] A nucleus 
lying in the yolk, directly below 
the blastoderm in a meroblastic 
ovum (cyt.). 

merogastrula (mer'ogaVtroola) n. 
[Gk. meros, part ; dim. of gaster, 
stomach.] The gastrula formed 
from a meroblastic ovum (zool.). 

m orogenesis (meVoje'n'e'sis) n. [Gk. 

meros, part ; gigncsthai, to produce.] 
Formation of parts ; segmentation. 

merognathite (meVognath'it) n. [Gk. 
meros, thigh ; gnathos, jaw.] The 
fourth segment of a crustacean 
mouth-part (zool.). 

merogony (merog'onT) n. [Gk. meros, 
part ; gone, generation.] Develop- 
ment of normal young of small size, 
from part of an egg, in which there 
was no female pronucleus (zool). 

meroistic (meYois'tlk) a. [Gk. meros, 
part.] Appl. certain insect ovaries 
which produce vitelligenous cells 
in addition to ova (zool.). 

meromorphosis (mer / 6m6r'f6s!s) n. 
[Gk. meros, part ; morphosis, change.] 
Regeneration of a part when the 
new part is less than that lost 

meront (mSront') n. [Gk. meros, 
part ; ons, being.] A uninucleate 
schizont-stage in Neosporidia suc- 
ceeding the planont-stage, which 
multiplies by fission (zool.). 

meroplankton (mer'oplang'kton) n. 
[Gk. meros, part ; plangktos, 
wandering.] Plankton living only 
part-time near the surface (bot., 

meropodite (merop'odit') n. [Gk. 
meros, thigh ; pous, foot.] The 
fourth segment of a thoracic ap- 
pendage in the Crustacea (zool.). 

meros (me'rfis) n. [Gk. meros, thigh.] 
The fourth segment of a crustacean 
appendage (zool.). 

merosomatous (meVosom'atus) a. 
[Gk. meros, part ; soma, body.] 
Appl. ascidiozooids divided into 
two regions, thorax and abdomen 

merosome (mer'osom) n. [Gk. meros, 
part ; soma, body.] A body seg- 
ment, somite, or metamere (zool.). 

merosthenic (me'rosthe'n'ik) a. [Gk. 
meros, thigh ; sthenos, strength.] 
With unusually developed hind- 
limbs (zool.). 

merotomy (merot'dmi) n. [Gk. meros, 
part ; temnein, to cut.] Segmenta- 
tion or division into parts (zool.). 

merozoite (mer'ozo'it) n. [Gk. meros, 
part ; zoon, animal.] A cell, the 
division-product of a schizont in 
Sporozoa (zool.). 

merozoon (mer'6zo'8n) n. [Gk. meros, 




part ; zoon, animal.] A fragment 
of a unicellular animal containing 

Eart of the macronucleus, obtained 
y artificial division (zool.}. 

merrythought, the furcula of birds, 
formed by the coalescence of clav- 
icles (zool.). 

merus (me'rus) n. [Gk. meros, thigh.] 
Meros, which see. 

mesamoeboid (meVame'boid) cells, 
nucleated cells of the blood islands 
from which blood corpuscles are 
derived (emb.). 

mesarch (meVark) a. [Gk. mesos, 
middle ; arche, beginning.] Appl. 
xylem having metaxylem develop- 
ing in all directions from the 
protoxylem, characteristic of ferns ; 
having the protoxylem surrounded 
by metaxylem (bot.\ 

mesaxonic (meYakson'lk) a. [Gk. 
mesos, middle ; axon, axis.] With 
the line dividing the foot, passing 
up the middle digit (zool.). 

mesencephalon (m6s'6nk6f'alon, -s6f-) 
n. [Gk. mesos, middle ; en, in ; 
kephale, head.] The mid-brain, 
comprising corpora quadrigemina 
(bigemina) and cerebral peduncles 

mesenchyma (me'se'ng'kima) n. [Gk. 
mesas, middle ; engchein, to pour 
in.] A mass of tissue, intermediate 
between ectoderm and endoderm 
of a gastrula (emb.). 

mesenchyme (mgse'ng'klm). Mesen- 

mesenterlal (me's'e'nte'rlal, meYgnte'- 
rlal) a. [Gk. mesos, middle ; enteron, 
gut.] Pert, a mesentery ; appl. 
filaments of Actinozoa (zool.). 

mesenteric (meYenteVik, mez'enteYik) 
a. [Gk. tnesos, middle ; enteron, 
gut.] Pert, a mesentery ; appl. 
artery, glands, nerves, veins (anat.). 

mesenterlole (meYgnte'riol, meY- 
Snte'rlol) n. [L. dim. of mesenterium, 
a mesentery.] A fold of peritoneum 
derived from the mesentery, retain- 
ing the vermiform appendix in 
position (anat.). 

mesenterium (me's'e'nte'rTum, meY- 
gnte'rium) n. [L. mesenterium, a 
mesentery.] A mesentery. 

mesenteron (me'se'n'te'rSn) n. [Gk. 
mesos, middle ; enteron, gut.] The 
main digestive cavity of Actinozoa 

and other Coelenterates; the portion 
of the alimentary canal lined by 
endoderm (zool.). 

mesentery (me's'e'nte'r!, mez'e'nte'rl) n. 
[L. mesenterium, a mesentery.] A 
peritoneal fold serving to hold the 
viscera in position : there are three, 
the mesentery proper, the trans- 
verse mesocolon, and the sigmoid 
mesocolon (anat.) ; a muscular par- 
tition, complete or incomplete, ex- 
tending inwards from the body- 
wall in Coelenterates (zool.). 

mesepimeron (m6s'fiplm'6r6n) n. [Gk. 
mesos, middle ; ejbi, upon ; meros t 
part.] The epimeron of the meso- 
thorax of an insect (zool.). 

mesethmoid (me'se'th'moid) a. [Gk. 
mesos, middle ; etJimos, sieve ; eidos, 
like.] Between the two ectethmoid 
bones ; appl. ethmoid plate of 
cranium when it ossifies (anat.) ; 
a median cranial bone of verte- 
brates (zool.). 

mesiad (me'zlid) adv. [Gk. mesos, 
middle.] Towards or near the 
middle plane. 

mesial (me'ziai) a. [Gk. mesos, middle.] 
In the middle vertical or longi- 
tudinal plane. 

meslan (me'zlan) a. [Gk. mesos, 
middle.] Mesial. 

mesoarlum (mSs'oa'rlum) n. [Gk. 
mesos, middle ; oarion, a small egg.] 
A mesovarium. 

mesobenthos (mes'obe'n'thSs) n. [Gk. 
mesos, middle ; benthos, depths.] 
The animal and plant life of the 
sea-bottom when the depth is be- 
tween 100 fathoms and 500 fathoms 
(zool., bot.). 

mesoblast (mes'oblast) . [Gk. mesos, 
middle ; blastos, bud.] The meso- 
derm or middle layer of an embryo 

mesoblastema (mes'oblaste'ma). 

mesoblastlc (mes'oblas'tlk) a. [Gk. 
mesos, middle ; blastos, bud.] Pert. 
or developing from the middle layer 

mesobranchial (mes'bbrang'klal) a. 
[Gk. mesos, middle ; brangchia, 
gills.] Pert, the middle gill-region, 
as in Crustacea (zool.). 

mesobronchus (mes'obrSng'kus) . 
[Gk. mesos, middle ; brongchos. 




wind-pipe.] In birds, the main 
trunk of a bronchus in the lung 
beyond the ventricle : it gives rise 
to secondary bronchi (zoo/.). 

mesocaecum (mes'ose'kum) n. [Gk. 
mesos, middle ; L. caecus, blind.] 
The mesentery connected with the 
caecum (anat.). 

mesocardium (mes'okar'dlum) n. [Gk. 
mesos, middle ; kardia, the heart.] 

- An embryonic mesentery binding 
the heart to the pericardial walls 
(emb.); part of the pericardium 
enclosing veins (venous m.) or 
aorta (arterial m.) (anat.). 

mesocarp (mes'okarp) n. [Gk. mesos, 
middle ; karpos, fruit.] The middle 
layer of the pericarp or coat of a 
fruit (bot.). 

mesocentrous (mes'ose'n'trus)tf. [Gk. 
mesos, middle ; L. centrum, a centre.] 
Ossifying from a median centre 

mesochilium (mes'okil'ium) n. [Gk. 
mesos, middle ; cheilos, a lip.] The 
middle portion of the labellum of 
orchids (bot.). 

mesocoel (mes'osel) n. [Gk. mesos, 
middle ; koilos, hollow.] The second 
of three main parts of the coelom 
of Molluscs (zoo/.). 

mesocolic (mes'okol'ik) a. [Gk. mesos, 
middle ; kolon, the large intestine.] 
Pert, the mesocolon ; appl. lymph 
glands (anat.). 

mesocolon (mes'oko'lon) n. [Gk. 
mesos, middle ; kolon, the large in- 
testine.] A mesentery or fold of 
peritoneum attaching the colon to 
the dorsal wall of the abdomen 

mesocoracoid (mes'okor'akoid) a. [Gk. 
mesos, middle ; korax, crow ; eidos, 
resemblance.] Situated between 
hyper- and hypo-coracoid ; appl. 
a middle part of the coracoid arch 
of certain Fishes (zoo/.). 

mesocycle (mes'oslkl) n. [Gk. mesos, 
middle ; kyklos, a circle.] A layer of 
tissue between xylem and phloem 
of a monostelic stem ; part of the 
conjunctive tissue of the stele (hot.). 

mesoderm (mes'odgrm) n. [Gk. mesos, 
middle ; derma, skin.] The meso- 
blast or embryonic layer lying be- 
tween the ectoderm and endoderm 

mesodermal (mes'oder'mal) a. [Gk. 
mesos, middle ; derma, skin.] Pert. 
derived or developing from meso- 
derm (emb.). 

mesodesm (mes'odezm) n. [Gk. mesos, 
middle ; desma, bond.] Part of the 
mesocycle (bot.). 

mesodont (mes'6d8nt) a. [Gk. mesos, 
middle ; odous, tooth.] Appl. stag- 
beetles having a medium develop- 
ment of mandible projections (zoo/.). 

mesogaster (mes'ogas'te'r) n. [Gk. 
mesos, middle ; gaster, belly.] The 
mesentery proper, or fold of peri- 
toneum supporting the stomach 

mesogastric (mes'ogas'trik) a. [Gk. 
mesos. middle ; gaster, belly.] Pert. 
a mesogaster or mesogastrium ; 
pert, the middle gastric region 

mesogastrium (mes'ogas'trium) n. 
[Gk. mesos, middle ; gaster, belly.] 
The mesentery connecting stomach 
with dorsal abdominal wall in the 
embryo (emb.) ; the middle ab- 
dominal region (anat.). 

mesogloea (mes'ogle'a) n. [Gk. mesos, 
middle ; gloia, glue.] An inter- 
mediate non-cellular layer in 
Sponges and Coelenterates (zoo/.). 

mesognathion (mes'ognath'ion) n. 
[Gk. mesos, middle ; gnathos, jaw.] 
The lateral segment of the maxilla, 
bearing the lateral incisor (anat.). 

mesohepar (mes'ohe'par) n. [Gk. 
mesos, middle ; L. hepar, liver.] The 
mesentery supporting the liver 

mesohydpophytic (mes'ohl'droflt'ik) 
a. [Gk. mesos, middle ; hydor, 
water ; phyton, plant.] Growing in 
temperate regions but requiring 
much moisture (bot.). 

mesolecithal (mes'oleVlthal) a. [Gk. 
mesos, middle ; lekithos, yolk of 
egg.] Appl. eggs with yolk in the 
centre (emb). 

mesology (mes81'ojT) n. [Gk. mesos, 
middle ; logos, discourse.] Bio- 
nomics ; the relation between or- 
ganism and environment. 

mesomere (mes'omer) n. [Gk. mesos, 
middle ; meros, part.] The middle 
zone of the coelomic pouches in 
the embryo ; a mesoblastic somite 
or protovertebra (emb.). 




mesometrium (mes'ome'trium) n. 
[Gk. mesos, middle ; metra, uterus.] 
The mesentery of uterus and con- 
necting tubes (anat.). 
mesomitosis (mes'omito'sis) n. [Gk. 
mesos, middle ; mttos, thread.] 
Mitosis within the nuclear mem- 
brane, without co-operation of cyto- 
plasmic elements ; cf. metamltosis 

mesomyodian (mes'dmlo'dlan) a. [Gk. 
mesos, middle ; ntys, a muscle.] 
Appl. birds with muscles of syrinx 
attached to middle of bronchial 
semi-rings (zoo/.}. 

meson (mes'8n, mez^n) n. [Gk. mesos, 
middle.] The central plane, or 
region of it (zool.). 

mesonephric (mes'oneTrik) a. [Gk. 
mesos, middle ; nephros, kidney.] 
Pert, mesonephros, or mid-kidney; 
appl. duct, tubules (zool.). 
mesonephridium (mes'one'frfd'ium) n. 
[Gk. mesos, middle; nephros, kidney.] 
A nephridium or excretory organ 
of certain invertebrates, derived 
from mesoblast (zool.). 
mesonephros (mes'6neTr5s) n. [Gk. 
mesos, middle ; nephros, kidney.] 
The intermediate part of the ex- 
cretory organ in vertebrate embryos 
it becomes the functional kidney 
in lower Craniata, it atrophies 
in the higher forms (zoo/.) ; the 
Wolffian body (anat.). 
mesonotum (mes'ono'tum) n. [Gk. 
mesos, middle ; noton, the back.] 
The dorsal part of an insect meso- 
thorax (zool.). 

mesoparapteron (mes'6'parap'tSron) n. 
[Gk. mesos, middle ; para, beside ; 
pteron, wing.] The small sclerite 
of the mesothorax of insects (zool.). 
mesopetalum (mes'opfit'alum) n. [Gk. 
mesos, middle ; petalon, a petal.] 
The labellum or lip of an orchid 

mesophragma (mes'ofrag'ma) n. [Gk. 

mesos, middle ; phragma, a fence.] 

A chitinous piece descending into 

interior of insect body with post- 

scutellum for base (zool.). 

mesophryon (mesofrion) n. [Gk. 

mesos, middle ; ophrys, an eyebrow.] 

The elevated median head-region 

of Trilobites (Pal.). 

raesophyll (mes ofil) n. [Gk. mesos, 

middle ; phyllon, leaf.] The inter- 
nal parenchyma of a leaf (bot.). 
mesophyte (mes'oflt) n. [Gk. mesos, 
middle ; phyton, plant.] A plant 
thriving in temperate climates with 
a normal amount of moisture (bot.). 
mesoplankton (mes'6plang'kt6n) n. 
[Gk. mesos, middle ; plangktos, 
wandering.] Floating animal and 
plant life from a hundred fathoms 

mesoplast (mes'oplast) n. [Gk. mesos, 
middle ; plastos, moulded.] A cell 
nucleus (cyt.). 

mesoplastron (mes'6plas'tr5n) n. [Gk. 
mesos, middle ; F. plastron, breast- 
plate.] A plate between hyo- and 
hypo - plastron of certain Turtles 

mesopleuron (mes'oploo'rSn) . [Gk. 
mesos, middle ; gleura, side.] A 
lateral part of an insect mesothorax 

mesopodlal (mes'opo'dlal) a. [Gk. 
mesos, middle ; pous, foot.] Pert. 
a mesopodium (bot., zool.). 
mesopodium (mes'opo'dlum) n. [Gk. 
mesos, middle ; pous, foot.] The 
leaf-stalk or petiole region of a leaf 
(bot.) ; the middle part of a mol- 
luscan foot (zool.). 

mesopraescutum (mes'opresku'tum) 
n. [Gk. mesos, middle ; L. prae, 
before ; scutum, a shield.] The 
praescutum of mesothorax in Insects 

mesopterygium (mes'6pt6rij'Ium) n. 
[Gk. mesos, middle ; pterygion, a 
little wing or fin.] The middle of 
three basal pectoral fin-cartilages 
in recent Elasmobranchs (zool.). 
mesopterygoid (mes'5pt6rTgoid) n. 
[Gk. mesos, middle ;pteryx, a wing ; 
eidos, resemblance.] The middle 
of three pterygoid bone elements of 
Teleosts ; the ectopterygoid (zool.). 
mesorchium (mes&r'klum) n. [Gk. 
mesos, middle ; orchis, a testicle.] 
The mesentery supporting the 
testis, attached to dorsal abdominal 
wall in mammalian embryos ; sus- 
pensory in adult Fishes (zool.). 
mesorectum (mes'b'rgk'tum) n. [Gk. 
mesos, middle ; L. rectus, straight.] 
The mesentery supporting the 
rectum (anat.). 
mesorhlnal (mes'ori'nal) a. [Gk. 




mesos, middle ; rhts, nose.] Be- 
tween the nostrils (zool.). 

mesorhinium (mes'orm'fum) n. [Gk, 
mesos, middle ; rhis, nose.] The 
internarjal surface region of a 
bird's bill (zool.). 

mesosalplnx (mes'osal'pmgks) n. [Gk. 
mesos, middle ; salpingx, a trumpet.] 
The portion of supporting ligament 
stretching from uterine tube to the 
lerel of the ovary (anat.). 

mesoscapula (mes'oskap'ula) n. [Gk. 
mesos, middle ; L. scapula, shoulder- 
blade.] The scapular spine 

mesoscutellum (mes'oskuteTum) n. 
[Gk. mesos, middle ; L. scutellum, 
a small shield.] The scutellum of 
insect's mesothorax (zool.). 

mesoscutum (mes'osku'tum) n. [Gk. 
mesos, middle ; L. scutum, a shield.] 
The scutum of insect's mesothorax 

mesosoma (mes'oso'ma) n. [Gk. mesos, 
middle ; soma, body.] The middle 
part of the body ; the praeabdomen 
of Arthropods, or anterior broader 
part of abdomen (zool.). 

mesosperm (mes'ospgrm) n. [Gk. 
mesos, middle ; sperma, seed.] The 
integument investing the nucellus 
of an ovule (bot.). 

mesospore (mes'ospor) n. [Gk. mesos, 
middle ; sporos, seed.] The inter- 
mediate of three spore coats ; a 
resting-spore stage (bot.). 

mesosporium (mes'ospo'rrum). Meso- 

mesostate (mes'ostat) n. [Gk. mesos, 
middle ; stasis, a standing.] An 
intermediate stage in metabolism 

mesostereom (mes'6st6r'e8m) n. [Gk. 
mesos, middle ; stereos, solid.] The 
middle layer of thecal plates of 
Cystidea (zool.). 

mesosternebra (mes'oste'r'ne'bra) n. 
[Gk. mesos, middle ; sternon, breast- 
bone.] A part of the developing 
mesosternum (emb.). 

mesosternum (mes'osteYnum) n. [Gk. 
mesos, middle ; L. sternum, breast- 
bone.] The middle part of the 
sternum of vertebrates ; the gladi- 
olus (anat.) ; the sternum of the 
mesothorax of Insects (zool.). 

mesostethium (mes'oste'thlum) n. 

[Gk. mesos, middle ; stethos, the 
chest.] A mesosternum (zool.). 

mesostylous (mes'osti'lus) a. [Gk. 
mesos, middle ; stylos, pillar.] Hav- 
ing styles of intermediate length ; 
appl. heterostylous flowers (bot.). 

mesotarsal (mes'otar'sal) a. [Gk. 
mesos, middle ; L. tarsus, ankle- 
joint.] Pert, a mesotarsus of an 
Insect (zool.).^ 

mesotarsus (mes'otar'sus) n. [Gk. 
mesos, middle ; L. tarsus, ankle- 
joint.] A middle-limb tarsus of 
insects (zool.). 

mesothecium (mes'othe'sium, -shium) 
n. [Gk. mesos, middle ; theke, cup.] 
The middle investing layer of an 
anther-sac (bot.). 

mesothelium (mes'othe'lium) n. [Gk. 
mesos, middle ; thele, nipple.] Meso- 
derm bounding the primitive coelom 
and giving rise to muscular and 
connective tissue (anat.). 

mesotherm (mes'othgrm) n. [Gk. 
mesos, middle ; therme, heat.J A 
plant thriving in a moderate heat 

mesothoracic (mes'dthoras'ik) a. [Gk. 
mesos, middle ; thorax, chest.] Pert. 
or in the region of the meso- 
thorax ; appl. a spiracle of Insects 

mesothorax (mes'otho'raks) n. [Gk. 
mesos, middle ; thorax, chest.] The 
middle segment of the thoracic 
region of Insects (zool.). 

mesotriaene (mes'otri'en) n. [Gk. 
mesos, middle ; triaina, a trident.] 
An aberrant type of triaene spicule 

mesotrochal (mesot'rokal) a. [Gk. 
mesos, middle ; trochos, wheel.] 
Appl. an annulate larva with circlet 
of cilia round the middle of the 
body (zool.). 

mesotympanic (mes'otimpan'Ik) a. 
[Gk. mesos, middle ; tympanon, a 
drum.] The symplectic ; one of 
the bones in the suspensory appa- 
ratus of the lower jaw in Fishes 

mesovarlum (mes'ova'rium) n. [Gk. 
mesos, middle ; L. ovarium, an 
ovary.] The mesentery of the 
ovary ; suspensory mesentery of 
Fishes (zool., anat.). 

mesoventral (mes'ovgn'tral) a. [Gk. 




mesas, middle ; L. venter, belly.] 
In the middle ventral region. 
Mesozoic (mes'ozo'ik) n. [Gk. mesos, 
middle ; zoe, life.] The middle or 
secondary group of rock-systems 

metabiosis (met'ablo'sis) n. [Gk. 
me/a, after ; bios, life.] Condition 
in which one organism lives only 
after another has prepared its 
environment and died (biol.}. 

metabolic (mgt'abol'ik) a. [Gk. meta, 
after ; ballein, to throw.] Change- 
able ; appl. chemical changes 
occurring in living organism ; 
metamorphosing (biol.\ 

metabolln (metab'olin) n. [Gk. meta- 
bole, change.] A product of meta- 
bolism (phys.}. 

metabolism (metab'ollzm) n. [Gk. 
metabole, change.] The chemical 
change, constructive and destruc- 
tive, occurring in living organisms 

metabranchial (mgt'abrang^kTal) a. 
[Gk. meta, after ; brangchia, gills.] 
Pert, or in the region of the 
posterior gill region (zoo/.). 

metacarpal (mgt'akar'pal) a. [Gk. 
meta, after ; L. carpus, the wrist.] 
Pert, the metacarpus ; appl. bones, 
articulations, etc. (anat.~). 

metacarpophalangeal (mgt'akar'po- 
falan'jeal) a. [Gk. meta, after; 
L. carpus, wrist ; Gk. phalanx, 
series.] Appl. the articulations be- 
tween metacarpals and phalanges 

metacarpus (mgt'akar'pus) n. [Gk. 
meta, after ; L. carpus, wrist.] 
The skeletal part of the hand 
between wrist and fingers, con- 
sisting of five cylindrical bones 

metachromatinic grains, chroma- 
toid bodies found in cells very 
similar to chromatin in properties 
and characteristics (cyt.). 

metachrosis (met'akro'sis) n. [Gk. 
meta, after ; chrosis, colouring.] 
Ability to change colour by expan- 
sion of pigment cells, as in some 
Fishes and Reptiles (zoo/.). 

metacneme (meYaknem) n. [Gk. 
meta, after ; kneme, the tibia.] A 
secondary mesentery of Zoantharia 

metacoel (mgt'asel) n. [Gk. meta, 
after ; koilos, hollow.] The third 
and posterior part of the coelom 
of Molluscs (zoo/.). 

metacone (met'akon) n. [Gk. meta, 
after ; konos, cone.] The postero- 
external cusp of an upper molar 

metaconid (met'ako'nid) n. [Gk. meta, 
after ; konos, cone ; eidos, resem- 
blance.] The postero-internal cusp 
of a lower molar (zoo/.). 

metaconule (meYako'nul) n. [Gk. 
meta, after ; konos, cone.] The 
posterior secondary cusp of an 
upper molar (zoo/.). 

metacoracoid (met'akSr'akoid) n. 
[Gk. meta, after ; korax, crow ; 
eidos, resemblance.] The posterior 
part of the coracoid (zoo/.). 

metacromion (mSt'akro'mlon) n. [Gk. 
meta, after ; akros, summit ; omos, 
shoulder.] A posterior branch- 
process of the acromion-process of 
the scapular spine (zoo/.). 

metadiscoidal (mgt'adiskoid'al) a. 
[Gk. meta, after ; diskos, a quoit ; 
eidos, resemblance.] Appl. placenta 
in which thevilli are at first scattered 
and later restricted to a disc, as in 
man and monkey (zoo/.). 

metadromous (mgtad'romus) a. [Gk. 
meta, after ; dromos, a running.] 
With primary veins of a segment 
arising from the upper side of the 
midrib (bot.). 

metaesthetism (metgs'thgtlzm) n. 
[Gk. meta, after ; aisthetos, per- 
ceptible by the senses.] The 
doctrine that " consciousness is a 
product of the evolution of matter 
and force." 

metagastric (met'agas'trlk) a. [Gk. 
meta, after ; gaster, belly.] Pert. 
the posterior gastric region (zoo/.). 

metagastrula (m&t'agas'troola) n. 
[Gk. meta, after ; gaster, belly.] A 
modified form of gastrula (zoo/.). 

metagenesis (mgt'ajen'gsis) n. [Gk. 
meta, after ; genesis, descent.] Al- 
ternation of generations, which see. 

metakinesis (met'Skine'sIs) n. [Gk. 
meta, after ; kinein, to move.] The 
middle stage of mitosis, during which 
the chromosomes are grouped in 
the equatorial plate (cyt.}. 

metaloph (met'alof) n. [Gk. meta, 




after; lophos, a crest.] The posterior 
crest of a molar, uniting metacone, 
metaconule, and hypocone (zool.}. 

metamere (mSt'amer) n. [Gk. me/a, 
after ; meros, part.] A body 
segment (zoo/.). 

metameric (m 6 t'amg r'lk) a. [Gk. me fa, 
after ; meros, part.] Pert, metamer- 
ism or segmentation (zool.}. 

metamerism (mStam'Srizm) n. [Gk. 
meta, after ; meros, part.] The 
condition of a body divided up 
into segments more or less alike ; 
segmentation ; zonal symmetry 

metamerized (me'ta'm'e'rizd) a. [Gk. 
meta, after ; meros, part.] Seg- 
mented (zool.}. 

metamitosis (mSt'Smito'sis) n. [Gk. 
meta, after ; mitos, thread.] Mitosis 
in which cytoplasmic and nuclear 
elements are both affected ; cf. 

metamorphosis (mgt'amor'fbsis) n. 
[Gk. meta, beyond ; morphe, form.] 
Change of form and structure under- 
gone by an animal from embryo to 
adult stage, as in Insects (zool.} ; 
interference with normal symmetry 
in flowers (bot.} ; internal chemical 
change (phys.}. 

metamps (me'tamp's, me'tamps) n. 
plu. [Gk. meta, after ; morphe, 
form.] Different forms of the same 
species, as in certain Sponges (zool.}. 

metanauplius (mgt'anop'lius). [Gk. 
meta, after ; L. nauplius, a kind of 
shell-fish.] The larval stage of 
Crustacea succeeding the nauplius 
stage (zool.}. 

metanephric (meYaneTrik) a. [Gk. 
meta, after ; nephros, a kidney.] 
Pert, or in the region of the hind- 
kidney (emb.}. 

metanephros (m6t'angf'r6s) n. [Gk. 
meta, after ; nephros, a kidney.] 
The organ arising behind the 
mesonephros and replacing it as 
the functional kidney of fully- 
developed amniotes (zool.}. 

metanotum (mgt'ano'tum) n. [Gk. 
meta, after ; noton, back.] The 
notum or tergum of the meta- 
thorax of Insects (zool.}. 

metanucleus (me't'anu'kleus) n. [Gk. 
meta, after ; L. nucleus, a kernel.] 
A term appl, by Haecker to the 

egg-nucleus after its extrusion from 
the germinal vesicle (cyt.}. 

metapeptone (met'apep'ton) n. [Gk. 
meta, after ; peptos, cooked.] A 
product of the action of gastric 
juice on albumins (phys.}. 

metaphase (meYafaz) n. [Gk. meta, 
after ; phainein, to appear.] The 
stage in mitosis in which the 
chromosomes are split up in the 
equatorial plate (cyt.}. 

metaphery (mgtaf'grl) . [Gk. meta, 
beyond ; pherein, to bear.] Dis- 
placement of organs (bot.}. 

metaphloem (mgt'aflo'gm) n. [Gk. 
meta, after ; phloos, bark.] The 
phloem of secondary xylem (bot.}. 

metaphragma (mSt'afr&g'ma) n. [Gk. 
meta, after ; phragma, a fence.] 
An internal metathoracic septum 
in Insects (zool.}. 

metaphyte (mgt'afit) n. [Gk. meta, 
after ; phyton, plant.] A multi- 
cellular plant (bot.}. 

metaplasia (met'apla'zia) n. [Gk. 
meta, after ; plasis, moulding.] 
Conversion of tissue from one 
form to another, as in ossification 

metaplasia (metap'lasts) n. [Gk. 
meta, after ; plasis, moulding.] 
The mature period in the life of 
an individual (phys.}. 

metaplasm (mgt'aplazm) n. [Gk. 
meta, after ; plasma, something 
moulded.] The lifeless ingredients 
of protoplasm, as opp. to the living 
material (cyt.}. 

metaplastic (mgt'aplas'tik) a. [Gk. 
meta, after ; plastos, moulded.] 
Pert, metaplasia or metaplasm 

metaplastic bodies, grains or 
granules of protoplasm which are 
stages or products of metabolism 
and not true protoplasm (cyt.}. 

metapleural (met'aploo'ral) a. [Gk. 
meta, after ; pleura, a side.] Pos- 
teriorly and laterally situated ; 
pert, a metapleure or metapleuron 

metapleure (meYaploor) n. [Gk. 
meta, after ; pleura, a side.] An 
abdominal or ventro-lateral fold of 
integument of certain of the lowest 
vertebrates (zool.}. 

metapleuron (mSt'aploor'Sn) n. [Gk. 




meta, after ; pleura, a side.] The 
pleuron of an insect metathorax 

metapneustic (met'apnu'stik) a. 
[Gk. meta, after ; pneuma, breath.] 
AppL insect larvae with only the 
terminal pair of spiracles (zool.). 

metapodeon (met'apo'deon) n. [Gk. 
meta, after ; pous, foot.] That part 
of an insect's abdomen behind the 
petiole or podeon (zool.). 

metapodeum (mfit'apo'deum). Meta- 

metapodial (meYapo'dial) a. [Gk. 
meta, after ; pous, foot.] Pert, a 
metapodeon or metapodium (zool.). 

metapodium (met'apo'dium) n. [Gk. 
meta, after ; pous, foot.] The 
posterior portion of a molluscan 
foot ; the portion of the foot 
between tarsus and digits ; in 
four-footed animals, the meta- 
carpus and metatarsus (zool.). 

metapolar cells, the second circlet 
of cells of the polar cap of the 
rhombogen of Rhombozoa. 

metapophysis (meYapof'isis) n. [Gk. 
meta, after ; apo, from ; phyein, to 
grow.] A prolongation of a verte- 
bral articular process developed 
in certain vertebrates (zool.} ; the 
mammillary process (anat.). 

metapore (met'apor) n. [Gk. meta, 
after ; poros, a channel.] The 
medial aperture in the roof of the 
fourth ventricle of the brain ; 
Magendie's foramen (anat.). 

metapostscutellum (met'apostsku- 
teTum) n. [Gk. meta, after ; L. 
post, after ; scutellum, a small 
shield.] The post-scutellum of 
an insect metathorax (zool.). 

metapraescutum (met'apresku'tum) 
n. [Gk. meta, after ; L.prae, before ; 
scutum, shield.] The praescutum 
of an insect meta-thorax (zool.). 

metapterygium (meYapte'rlj'ium) n. 
[Gk. meta, after ; pterygion, a little 
wing.] The posterior basal fin- 
cartilage or bone, either pectoral 
or pelvic, of recent Elasmobranchs 

metapterygoid (mt'apter'fgoid) tt. 
[Gk. meta, after ; pteryx, wing ; 
eidos, resemblance.] The posterior 
of three pterygoid elements in 
certain lower vertebrates (zool.). 

metarachis (mgt'aralrts) n. [Gk. meta, 
after ; rhachis, a spine.] The face 
of Pennatulacea which coincides 
with the sulcar aspect of the ter- 
minal zooid, otherwise the so-called 
dorsal surface (zool.). 

metascutellum (met'askuteTum) n. 
[Gk. meta, after ; L. scutellum, a 
small shield.] The scutellum of an 
insect metathorax (zool.). 

metascutum (mSt'asku'tum) n. [Gk. 
meta, after ; L. scutum, shield.] 
The scutum of an insect meta- 
thorax (zool.). 

metasitlsm (mSt'asit'Izm) n. [Gk. 
meta, after ; sitos, food.] The ac- 
quisition of a cannibalistic mode 
of life (zool.). 

metasoma (mSt'aso'ma) . [Gk. meta, 
after ; soma, body.] The posterior 
body-region of Arachnids (zool.). 

metasomatic (met'asomat'lk) a. [Gk. 
meta, after ; soma, body.] Pert. 
or situated in the metasoma (zool.). 

metasperm (met'aspe'rm) n. [Gk. 
meta, after ; spertna, seed.] A plant 
having seeds in a closed ovary ; an 
angiosperm (bot.). 

metastasis (mgtas'tasis) n. [Gk. 
meta, after ; stasis, standing.] Meta- 
bolism ; transference of function 
from one organ to another (phys.). 

metastatlc (meVastat'ik) life-history 
that of certain Trematodes in which 
the young form after entering the 
intermediate host, metamorphoses 
into the adult, after which the 
intermediate host is swallowed by 
the final host (zool.). 

metasternum (mgt'asteVnum) . [Gk. 
meta, after ; sternon, breast-bone.] 
The sternum of insect metathorax ; 
the posterior sternal part of Anura ; 
the xiphoid or ensiform process, 
the posterior part of the sternum 
of higher vertebrates (zool.). 

metasthenic (meYasthenlk) a. [Gk. 
meta, after ; sthenos, strength.] 
With well-developed posterior part 
of the body (zool.). 

metastlgmate (meYastlg'mat) a. [Gk. 
meta, after ; stigma, mark.] Hav- 
ing posterior tracheal openings or 
stigmata, as in Mites (zool.). 

metastoma (meYasto'ma) n. [Gk. 
meta, after ; stoma, mouth.] Thetwo- 
lobed lower lip of Crustacea (zool.). 




metatarsal (meYatar'sal) a. [Gk. 
meta, after ; L. tarsus, the ankle.] 
In the region of the tarsus ; appl. 
arteries, veins, etc. ; pert, the meta- 
tarsal bones (zool., anat.}. 

metatarsophalangeal (me't'atar'so- 
falan'jeal) a. [Gk. me fa, after ; L. 
tarsus, ankle ; Gk. phalanx, troop.] 
Appl. articulations between the 
metatarsus and phalanges of the 
foot (anat.}. 

metatarsus (met'atar'sus) n. [Gk. 
meta, after ; L. tarsus, ankle.] The 
part of the foot between the ankle 
and toes (anat.}. 

rnetathalamus (met'atharamus) n. 
[Gk meta, after; thalamos, chamber.] 
The geniculate bodies of the brain 

metathorax (met'atho'raks) n. [Gk. 
meta, after ; thorax, the chest.] The 
posterior segment of the thorax 
of Insects (zool.}. 

metatrophic (meYatrof'ik) a. [Gk. 
meta, after ; trofihe, nourishment.] 
Living on decaying organic matter 

metaxylem (mSt'azi'lem) n. [Gk. 
meta, after ; nylon, wood.] Second- 
ary xylem with thick walled cells 

metazoaea (mgt'azo'ea) n. [Gk. meta, 
after ; zoe, life.] A larval stage of 
Crustacea between zoaea and mega- 
lopa stages (zool.}. 

metazoon (mSt'azo'on) n. [Gk. meta, 
after ; zoon, animal.] A multicellu- 
lar animal (zool.}. 

metencephalon (met'enkef'alon, -sef-) 
n. [Gk. meta, after ; en, in ; kephale, 
head.] The hind-brain or cere- 

metenteron (meten'teron) n. [Gk. 
meta, after ; enteron, gut.] An 
intermesenteric chamber of a sea- 
anemone or other Coelenterate 

metepimeron (mSt'e'pim'gron) n. [Gk. 
meta, after ; epi, upon ; meros, part.] 
The epimeron of an insect meta- 
thorax (zool.}. 

metepisternum (met'e'pisteVnum) n. 
[Gk. meta, after ; epi, upon ; sternon, 
breast-bone.] The episternum of 
an insect metathorax (zool}. 

methaemoglobin (mgthe'moglo'bm) ;/. 
[Gk. meta, after ; haiina, blood ; L. 

globus, a globe.] A product of 
blood decomposition (phys.}. 

metochy (met'oki) n. [Gk. metoche, 
a sharing.] The relationship be- 
tween a neutral guest insect and its 
host (zool.}. 

metoecious (mSte'shus) a. [Gk. meta, 
after ; oikos, a house.] Metoxenous 
or heteroecious (dot.}. 

metope (meYope) n. [Gk. metopon, 
forehead.] The middle frontal 
portion of a Crustacean (zool.}. 

metopic (metop'ik) a. [Gk. metopon, 
forehead.] Pert, the forehead ; 
appl. the frontal suture (anat.}. 

metosteon (mStos'teon) n. [Gk. meta, 
after ; osteon, bone.] A posterior 
sternal ossification in birds (zool.}. 

metovum (meto'vum) n. [Gk. meta, 
after ; L. ovum, an egg.] An egg- 
cell surroundedbynutritive material 

metoxenous (metok'sgnus) a. [Gk. 
meta, after ; xenos, a guest.] Para- 
sitic on different hosts at different 
stages in life-history (dot.}. 

micella (miseTa) n. [L. dim. of mica, 
morsel.] An ultimate supra-mole- 
cular unit of a cell. See hypo- 
thetical units. 

micraesthetes (mlkres'thets) n. plu. 
[Gk. mikros, small ; aesthetikos, per- 
ceptive.] The smaller sensory 
organs of Placophora (zool.}. 

microbe (mi'krpb) n. [Gk. mikros, 
small ; bios, life.] A bacterium ; a 

microbiology (ml'kroblpl'oj!) n. [Gk. 
mikros, small ; bios, life ; logos, dis- 
course.] Bacteriology. 

microcalthrops (ml'krokal'throps) n. 
[Gk. mikros, small ; A.S. coltraeppe, 
a kind of thistle.] A primitive 
tetraxon, or euaster with four 
persistent rays (zool.}. 

microcentrum (mi'krosen'trum) . 
[Gk. mikros, small ; L. centrum, 
centre.] The dynamic centre of 
a cell composed of centrosomes 

microconjugant (ini'krdkon'joogant) //. 
[Gk. mikros, small ; L. conjugare, 
to unite.] A motile ciliated free- 
swimming conjugant or gamete 
which attaches itself to a macro- 
conjugant and fertilizes it (zool.}. 

microconidium (mi'krbkonid'ium) n. 




[Gk. mikros, small ; font's, dust.] 
A comparatively small conidium 

microcyst (mf kroslst) n. [Gk. mikros, 
small ; kystis, bladder] A resting- 
spore stage of slime Fungi (hot.}. 

microcytase (mfkrosftas) n. [Gk. 
mikros, small ; kytos, hollow.] The 
enzyme of microphages or smaller 
leucocytes (phys.). 

microcytes (mf kroslts) n. plu. [Gk. 
mikros, small ; kytos, hollow.] 
Blood-corpuscles about half the 
size of erythrocytes, numerous in 
diseased conditions (phys.). 

microdont (mfkrodont) a. [Gk. 
mikros, small ; odous, a tooth.] 
With comparatively small teeth 

microgamete (mfkrogamet') n. [Gk. 
mikros, small ; gametes, a spouse.] 
The smaller of two conjugant 
gametes, regarded as male (zool.). 

microgametocyte (mfkrogame'toslt) 
n. [Gk. mikros, small ; gametes, a 
spouse ; kytos, hollow.] A cell 
developed from a merozoite in 
certain Protozoa, and giving rise 
to a microgamete (zool.). 

microgamy (mlkrQg'amT) n. [Gk. 
mikros, small ; gamos, marriage.] 
Syngamy between the smallest in- 
dividuals, produced by fission or 
gemmation, as in Foraminifers 

inicrogonidium (ml'krogonld'ium) n. 
[Gk. mikros, small ; gonos, off- 
spring.] A comparatively small 
gonidium (dot.) ; a male gamont or 
gametocyte (zool.). 

mlcromere (mfkromer) n. [Gk. 
mikros, small ; meros, part.] A 
cell of the upper or animal hemi- 
sphere in meroblastic and other 
eggs (emb.). 

micromerozoite (ml'kromeYozoit) n. 
[Gk. mikros, small ; meros, part ; 
zoon, animal.] A cell derived from 
a raicroschizont and developing 
into a gametocyte in Haemo- 
sporidia (zool.). 

micromesentery (mf krome's'e'nte'rl) n. 
[Gk. mikros, small ; mesos, middle ; 
enteron, gut.] A secondary incom- 
plete mesentery in Zoantharia 

micron (mi'kron) /;. [Gk. mikros, 

small.] One-thousandth part of a 
millimetre, symbol M, used in 
measurement of diameters of cor- 
puscles, etc. (phys.). 

micront (mfkront) n. [Gk. mikros, 
small ; ons, being.] A small cell 
formed by schizogony, itself giving 
rise to microgametes in Neo- 
sporidia (zool.). 

micronucleus (mfkr6nu'kleus). [Gk. 
mikros, small ; L. nucleus, a kernel.] 
The smaller nucleus of many Proto- 
zoa, lying in close proximity to the 
meganucleus (zool.). 

micro-organism (mfkro-6r'ganizm) n. 
[Gk. mikros, small ; organon, an 
instrument.] A microscopic organ- 
ism ; a bacterium or microbe. 

microphages (ml'krofa'jez) n. plu. 
[Gk. mikros, small ; phagein, to 
eat] Leucocytes possessing the 
enzyme microcytase (phys.). 

microphagocyte (mi'krofag'oslt) n. 
[Gk. mikros, small ; phagein, to 
eat ; kytos, hollow.] A microphage 
or small phagocyte of blood (phys.). 

microphyllous (mf krofil'us) a. [Gk. 
mikros, small ;phyllon, leaf.] With 
small leaves (bot.). 

microphyte (mf kroflt) n. [Gk. mikros, 
small ; phyton, plant.] A micro- 
scopic plant (bot.). 

microphytology (mfkrofltol'qjl) n. 
[Gk. mikros, small ; phyton, plant ; 
logos, discourse.] The science of 
microphytes ; vegetable bacteri- 
ology (bot.). 

micropodous (mikrSp'odus) a. [Gk. 
mikros, small ; pous, foot.] With 
rudimentary or small foot or feet. 

micropore (mf kropor) n. [Gk. mikros, 
small ; poros, a channel.] A small 
pore in a Chiton shell containing a 
sense-organ (zool.). 

inicropterism (mlkrop'terizm) n. [Gk. 
mikros, small ; pteron, wing.] Con- 
dition of having unusually small 
wings, as in some insects (zool.). 

micropterous (mlkrop'tgrus) a. [Gk. 
mikros, small ; pteron, a wing.] 
Having small hind wings invisible 
till tegmina are expanded, as in 
some insects ; with small or rudi- 
mentary fins (zool.). 

micropyle (mfkropll) n. [Gk. mikros, 
small ; pyle, a gate.] The aperture 
for admission of pollen-tube at the 




ovule apex (dot.) ; the aperture in 
the egg-membrane for admission 
of spermatozoon ; a pore in the 
spongin-coat of Sponges for escape 
of gemmules (zoo). 

micropyle apparatus, raised pro- 
cesses or porches, sometimes of 
very elaborate structure, developed 
round the micropyle of certain 
insect eggs (zool.). 

microrhabdus (ml'krorab'dus) n. [Gk. 
mikros, small ; rhabdos, a rod.] 
A minute monaxon or rod-like 
spicule (zool.). 

microschizont (inl'kroshl'zont) n. [Gk. 
mikros, small ; schizein, to cut.] A 
male schizont of certain Protozoa 

microsclere (ml'kroskler) n. [Gk. 
mikros, small ; skleros, hard.] One 
of sponge spicules found lying 
scattered freely in the tissues 

microseptum (ml'krosep'tum) n. [Gk. 
micros, small ; L. septum, parti- 
tion.] An incomplete mesentery 
of Zoantharia (zool.). 

microsmatic (ml'krosmat'ik) a. [Gk. 
mikros, small ; osme, smell.] With 
feebly-developed sense of smell 

microsome (ml'krosom) n. [Gk. 
micros, small ; soma, body.] The 
granule of protoplasm as opposed 
to the ground-substance (cyt.). 

microsphere (ml'krosfer) n. [Gk. 
mikros, small ; sphaira, a globe.] 
The initial chamber of Foramin- 
ifera when very small (zool.). 

microspheric (mi'krosfgr'ik) a. [Gk. 
mikros, small ; sphatra, a globe.] 
Appl. Foraminifera when the initial 
chamber of the shell is small 

n. [Gk. mikros, small ; sporos, seed ; 
anggeion, vessel.] A sporangium 
bearing a number of microspores 

microspore (mlkrospor) n. [Gk. 
mikros, small ; sporos, seed.] The 
spore developed in a microspor- 
angium of heterosporous plants 
(bot.) ; a smaller anisospore of 
Sarcodina (zool.). 

microsporophore (ml'krospo'rofor) n. 
[Gk. micros, small ; sporos, seed ; 

pherein, to bear.] A microspor- 
angium (dot.). 

microsporophyll (rm'krospo'rofll) n. 
[Gk. mikros, small ; sporos, seed ; 
phyllpn, leaf.] A microsporangium- 
bearing leaf (bot). 

microsporozoite (ml'krospo'rozo'it) n. 
[Gk. mikros, small ; sporos, seed ; 
zoon, animal.] A smaller endo- 
genous sporozoite of Sporozoa(sw/.). 

microstome (mi'krostom) n. [Gk. 
mikros, small ; stoma, mouth.] A 
small opening or orifice (zool.). 

microstylospore (ml'krostl'lospor) n. 
[Gk. mikros, small ; stylos, pillar ; 
sporos, a seed.] A comparatively 
small stylospore (dot.). 

microstylous (mi'krostl'lus) a. [Gk. 
mikros, small ; stylos, pillar.] Hav- 
ing short styles ; appl. heterostylous 
flowers (bot.).- 

microtherm (inl'krotherm) n. [Gk. 
mikros, small ; therme, heat.] A 
plant of the north temperate zone 

microtype (mi'krotlp) n. [Gk. mikros, 
small ; L. typus, type.] The normal 
arrangement of mesenteries in 
Anthozoa (zool.). 

microzooid (mi'kroz5'oid) n. [Gk. 
mikros, small ; zoon, animal ; eidos, 
resemblance.] A free-swimming 
motile ciliated bud of Vorticella 
and other Protozoa (zool.). 

microzoospore (ml'krozd'ospor) n. 
[Gk. mikros, small ; zoon, animal ; 
sporos, seed.] A small planogamete 
(bot.); a small anisospore of Radio- 
larians (zool.). 

microzyma (mi'krozl'ma) n. [Gk. 
mikros, small ; zyme, leaven.] A 
biophore or idioblast,a hypothetical 
ultimate unit (biol.). 

microzyme (ml'krozlm) n. [Gk. mikros, 
small ; zyme, leaven.] A micro- 
organism of fermenting or decom- 
posing liquids (phys.). 

mid-body, a cell plate or group of 
granules in the equatorial region 
of the spindle in the anaphase of 
mitosis (cyt.). 

mid-brain, the middle zone of the 
primitive or embryonic brain ; the 
mesencephalon of adults, consisting 
of the cerebral peduncles, the cor- 
pora quadrigema, and the aque- 
ductus Sylvii (anat.). 




mid-rib, the large central vein of a 
leaf, the continuation of the petiole 

midriff (mid'rif) n. [A. S. mid, middle ; 
hrif, the belly.] The diaphragm or 
muscular partition between the 
thoracic and abdominal cavities 
(anat., zool.}. 

Miescher's tubes, see Ralney's 

migration (migra'shun) n. [L. 
migrare, to transfer.] Change of 
habitat, according to climate or 
food-supply, observable chiefly in 
birds, also in reindeer, bats, certain 
fishes, etc. (zool.}. 

migratory cell, an amoeboid cell or 
leucocyte of the blood. 

miliary (mil'iar!) a. [L. milium, 
millet.] Of granular appearance ; 
small and numerous (zool.}. 

milk-teeth, the first dentition of 
Mammals, shed soon after or before 

milt (milt) . [A.S. tnilte, the spleen.] 
The spleen. 

milt (milt) n. [A corruption of milk, 
due to confusion with milt, the 
spleen.] The soft roe, or male 
generative organ of Fishes. 

mimetic (mfmgt'ik) a. [Gk. mimet- 
ikos, imitative.] Appl. animals 
and plants which practise mimicry 

mimic (mim'lk) v. [Gk. mimikos, 
imitating.] To assume, usually for 
protection, the habits, colour, or 
structure of another organism 

mimicry (mim'ikri) n. [Gk. mimikos, 
imitative.] Assumption of resem- 
blance in colour or structure as a 
means of self-protection (dial.}. 

mine (mm) n. [L. minare, to con- 
duct.] A tunnel or gallery con- 
structed by an insect (zool.}. 

minimus (min'imus) n. [L. minimus, 
least.] The fifth digit of hand or 

Miocene (ml'osen) a. [Gk. melon, 
less ; kainos, recent.] Appl. the 
eleventh of the thirteen rock- 
systems, and belonging to the 
Cainozoic or Tertiary group (pal.}. 

miostemonous, meiostemonous 

miracidium (mTr'asTd'ium) n. [Gk. 

dim. of meirakion, a stripling.] 
The ciliated embryo or youngest 
stage in the life-history of a Trema- 
tode (zool.}. 

mitochondria (mi'tokon'dria) n. plu. 
[Gk. mitos, thread ; chondros, grain.] 
Ergastoplasmic granulations of 
protozoan protoplasm ; sphero- 
plasts (zool.} ; a rounded mass of 
granules or fibrils near the nucleus 
of pancreas cells (anat.}. 

mitochondrial sheath, an envelope 
containing mitochondrial granules 
sheathing the spiral thread of a 
spermatozoan body or connecting 
piece (emb.}. 

mitome (ml'tom) n. [Gk. mitos, 
thread.] The reticulum of cell- 
protoplasm, as opposed to ground- 
substance (biol.}. 

mltoschisis (mitos'krsls) n. [Gk. 
mitos, thread ; schizein, to cleave.] 
Indirect nuclear division ; mitosis 

mitosis (mito'sts) n. [Gk. mitos, 
thread.] Indirect or karyokinetic 
nuclear division, with chromosome- 
formation, spindle-formation, and 
with or without centrosome activity, 
and final reduction of the chromo- 
somes (cyt.}. 

mitosome (mit'osom) n. [Gk. mitos, 
thread ; soma, body.] A body 
arising from the spindle-fibres of 
secondary spermatocytes, eventu- 
ally said to form the connecting 
piece and tail envelope of the 
spermatozoon (zool.}. 

mitotic (mitot'ik) a. [Gk. mitos, 
thread.] Pert, or produced by 
mitosis ; appl. division, figure, 
phase (biol.}. 

mitra (mi'tra) n. [L. mitra, head- 
band.] A helmet-shaped part of 
calyx or corolla ; the mitriform 
pileus of certain Fungi (bot.}. 

mitral cells, pyramidal cells with 
thick basal dendrites, found in the 
molecular layer of the olfactory 
bulb (anat.}. 

mitral valve, the bicuspid valve, 
guarding the left auriculo-ven- 
tricular orifice of the heart (anat.}. 

mitriform (mit'riform) a. [L. mitra, 
head-band ; forma, shape.] Mitre- 

mixipterysrium (mlk'sIpteYIj'Ium) //. 




EGk. mtxts, mixing ; pterygion, a 
ittle wing or fin.] The clasper of 
male Elasmobranchs, the medial 
lobe of the pelvic fin (zool.}. 
mixotrophic (mik'sotrofik) a. [Gk. 
mixis, mixing; trephein, to nourish.] 
Combining holophytic with sapro- 
phytic nutrition (zool.} ; obtaining 
part of the nourishment from an out- 
side source ; partly parasitic (bot.}. 
modiolus (modl'olus) n. [L. modiolus, 
a small measure.] The conical 
central axis of the cochlea of the 
ear (anat.}. 

molar (mo'lar) a. [L. molere, to 
grind.] Adapted for grinding, as 
appl. teeth ; appl. certain buccal 
glands (anat.}. 

molecular hypothesis, the supposi- 
tion that muscle and nerve are 
composed of molecules or particles, 
like the molecules of a magnet, 
with positive and negative surfaces 

molecular layer, the external layer 
of the cortex of cerebrum and cere- 
bellum ; a layer of the olfactory 
bulb (anat.}. 

molluscoid (molus'koid) a. [L. mol- 
litscus, soft ; Gk. eidos, like.] Re- 
sembling a Mollusc ; charactetTsAc^ 
of a Mollusc (zool.}. 
monacanthid (mon'akan'thid) a. ' [Gk. 
monos, alone ; akantha, (fhoftrf:^ 
With one row of ambulacral spines, 
as certain Starfishes (zool.}. 
monactinal (monak'tlnal) a. [Gk. 
monos, alone ; aktis, ray.] Appl. 
a monactine or single-rayed spicule 

monactinellid (monak'tinel'id) a. [Gk. 
monos, alone ; aktis, ray.] Contain- 
ing uniaxial spicules only, as 
certain Sponges (zool.}. 
monad (mo'nad) n. [Gk. monas, a 
unit.] A primitive organism or 
organic unit; a flagellula form of 
Protozoan (biol.}. 

monadelphous (monadel'fus) a. [Gk. 
monos, single ; adelphos, brother.] 
Having the stamens united into 
one bundle by union of their fila- 
ments (bot.}. 

monadiform (monad'iform) a. [Gk. 
monas, a unit ; L. forma, shape.] 
Like a flagellate Protozoan (zool.}. 
monandrous (monan'driis) a. [Gk. 

monos, alone ; aner, male.] Having 
only one stamen (bot.}. 
monarch (mon'ark) a. [Gk. monos, 
alone ; arche, beginning.] With 
only one protoxylem (bot.}. 
monaster (monas'ter) n. [Gk. monos, 
alone ; aster, star.] The astral 
arrangement of the V-shaped 
chromosomes at the end of the 
prophase of mitosis (cyt.}. 
monaxial (monak'sial) a. [Gk. monos, 
alone ; axon, axis.] Having one ' 
line of axis ; uniaxial (biol.}; having 
the inflorescence developed on the 
primary axis (bot.}. 

monaxon (monak'son) n. [Gk. monos, 
alone ; axon, axis.] A type of 
spicule built upon a single axis 

monaxonic (mon'akson'ik) a. [Gk. 
monos, alone ; axon, axis.] Elon- 
gate ; appl. types of Protozoa with 
one long body-axis (zool.}. 

monembryonic (monem'brlon'ik) a. 
[Gk. monos, alone ; embryon, foetus.] 
Producing a single embryo at a 
time (bot.}. 

monergic (moner'jik) a. [Gk. monos, 
alone ; energos, active.] Having 
one energid ; consisting of one 
nucleated cell (bot.}. 
^imonilicorn (monil'ikorn) a. [L. monile, 
necklace ; cornu, horn.] Having 
antennae with appearance of a 
^rtain of beads (zool.}. 

moniiiform (monil'iform) a. [L. 
monile, necklace ; forma, shape.] 
Constricted at regular intervals, 
giving the appearance of a chain 
of beads ; appl. the nucleus of 
certain Infusoria (zool.} ; with con- 
tractions and expansions alternately, 
as the branches of certain roots 

monimostylic (mon'imostflik) a. [Gk. 
monimos, fixed ; stylos, pillar.] 
Having the quadrate united to the 
squamosal, and sometimes to other 
bones, as in certain Reptiles ; cf. 
streptostylic (zool.}. 

monocardian (mon'b'kar'dian) a. [Gk. 
monos, alone ; kardia, heart.] 
Having one auricle and ventricle 

monocarp (mon'okarp) n. [Gk. monos, 
alone ; karpos, fruit.] A mono- 
carpic plant (bot.}. 




monocarpellary (mon'okarpeTar!) a. 
[Gk. monos, alone ; karpos, fruit.] 
Containing a single carpel (bot.). 

monocarpic (mon'okar'pik) a. [Gk. 
monos, alone ; karpos, fruit.] Dying 
after bearing fruit once (dot.). 

monocarpous (mon'okar'pus) a. [Gk. 
monos, alone ; karpos, fruit.] Hav- 
ing one ovary developed from the 
gynoecium (bot.). 

monocephalous (mon'okeTalus, -sef-) 
a. [Gk. monos, alone; kephale, head.] 
With one capitulum only (tot.). 

monocercous (mon'oser'kus) a. [Gk. 
monos, alone ; kerkos, tail.] With 
one flagellum, as certain Protozoa 

inonocerous (monos'grus) a. [Gk. 
monos, alone ; keras, horn.] Hav- 
ing only one horn (zool.). 

monochasium (mon'oka'zTum) n. [Gk. 
monos, alone ; chasis, division.] A 
cymose inflorescence with main 
axes producing only one branch 
each (tot.). 

monochlainydeous (mon'oklamld'eus) 
a. [Gk. monos, alone ; cftlamys, 
cloak.] Apetalous ; having calyx 
but no corolla (tot.). 

monociliated (mon'osll'iated) a. [Gk. 
monos, alone ; L. ciliutn, lash.] 
Having one flagellum (zool.). ( W 

monoclinous (mou'okll'nus) a. [Ok. 
monos, alone ; aline, couch.] 
ing both stamens and pistiUi 
flower (tot.). 

monocotyledonous (monokot'ile'- 
donus) a. [Gk. monos, alone ; 
kotyledon, a cup-shaped hollow.] 
Having one cotyledon or embryo- 
lobe (tot.). 

monocrepid (mon'okrSp'id) a. [Gk. 
monos, alone ; krepis, foundation.] 
Appl. a desma formed by secondary 
silica deposits on a monaxial spicule 

monocule (mon'okul) . [Gk. monos, 
alone ; L. oculus, eye.] A one- 
eyed animal, as certain Insects and 
Crustacea (zool.). 

monocyclic (mSn'osik'lik) a. [Gk. 
monos, alone ; kyklos, circle.] 
Having one whorl or circular 
structure (biol.). 

monodactylous (mon'odak'tllus) a. 
[Gk. monos, alone ; daktylos, finger.] 
With one digit only (zool.). 

monodelphous, monadelphous. 

monodont (mon'6'dont) a. [Gk. monos, 
alone ; odous, tooth.] Having one 
persistent tooth ; appl. the narwal 
with one tusk ten or twelve feet 
long (zool.). 

monoecious (mone'shus) a. [Gk. 
monos, single ; oikos, house.] With 
male and female flowers on the 
same plant ; with sex organs on 
one gametophyte (tot.) ; hermaph- 
rodite (zool.). 

monogamous (monog'amus) a. [Gk. 
monos, single ; gamos, marriage.] 
Consorting with one mate only 

monoganglionic (mon'ogang'glionik) 
a. [Gk. monos, alone ; gangglion, 
a little tumour.] Having a single 
ganglion (zool.). 

monogastric (mon'ogas'trik) a. [Gk. 
monos, single ; gaster, stomach.] 
With only one gastric cavity 

monogenesis (mon'qjen'esis) n. [Gk. 
monos, alone ; genesis, descent.] 
Asexual reproduction ; the theory 
of the development of all organisms 
from a>^ingle cell (biol.). 

itic (m&n'ojenet'ik) a. [Gk. 
*nos, a\m&\\^genests, descent.] 
asexually ; direct, as 
, reproduction (biol.). 
, monogenetic. 

monogenous (monoj'finus) a. [Gk. 
monos, alone ; genos, offspring.] 
Asexual, as appl. reproduction 

monogonoporous (m6n'6g6n5p'6rus) 
a. [Gk. monos, alone ; gonos, off- 
spring ; poros, channel.] Having 
one genital pore common to both 
male and female organs, as in 
certain Turbellarians (zool.). 

monogony (monog'oni) n. [Gk. 
monos, alone ; gonos, offspring.] 
Non-sexual schizogony ; asexual 
reproduction (biol.). 

monogynoecial (mSn'ojme'shlal) a. 
[Gk. monos, alone ; gyne, female ; 
oikos, house.] Developing from one 
pistil (tot.). 

monogynous (monqj'inus) a. [Gk. 
monos, alone ; gyne, female.] Hav- 
ing one pistil only (tot.) ; consort- 
ing with one female mate, of male 
animals (zool.). 




monohybrid (mon'ohl'brid) n. [Gk. 
monos, alone ; L. hybrida, mongrel] 
A hybrid offspring of parents differ- 
ing in one character (biol.). 

monokaryon (mon'okar'Ion) n. [Gk. 
monos, alone; karyon, nut.] A nu- 
cleus with a single centriole (cyt.). 

monolophous (mon'olof'us) a. [Gk. 
monos, alone ; lophos, crest.] Appl. 
spicules with one ray forked or 
branched like a crest (zool.). 

monomastigate, monomastigote. 

monomastigote (mon'omas'tlgot) a. 
[Gk. monos, alone ; mastis, whip.] 
Having a single flagellum, as 
certain Protozoa (zool.). 

monomeniscous (mon'omems'kus) a. 
[Gk. monos, alone ; meniskos, a 
small moon.] Having an eye 
with only one lens (zool.). 

monomeric (mon'omer'ik) a. [Gk. 
monos, alone ; meros, part.] Pert. 
one segment ; derived from one 
part (biol.). 

atus) a. [Gk. monos, alone ; meros, 
part ; soma, body.] Having body- 
segments all fused together, as in 
certain Insects (zool.). 

monomerous (monom'erus) a. [Gk. 
monos, alone ; meros, part.] Con- 
sisting of one part only ; appl. 
flower-whorls (hot.). 

monomial (mono'mlal) a. [Gk. monos, 
alone ; L. notnen, name.] Appl. a 
name or designation consisting of 
one term only ; cf. binomial 

monomorphic (mon'omor'fik) a. 
[Gk. monos, alone ; morphe, form.] 
Developing with no or very slight 
change of form from stage to stage, 
as in certain Protozoa and Insects ; 
cf. polymorphic (zool.) ; producing 
spores of one kind only (hot.). 

monont (mon'ont) n, [Gk. monos, 
alone.] A single individual repro- 
ducing without conjugation, as opp. 
sporont or zygote (zool.). 

mononuclear (mon'onu'klear) a. [Gk. 
monos, alone ; L. nucleus, kernel.] 
With one nucleus only (biol). 

mononychous (mon'onflc'us) a. [Gk. 
monos, alone ; onyx, claw.] Having 
a single claw (zool.). 

monopetalous (mon'opeYalus) a. [Gk. 
monos, alone; petalon, petal.] Hav- 

ing one petal only ; having petals 
united all round (hot.). 

monophagous (monof'agus) a. [Gk. 
monos, alone ; phagein, to eat.] 
Subsisting on one kind of food ; 
appl. Sporozoa living permanently 
in a single cell (zool?). 

monophyletic (mon'ofilet'ik) a. [Gk. 
monos, alone ; phyle, tribe.] Derived 
from a single common parent form 

monophyllous (mon'ofil'us) a. [Gk. 
monos, alone ; phyllon, leaf.] Hav- 
ing one leaf only ; unifoliate ; 
having a one-piece calyx (dot.). 

monophyodont (mon'dfl'odont) a. 
[Gk. monos, alone ; phyein, to 
produce ; odous, tooth.] Having 
only one set of teeth, the milk 
dentition being absorbed in foetal 
life or absent altogether (zool.). 

monoplacid (mon'oplas'id) a. [Gk. 
monos, alone ; plakous, a flat cake.] 
With one plate only, of any par- 
ticular kind (biol.). 

monoplacula (mon'oplak'ula) n. [Gk. 
monos, alone ; plax, a flat plate.] 
A single-layered placula (biol.). 

monoplastic (mon'oplas'tik) a. [Gk. 
monos, alone ; plastos, formed.] 
Persisting in one form (biol.). 

monopodial (mon'opo'dlal) a. [Gk. 
monos, alone ;pous, foot.] Branch- 
ing from one main or primary axis 
acropetally (bot.). 

monopodium (mon'opo'dlum) n. [Gk. 
monos, alone ;pous, foot.] A single 
main or primary axis from which 
all main lateral branches develop, 
as in the pine (bot.). 

monopyrenous (mon'opfre'nus) a. 
[Gk. monos, alone ; pyren, kernel.] 
Single-stoned, as a fruit (bot.). 

monorhinal (mon'ori'nal) a. [Gk. 
monos, alone ; rhis, nose.] Having 
only one nostril, as the Cyclostomes 

monosepalous (mon'osep'alus) a. [Gk. 
monos, alone ; sepalon, sepal.] Hav- 
ing a single sepal ; having all sepals 
united into one (bot.). 

monosiphonic (mon'b'sifon'ik) a. [Gk. 
monos, alone ; siphon, a small pipe.] 
Having the tubes of a hydrocaulus 
distinct from one another, as in 
certain Hydromedusae (zool.). 

monosiphonous (mon'osl'fonus) a. 




[Gk. monos, alone ; siphon, a small 
pipe.] Having a single central 
tube in the filament, as in certain 
red Algae (bot.}. 

monospermous (mon'ospeYmus) a. 
[Gk. monos, alone ; sperina, seed.] 
One-seeded (bot.}. 

monospermy (mon'ospeYml) n. 
[Gk. monos, alone ; sperma, seed.] 
Normal fertilization by the entrance 
of one sperm only into an ovum 

monospondylic (mon'ospondil'ik) a. 
[Gk. monos, alone ; sphondylos, a 
vertebra.] Appl. vertebrae without 
intercentra (zool.}. 

monosporangium (mon'dsporan'jTum) 
n. [Gk. monos, alone ; sporos, seed ; 
anggeion, vessel.] A sporangium 
producing simple spores (bot.}. 

monospore (mon'ospor) n. [Gk. monos, 
alone ; sporos, seed.] A simple or 
undivided spore (bot.}. 

monosporous (monos'porus) a. [Gk. 
monos, alone ; sporos, seed.] Having 
only one spore or a simple spore 

monostachyous (mon'ostak'ms) a. 
[Gk. monos, alone ; stachys, a corn- 
ear.] With only one spike (bot.}. 

monostele (mon'ostel) n. [Gk. monos, 
alone ; stele, column.] An axis 
stele when only one is the direct 
continuation of the plerome (bot.}. 

monostelic (mon'osteTik) a. [Gk. 
monos, alone ; stele, column.] Hav- 
ing a single stele or central cylinder 
running through the whole axis 

monostichous (monos'tikus) a. 
[Gk. monos, alone ; stichos, row.] 
Arranged in one row (zool.} ; along 
one side of an axis (bot.}. 

monostigmatous (mon'ostig'matus) a. 
[Gk. monos, alone ; stigma, mark.] 
With one stigma only (bot.}. 

monostylous (mon'osti'lus) a. [Gk. 
monos, alone ; stylos, pillar.] Having 
one style only (bot.}. 

monosy (mon'osl) n. [Gk. monos, 
alone.] The separation of parts 
normally fused (biol.}. 

monosymmetrical (mon'osTmet'rikal) 
a. [Gk. monos, alone ; syn, with ; 
metron, measure.] Having only 
one plane of bilateral symmetry 

monothalamic (mon'othal'amik) a. 
[Gk. manes, alone ; thalamos, 
chamber.] Appl. fruits formed 
from single flowers ; having one 
gynoecium (dot.}. 

monothalamous (mon'otharamus) a. 
[Gk. monos, alone ; thalamos, 
chamber.] Unilocular ; single - 
chambered ; appl. shells of Fora- 
minifers and other Protozoa (zool.}. 

monothecal (mon'othe'kal) a. [Gk. 
monos, alone ; theke, box.] Having 
one loculus ; single - chambered 

monothelious (mon'othe'llus) a. [Gk. 
monos, alone ; thelys, female.] 
Appl. a female consorting with 
more than one male (biol.}. 

monotocous (monot'oktis) a. [Gk. 
monos, alone ; tokos, offspring.] 
Having one at a birth (biol.}. 

monotrochous (monot'rokus) a. [Gk. 
monos, alone ; trochos, wheel.] 
Having a single-piece trochanter, 
as in most stinging Hymenoptera 

monotrophic (mon'otrof'ik) a. [Gk. 
monos, alone ; trophe, nourishment.] 
Subsisting on one kind of food 

monotype (mon'otlp) n. [Gk. monos, 
alone ; L. typus, type.] A single 
type which constitutes a species or 
genus (biol.}. 

monozoic (mon'ozo'ik) a. [Gk. monos, 
alone ; zoon, animal.] Appl. archi- 
spores forming only one sporozoite 
on liberation from the cyst ; pro- 
ducing one sporozoite only (biol.}. 

monticolous (montik'olus) a. [L. 
mons, mountain ; colere, to inhabit.] 
Inhabiting mountainous regions 

morphalaxls (mor'falak'sls) n. [Gk. 
morphe, form ; L. laxare, to release.] 
Transformation of one part directly 
into another, in regeneration of 
parts (zool.}. 

morphology (morfol'qji) n. [Gk. 
morphe, form ; logos, discourse.] 
The science of the form and struc- 
ture of plants or animals, as dis- 
tinct from consideration of the 

morphon (mor'fon) n. [Gk. morphe, 
form.] A definitely formed indi- 
vidual, as opp. a bion (biol.}. 




morphosis (m6r'fos!s, morfo'sis) n. 
[Gk. morphosis, a forming.] The 
manner of development of part or 
organism (biol.}. 

morphotic (morfot'ik) a. [Gk. mor- 
phosis, a forming.] Tissue-building 

morula (mor'ula) n. [L. morum, a 
mulberry.] A solid cellular globu- 
lar mass, the first result of ovum 
segmentation ; the stage in de- 
velopment preceding the gastrula 
stage (emb.}. 

morulation (morula'shun) n. [L. 
morum, a mulberry.] Morula- 
formation by segmentation (emb.}. 

morulit (mor'ulit) n. [L. morum, a 
mulberry.] Nucleolus or kary- 
osome (cyt.}. 

motor (mo'tor) a. [L. movere, to 
move.] Pert, or connected with 
movement ; appl. nerves (anat., 

motor areas, areas of the brain 
where motion is supposed to be 
correlated (phys.}. 

motor end-plates, the terminal ex- 
pansions of nerves in muscle fibres 

motor neurons, nerve cells with 
appendages and branches, con- 
cerned in the regulation of move- 
ment (anat.}. 

motor ocull, the third cranial nerve 

motorium (moto'rium) n. [L. movere, 
to move.] Motor areas ; the part 
of the nervous system where the 
motorial sense is localized (phys.}. 

moult (molt)z/. [L. mutare,\.o change.] 
To cast or shed periodically the 
outer covering, whether of feathers, 
hair, skin, or horns (zool.}. 

mouth part, a head or mouth 
appendage of Arthropods or In- 
sects (zool.}. 

mucific (musif'ik) a. [L. mucus, 
mucus ; facere, to make.] Mucus- 
secreting (phys.}. 

muclform (musiform) a. [L. mucus, 
mucus ; forma, shape.] Resembling 
mucus (phys.}. 

mucigen (mu'sTjgn) n. [L. mucus, 
mucus ; Gk. genos, offspring.] The 
substance of certain granules in 
the cells of mucous membrane 

mucilage (mu'sllaj) n. [L. mucus, 
mucus.] A substance produced in 
cell-walls of certain plants due to 
changes in the cellulose or pectose 
constituents, causing exudations of 
gum when degeneration of the cell- 
wall is excessive (bot.}. 

mucilage cell, a cell which secretes 
mucilage (bot.}. 

mucilaginous (mii'silaj'inus) a. [L. 
mucus, mucus.] Pert, containing, 
resembling, or composed of muci- 
lage ; appl. certain glands of joints 
(anat.} ; appl. cells, ducts, canals, 
slits (boL\ 

mucin (mu'sln) n. [L. mucus, mucus.] 
A glucoproteid of mucus (phys.}. 

mucinogen (mustn'qjgn) n. [L. mucus, 
mucus ; Gk. genos, offspring.] A 
substance producing mucin by 
reaction of alkalies (phys.}. 

muciparous (musip'arus) a. [L. 
mucus, mucus ; parere, to beget.] 
Mucus-secreting (phys.}. 

mucocutaneous (mu'kokuta'neus) a. 
[L. mucus, mucus ; cutis, skin.] 
Pert, skin and mucous membrane 

mucodermal (mu'koder'mal) a. [L. 
mucus, mucus ; Gk. derma, skin.] 
Pert, skin and mucous membrane 

mucoid (mu'koid) a. [L. mucus, 
mucus ; Gk. eidos, like.] Pert, or 
caused by mucus or mucilage ; 
appl. degeneration (bot.} ; tissue 

mucosa (muko'sa) n. [L. mucus, 
mucus.] A mucous membrane 

mucoserous (mu'kose'rus) a. [L. 
mucus, mucus ; serum, whey.] 
Secreting mucus and body fluid 

mucous (mu'kus) a. [L. mucus, 
mucus.] Secreting, containing, or 
pert, mucus ; appl. glands, sheaths, 
tissue (anat}. 

mucro (mu'kro) n. [L. mucro, a sharp 
point.] A stiff or sharp point 
abruptly terminating an organ 

mucronate (mu'kronat) a. [L. mucro, 
a sharp point.] Abruptly termin- 
ated by a sharp spine ; mucro- 

mucronulate (mukron'ulat) a. [L. 




mucro, a sharp point.] Tipped with 
a small mucro. 

mucronule (mu'kronul) n. [L. mucro, 
a sharp point.] A small mucro. 

muculent (mu'kulnt) a. [L. mucus, 
mucus.] Mucoid ; containing 
mucus ; mucilaginous (hot.}. 

mucus (mu'kus) n. [L. mucus, mucus.] 
The slimy, glairy substance secreted 
by mucous membrane (phys.}. 

Mullerian (mule'rlan) a. [Joh. Muller, 
German anatomist, and other 
Miillers.] Appl. eminence, fibres 
(anat.} ; corpuscles (bot.} ; larva 

Miillerian ducts, ducts arising on 
the lateral aspects of the Wolffian 
ducts (emb.}. 

multangular (multSng'gular) a. [L. 
multus, many ; angulus, angle.] 
Appl. two carpal bones, the greater 
and lesser multangulum, respect- 
ively the trapezium and the trape- 
zoid (anat.}. 

multiarticulate (mul'tlartik'ulat) a. 
[L. multus, many ; articulus, joint.] 
With many articulations ; many- 
jointed (zoo/.). 

multicamerate (mul'tlkam'erat) a. 
[L. multus,many; camera, chamber.] 
Multilocular ; with many chambers. 

multlcapsular (mul'tikap'sular) a. [L. 
multus, many ; capsula, a little 
chest.] With many capsules (bot.}. 

multicarinate (mul'tikar'Inat) a. [L. 
multus, many ; carina, keel.] Hav- 
ing many keels. 

multicellular (murtiseTular) a. [L. 
multus, many ; cella, storeroom.] 
Many-celled ; consisting of more 
than one cell (biol.}. 

multlcentral (mul'tisSn'tral) a. [L. 
multus, many ; centrum, centre.] 
With more than one centre of 
growth or development (biol.}. 

multicipital (mul'tisip'ital) a. [L. 
multus, many ; caput, head.] With 
many heads or branches arising 
from one point (bot.}. 

multicostate (mul'tikos'tat) a. [L. 
multus, many ; costa, rib.] With 
many ribs or veins (bot.} ; with 
many ridges (zool.}. 

multicuspid (mul'tlkus'pld) a. [L. 
multtis, many ; cuspis, spear-head.] 
With several cusps or tubercles ; 
appl. molar teeth (anat.}. 

multidentate (mul'tidgn'tat) a. [L. 
multus, many ; dens, tooth.] With 
many teeth, or indentations (biol.}. 

multidigitate (mul'tldij'itat) a. [L. 
multus, many ; digitus^ finger.] 
Many-fingered (zool.}. 

multifid (mul'tifid) a. [L. multus, 
many ; fidus, cleft.] Having many 
clefts or divisions (dot.}. 

multiflagellate (mul'tlflaj'elat) a. [L. 
multus, many ; flagellum, whip.] 
Furnished with several or many 
flagella ; polymastigote (zool.}. 

multiflorous (mul'tiflo'rus) a. [L. 
multus, many ; flos, flower.] Bear- 
ing many flowers (hot.}. 

multifoliate (mul'tlfo'liat) a. [L. 
multus, many ; folium, leaf.] With 
many leaves (bot.\ 

multifoliolate (muf'tifo'liolat) a. [L. 
multus, many ; foliolum, a small 
leaf.] With many leaflets (bot.\ 

multiganglionate (mul'trgang'- 
glI6nat) a. [L. multus, many ; 
[Gk. gangglion, a small tumour.] 
With several or many ganglia 

multigyrate (mul'tijl'rat) a. [L. 
multus, many ; gyrus, circle.] 
With many gyri ; tortuous (biol.}. 

multljugate (mul'tijoog'at) a. [L. 
multus, many ; jugum, yoke.] 
Having many pairs of leaflets 

multilamlnate (mul'tTlam'inat) a. 
[L. multus, many ; lamina, plate.] 
Composed of several or many 
laminae (biol.}. 

multilobate (mul'tilo'bat) a. [L. 
multus, many ; lobus, lobe.] Com- 
posed of many lobes. 

multilobulate (mul'tllob'ulat) a. [L. 
multus, many ; lobulus, a small 
lobe.] Having many lobules. 

multilocular (mul'tilok'ular) a. [L. 
multus, many ; loculus, chamber.] 
Having many cells or chambers. 

multinervate (mul'tlneYvat) a. [L. 
multus, many ; nervus, sinew.] 
With many nerves or nervures 

multinodal (mul'tlno'dal) a. \L. 
multus, many ; nodus, knot.] With 
many nodes (bot.}. 

multinomial (mul'tlno'inlal) a. [L. 
multus, many ; nomen, name.] 
Appl. a name or designation com- 




posed of several names or terms ; 
cf. binomial (biol.}. 

multinucleate (mul'tlnu'kleat) a. [L. 

multus, many ; nucleus, kernel.] 

With several or many nuclei (cyt.}. 

xnultinucleolate (mul'ttnu'kleolat) a. 

[L. multus, many ; nucleolus, a 

small kernel.] With more than 

one nucleolus (cyt.}. 

multiovulate (mul'tlo'vulat) a. [L. 

multus, many ; ovum, egg.] With 

several or many ovules (hot.*). 

multiparous (multip'arus) a. [L. 

multus, many ; parere, to beget.] 

Bearing several, or more than 

one, at a birth (zool.} ; developing 

several or many lateral axes (hot.}. 

multiple corolla, a corolla with two 

or more whorls of petals (bot,\ 
multiple fission, repeated division ; 
division into a large number of 
parts or spores (biol.}, 
multipolar (mul'tipo'lar) a. [L. 
multus, many ; polus, an axis- 
end.] Appl. nerve-cells with 
many dendrites or branching pro- 
cesses (anat.}. 

multiradiate (mul'tira'dlat) a. [L. 
multus, many; radius, ray.] Many- 

multiramose (mul'tirarn'os) a. [L. 
multus, many ; ramus, branch.] 
Much branched. 

multiseptate (mul'tise'p'tat) a. [L. 
multus, many ; septum, partition.] 
Having numerous septa or par- 

multiserial (miU'tise'rial) a. [L. 
multus, many ; series, row.] 
Arranged in several or many 

multispiral (mul'tispl'ral) a. [L. 
multus, many ; spira, coil.] With 
many coils or whorls, 
multistaminate (mul'tTstam'inat) a. 
[L. multus, many ; stamen, some- 
thing standing.] Having several 
or many stamens (bot,\ 
multisulcate (mul'tisurkat) a. [L. 
multus, many ; sulcus, furrow.] 
Much furrowed. 

multitentaculate (mul'tltentak'ulat) 
a. [L. multus, many ; tentaculum, 
feeler.] Having many tentacles 

multituberculate (mul'tTtubeYkulat) 
a. [L. multus, many ; tuberculum^ 

a small hump.] Having several 
or many tubercles or small prom- 

multituberculy (mul'titubeVkuli) n. 
[L. multus, many ; tuberculum, a 
small hump.] The theory that 
molar teeth are derived from 
forms with a number of tubercles 

multivalve (mul'tivalv) n. [L. multus, 
many ; valvae, folding-doors.] A 
shell composed of more valves or 
pieces than two (zool.~). 

multivincular (mul'tiving'kular) a. 
[L. multus, many ; vinculum, 
chain.] Appl. the hinge of bi- 
valve shells when it has several 
ligaments (zool,}. 

multivoltine (mul'tTvortTn) a. [L. 
multus, many ; It. volta, turn.] 
Having more than one brood in 
a year ; appl. silkworms (zool.), 

multocular (multok'ular) a. [L. 
multus, many ; oculus, eye.] 

multungulate (multung'gulat) a. 
[L. multus, many; unguis, hoof.] 
Having the hoof in more than 
two parts (zool.}. 

muricate (mu'rikat) a. [L. muricatus, 
full of sharp points.] Formed with 
sharp points ; covered with short 
sharp prickles (bwl.}. 

muriform (mu'riform) a. [L. murus, 
wall ; forma, shape.] Like a brick 
wall; appl. a variety of parenchyma 
so arranged, occurring in medullary 
rays of Dicotyledons and in corky 
formations (bot.}. 

muscicoline (muslk'olin) a. [L. 
muscus, moss ; colere, to inhabit.] 
Livin or growing among mosses 

muscicolous, muscicoline. 

muscle (mus'l) n. [L. musculus, 
muscle.] A mass of contractile 
fibres with motorial function ; the 
fleshy part of the body, composed of 
muscular tissue (phys.}. 

muscle-banners, folds or plaits of 
mesogloea on the sulcar aspects of 
Anthozoan mesenteries, supporting 
the retractor muscles (zool.}. 

muscoid (mus'koid) a. [L. muscus, 
moss ; Gk. eidos, resemblance.] 

muscous, muscoid, 




muscular (mus'kulXr) a. [L. musculus, 
muscle.] Pert, or consisting of 
muscle ; appl. sense, excitability 
(phys.}, stomach (zool.\ fibres, 
process,' tissue, triangle (anat.}. 

musculature (miis'kulatur) n. [L. 
musculns, muscle.] The system or 
arrangement of muscles as a whole 

musculocutaneous (mus'kulokuta'- 
neus) a. [L. musculus, muscle ; 
cutis, skin.] Pert, muscles and 
skin ; appl. veins and nerves of leg 
and arm supplying muscles and skin 
(ana/., zooL). 

musculophrenic (mus'kulofre'n'ik) a. 
[L. musculus, muscle ; Gk. phren, 
midriff.] Supplying diaphragm and 
body-wall muscles ; appl. an artery 

musculospiral (mus'kulospl'ral) a. 
[L. musculus, muscle ; spira, coil.] 
Appl. a nerve which passes spirally 
down the humerus (anat.}. 

mutation (muta'shun) n. [L. mutare, 
to change.] Gradual variation 
towards a definite change of struc- 
ture ; discontinuous variation ; the 
theory of De yries that new fonns, 
differing sufficiently to constitute a 
new variety, arise spontaneously 
and remain true (biol.}. 

mutlcous (mu'tikus) a. [L. muticus, 
maimed.] Without defensive struc- 
tures, as clawless, toothless, blunt 

mutilation (mu'tilashun) n. [L. ntu- 
tilare, to maim.] Loss of an 
essential part of a structure ; am- 
putation (zool.}. 

mutualism (mu'tualizm) n. [L. 
mutuus, exchanged.] A form of 
symbiosis in which both parties 
derive advantage without sustain- 
ing injury (biol.}. 

myarian (mla'rian) a. [Gk. mys, 
muscle.] Appl. classification ac- 
cording to musculature (biol.}. 

mycele, mycelium. 

mycelioid (mlse'lloid) a. [Gk. mykes, 
mushroom ; eidos, resemblance.] 
Like mycelium. 

mycelium (mlse'Iium) n. [Gk. mykes, 
fungus.] The network of filament- 
ous cells forming the typical vege- 
tative structure of Fungi (hot.}. 

mycetogenetlc (mlse'toje'ne't'lk) a. 

[Gk. mykes, fungus ; genesis, de- 
scent.] Produced by a Fungus. 

mycetogenic, mycetogenetic. 

mycetoid (mlse'toid) a. [Gk. mykes, 
fungus ; eidos, resemblance.] Fun- 
goid ; fungus-like. 

mycetology, mycology. 

mycetophagous (mfsetSfagus) a. 
[Gk. mykes, fungus ; phagein, to 
eat.] Fungivorous ; feeding on 
Fungi (zool.}. 

mycoderm (mfkodfirm) n. [Gk. 
mykes, fungus ; derma, skin.] A 
bacterium of alcoholic fermentation. 

mycology (mlkol'qjl) n. [Gk. mykes, 
fungus ; logos, discourse.] The 
department of botany dealing with 

mycoplasm (mfkoplSzm) n. [Gk. 
mykes, fungus ; plasma, form.] A 
parasitic substance of cereal seeds 
which may give rise to a rust 
Fungus (bot.}. 

mycorhiza (miTcorfza) n. [Gk. mykes, 
fungus ; rhiza, root.] Association 
of a fungus with the roots of a 
higher plant, with mutual benefit 

n. [Gk. myelos, marrow ; en, in ; 
kephale, head.] The posterior part 
of the hind-brain (emb.) ; the 
medulla oblongata ; brain and 
spinal cord generally (anat.). 

my elm (ml'e'lin) n. [Gk. myelos, 
marrow.] A highly refracting fatty 
material forming the medullary 
sheath of nerve fibres (anat.}. 

myelination (mr'SUna'shun) n. [Gk. 
myelos, marrow.] Acquisition of a 
medullary sheath (anat.}. 

myelinization, myelination. 

myelocoel (ml'e'ldsel) n. [Gk. myelos, 
marrow ; koilos, hollow.] The 
spinal cord canal (anat.}. 

myelocyte (mfgloslt) n. fGk. myelos, 
marrow ; kytos, hollow.] An amoe- 
boid marrow cell, resembling a 
lymphoid corpuscle (anat.}. 

myeloid (mfe'loid) a. [Gk. myelos, 
marrow ; eidos, resemblance.] Like 
marrow in appearance or structure 

myelon (ml'e'lbn) n. [Gk. myelos, 
marrow.] The spinal cord of 
vetebrates (zool.}. 
myeloplast (ml'gloplast) n. [Gk. 




myelos, marrow ; plastos, formed.] 
A leucocyte of bone marrow. 

myeloplax (ml'eloplaks) n. [Gk. 
myelos, marrow ; plax, something 
flat.] A giant-cell of marrow and 
blood-forming organs, sometimes 
multinucleate, but in most cases 
multinucleolate (anat.}. 

mylohyoid (ml'lohl'oid) a. [Gk. myle, 
mill ; hyoeides, Y-shaped.] In the 
region of hyoid bone and posterior 
part of mandible ; appl. artery, 
groove, muscle, nerve (anat.}. 

myoalbumin (ml'oalbu'min) n. [Gk. 
mys, muscle ; L. albumen, white of 
egg.] An albumin product of 
muscle (phys.}. 

myoblast (ml'oblast) n. [Gk. mys, 
muscle; blastos, bud.] A cell which 
develops into muscle fibre (smb.}. 

myocardium (mi'6'kar'dium) n. [Gk. 
mys, muscle ; kardia, heart.] The 
muscular walls of the heart (anat.}. 

myochrome (ml'b'krom) n. [Gk. mys, 
muscle ; chroma, colour.] A muscle- 

myocoel (ml'osel) n. [Gk. mys, muscle ; 
koilos, hollow.] Part of the coelom 
enclosed in a myotome (emb.}. 

myocomxna (ml'okom'a) n. [Gk. mys, 
muscle ; komma, a clause.] A 
myoseptum or ligamentous connec- 
tion between successive myotomes 

myocyte (mi'oslt) n. [Gk. mys, 
muscle; kytos, hollow.] A contrac- 
tile layer of ectoplasm of Gregar- 
ines ; a contractile cell (zool.}. 

myodome (mfodom) n. [Gk. mys, 
muscle ; L. domus, house.] A 
chamber containing the eye-muscles 
in some Teleosts (zool.}. 

myodynamic (ml'odinam'ik) a. [Gk. 
mys, muscle ; dynamis, power.] 
Pert, muscular force or contraction 

myoepicardial (mi'oe'pikar'dial) a. 
[Gk. mys, muscle ; epi, upon ; 
kardia, heart.] Appl. a mantle, 
consisting of the mesocardium 
walls, destined to form the muscu- 
lar and epicardial walls of the 
heart (emb.}. 

myoepithelial (ml'oepithe'lial) a. [Gk. 
mys, muscle ; epi, upon ; thele, 
nipple.] Pert, muscle and epi- 
thelium (anat.} ; appl. epithelium 

cells with contractile outgrowths, 
as in Coelenterates (zool.}. 

myoflbrillae (ml'of Ibril'e) n. plu. [Gk. 
mys, muscle ; L. fibrilla, a small 
fibre.] Contractile fibrils of muscu- 
lar tissue (anat.}. 

myoglobulin (ml'oglob'ulin) n. [Gk. 
mys, muscle ; L. globulus, a small 
globe.] A globulin of muscle (phys.}. 

myohaematin (ml'ohe'matm) n. [Gk. 
mys, muscle ; haima, blood.] A 
pigment of muscular tissue (phys.}. 

myoid (ml'oid) a. [Gk. mys, muscle ; 
eidos, resemblance.] Resembling or 
composed of muscular fibres (anat.}. 

myolemma (mi'blem'a) n. [Gk. mys, 
muscle ; lemma, skin.] The sheath 
of muscle fibre ; sarcolemma. 

myology (mlol'oji) n. [Gk. mys, 
muscle ; logos, discourse.] The 
department of anatomy dealing 
with muscles. 

myomere (mi'omer) n. [Gk. mys, 
muscle ; meros, part.] A muscle- 
segment of Arthropods, divided off 
by connective tissue insertions ; 
a myocomma (zool.}. 

myoneme (ml'bnem) n. [Gk. mys, 
muscle ; nema, thread.] A minute 
contractile fibril of Protozoa (zool.}. 

myoneure (mi'onur) n. [Gk. mys, 
muscle ; neuron, nerve.] A motorial 
nerve-cell (phys.}. 

myonicity (mi'dnis'iti) n. [Gk. mys, 
muscle.] The contracting power 
of muscular tissue (phys.}. 

myophan (ml'bfan) n. [Gk. mys, 
muscle ; pkainein, to appear.] The 
contractile layer of Protozoa (zool.}. 

myophore (ml'of or) n. [Gk. mys, 
muscle ; pherein, to bear.] A struc- 
ture adapted for muscle attachment 

myophrisk (ml'ofrisk) n. [Gk. mys, 
muscle ; phrix, ripple.] A myo- 
neme or contractile element of 
Protozoa (zool.}. 

myopolar (ml'bpo'lar) a. [Gk. mys, 
muscle ; polos, an axle-end.] Pert. 
muscular polarity (phys.}. 

myoproteid (mi'opro'teid) n. [Gk. 
mys, muscle ; protos, first.] A 
globulin - like substance of fish 
muscle (phys.}. 

myoseptum (ml'osep'tum) n. [Gk. 
mys, muscle ; L. septum, partition.] 
A myocomma, which see, 




myosin (mfosin) n. [Gk. mys, muscle.] 
A globulin of dead muscular tissue 

myotasis (mlot'asis) n. [Gk. mys, 
muscle ; fast's, tension.] Muscular 
tension or tonicity (phys.~). 

myotome (mi'otom) n. [Gk. mys, 
muscle ; fame, a cutting.] One of 
a series of hollow cubes formed in 
the early vertebrate embryo (emb.) ; 
a muscular metamere of primitive 
vertebrates and segmented inverte- 
brates (zoo/.). 

myotonia (mloto'ma) n. [Gk. mys, 
muscle ; tonos, tension.] Muscular 
tension or tonicity (pkys.\ 

myrmecophagous (mirmSkof'agus) a. 
[Gk. myrmex, ant ; phagein, to 
eat.] Ant-eating (zoo/.). 

myrmecophile (mir'mSkofil) n. [Gk. 
myrmex, ant ; philos, loving.] A 
guest insect in a nest of ants 

mynnecophyte (mir'mgkoflt) n. [Gk. 
myrmex, ant ; phyton, plant.] A 
myrmecophilous plant, or one that 
benefits from ant inhabitants and 
has special adaptations for housing 
them (bot.). 

myrosin (mir'osin) n. [Gk. myron, 
unguent.] An enzyme of mustard 
seeds, acting upon glucosides (bot.). 

myxamoeba (mik'same'ba) n. [Gk. 
myxa, slime ; amoibe, change.] A 
mycetozoan spore in the amoebula 
stage (zoo/.). 

myxoflagellate (mik'soflaj'glat) n. 
[Gk. myxa, slime ; L. flagellum, 
whip.] A flagellula or zoospore, 
the stage in mycetozoan develop- 
ment following the myxamoeba, and 
which multiplies by fission (zoo/.). 

myxopodium (mik'sopo'dlum) n. [Gk. 
myxa, slime ; pous, foot.] A slimy 
pseudopodium (zoo/.). 

myxopterygium, mixipterygium. 


nacreous (naTcreus) a. [Ar. nakir, 

hollowed.] Yielding or resembling 

mother-of-pearl (zoo/.). 
nacrine (na'krin) n. [Ar. nakir, 

hollowed.] Mother-of-pearl colour 


naevose (na'vos, ne'vos) a. [L. naevus, 
spot.] Freckled ; spotted with con- 
genital marks (zoo/.). 

nail (nal) n. [A.S. naegel, nail.] The 
terminal horny plate of finger or 
toe (zoo/.). 

nail bone, the terminal bone of finger 
or toe. 

nanism (nan'izm) n. [Gk. nanos, 
dwarf.] Dwarfishness. 

nanoplankton (nan'6'plang'ktSn) 
n. [Gk. nanos, dwarf; plang- 
ktos, wandering.] Microscopic 

napiform (na'piform) a. [L. napus, 
turnip ; forma, shape.] Turnip- 
shaped ; appl. roots (bot.). 

narcotic (narkfit'ik) n. [Gk. narke, 
numbness.] A drug which pro- 
duces unconsciousness (zoo/.). 

nares (na'rez, na'rgz) n. plu. [L. 
nares, nostrils.] Nostrils (zoo/.). 

nares, anterior, the openings of 
the olfactory organ to the exterior 

nares, posterior, the openings of the 
olfactory organ into the pharynx or 
throat (zoo/.). 

narial (na'rial) a. [L. nares, nostrils.] 
Pert, the nostrils (zoo/.). 

narial septum, the partition between 
the nostrils (zoo/.). 

naricorn (nar'ik6rn) n. [L. nares, 
nostrils ; cornu, horn.] The ter- 
minal horny part of nostril of 
Turbinares (zoo/.) ; nasal scale 

nariform (narTform) a. [L. nares, 
nostrils ; forma, shape.] Shaped 
like nostrils (zoo/.). 

nasal (na'zal) a. [L. nasus, nose.] 
Pert, the nose (zoo/.). 

nasion (na'zton) n. [L. nasus, nose.] 
The middle of the nasofrontal 
suture (anat.). 

Nasmyth's membrane, a trans- 
parent sheet of membrane over 
the enamel of the crown of a 
mammalian tooth (phys.). 

nasoantral (na'zoan'tral) a. [L. nasus, 
nose ; antrum, cavity.] Pert, nose 
and maxillary cavity (anaf.). 

nasobuccal (na'zobuk'al) a. [L. nasus, 
nose ; bucca, cheek.] Pert, nose 
and cheek (anaf.) ; pert, nose and 
mouth cavity (zoo/.). 

nasociliary (na'zosTltarl) a. [L. nasus, 




nose ; cilia, eyelashes.] Appl. nasal 
nerve off which the ciliary nerves 
branch (anat.). 

nasofrontal (na'zofrun'tal) a. [L. 
nasus, nose ; frons, forehead.] 
AppL part of the superior oph- 
thalmic vein in nose and forehead 
region (anat.). 

nasolabial (na'zola'bial) a. [L. nasus, 
nose ; labium, lip.] Pert, nose and 
lip ; appl. muscle (anat.). 
nasolacrimal (na'zolak'rimal) a. [L. 
nasus, nose ; lacrima, tear.] Appl. 
a duct from the lacrimal sac to the 
meatus of the nose (anat.). 
nasomaxillary (na'zomaksTrari) a. 
[L. nasus, nose ; mairilla, jaw.] 
Pert, nose and jaw (anat.). 
nasooptic (na'zoop'tlk) a. [L. nasus, 
nose ; Gk. optikos, relating to sight.] 
Appl. a furrow, an embryonic groove 
between nasal and maxillary pro- 
cesses (smb.). 

nasopalatal (na'zopal'atal) a. [L. 
nasus, nose ; palatus, palate.] 
Appl. a canal between the nose 
and palate (anat.). 

nasopalatine (na'zopal'atin) a. [L. 
nasus, nose ; palatus, palate.] Pert. 
nose and palate (anat.). 

nasopharyngeal (na'zofarin'jeal) a. 
[L. nasus, nose ; Gk. pharyngx, 
gullet.] Pert, the nose and 
pharynx (anat.). 

nasopharynx (na'zofar'mgks) n. [L. 
nasus, nose ; Gk. pharyngx, gullet.] 
That part of pharynx continuous 
with posterior nares (anat.). 

nasoturbinal (na'zotur'binal) a. [L. 
nasus, nose ; turbo, wheel.] Appl. 
outgrowths from the lateral wall of 
the nasal cavity increasing the area 
of sensory surface (zool.). 

nasus (na'zus) n. [L. nasus, nose.] 
The nose ; the clypeus of an in- 
sect's head (zool.). 

natal (na'tal) a [L. nates, buttocks.] 
Connected with the buttocks 

natant (na'tant) a. [L. natare, to 
swim.] Floating on the surface of 
water (zool., bot.). 

natatorial (na'tato'rial) a. [L. natare, 
to swim.] Formed or adapted for 
swimming (zool.). 

natatory (na'tatorl) a. See natatorial 

nates' (na'tfcz) n. plu. [L. nates, but- 

tocks.] Buttocks (anat.) ; umbones 

native (na'tiv) a. [L. gnatus, born.] 
Appl. animals and plants which 
originated in the district or area 
in which they live, not those im- 
ported thereinto (biol.). 

natural selection, the processes 
occurring in nature resulting in 
the survival of the fittest and the 
elimination of the individuals less 
adapted to their surroundings (biol.). 

nauplius (no'plius) n. [L. nauplius, 
a shell-fish.] The earliest larval 
stage of entomostracan Crustaceans 

nautillform (notil'iform) a. [L. 
nautilus, nautilus ; forma, shape.] 
Shaped like a nautilus shell (zool.). 

navel (na'vgl) n. [A.S. nafele, navel.] 
Place of attachment of the um- 
bilical cord (emb.). 

navicular (navik'ular) a. [L. navis, 
ship.] Boat-shaped. 

naviculare (navlk'ulare) n. [L. navis, 
ship.] The scaphoid radiale of the 
mammalian carpus (anat.). 

nebenkern (na'bgnkgrn) n. [Ger. 
neben, near ; kern, kernel.] An 
extra-nuclear chromatinic body in 
the spermatia (cyt.). 

nebenk8rper (na'benker'pSr) n. [Ger. 
neben, near ; korper, body.] A body 
surrounded by oil-drops at the 
hinder pole of Pyrodinium, perhaps 
the seat of luminosity (zool.). 

necrogenous (nekroj'eniis) a. [Gk. 
nekros, dead ; genos, offspring.] 
Living or developing in dead bodies 

necrophagous (nSkrof'agus) a. [Gk. 
nekros, dead ; phagein, to eat.] 
Feeding on dead bodies (zool.). 

necrophilous (nekrof'Ilus) a. [Gk. 
nekros, dead ; philein, to love.] 
Feeding on dead bodies (zool.). 

nectar (ngk'tar) n. [G\a.nektar, nectar.] 
The sweet substance secreted by 
special glands, the nectaries, in 
flowers (bot.). 
nectar gland, see nectary. 

nectar guides, the series of markings 
on the petals of flowers, pointing 
apparently to the easiest way to 
reach the nectar, and at the same 
time ensuring that the insect visitor 
will cause cross-fertilization (biol.). 




nectarlferous (nek'tarif'grus) a. [Gk. 
nektar, nectar ; L. ferre, to carry.] 
Producing or having nectar-secret- 
ing structures (hot.}. 

nectarivorous (nek'tariv'orus) a. [Gk. 
nektar, nectar ; L. vorare, to de- 
vour.] Nectar-sipping ; appl. to 
certain Insects (zoo/.). 

nectary (ngk'tari) n. [Gk. nektar, 
nectar.] A group of sub-epidermal 
cells of no definite position in a 
flower, secreting a sweet substance ; 
a nectar gland (dot.}. 

nectocalyx (ngk'toka'liks) ., necto- 
calyces (neYtoka'lisez) plu. [Gk. 
nektos, swimming ; kalyx, cup.] A 
modified medusiform person adapted 
for swimming purposes found as 
part of a Siphonophore colony 

nectocyst (nek'toslst) n. [Gk. nektos, 
swimming ; kystis, bladder.] The 
cavity of a nectocalyx (zoo/.). 

nectophore (neVtofor) n. [Gk. nektos, 
swimming ; pherein, to carry.] A 
nectocalyx ; that portion of the 
common coenosarc on which the 
nectocalyces are borne (zoo/.). 

nectopod (neVtopod) n. [Gk. nektos, 
swimming ; pous, foot.] An append- 
age modified for swimming (zoo/.). 

nectosac (ngk'tosak) n. [Gk. nektos, 
swimming ; L. saccus, sac.] A 
nectocyst (zoo/.). 

nectosome (nk'tos6m) n. [Gk. nektos, 
swimming ; soma, body.] The upper 
or swimming part of a Siphono- 
phore (zoo/.). 

nectozooid (nSk'tozo'oid) n. [Gk. 
nektos, swimming ; zoon, animal ; 
eidos, resemblance.] A nectocalyx 

negative tropism, a tendency to 
move away from a source of stimu- 
lus (phys.\ 

nekton (nek'ton) n. [Gk. nektos, 
swimming.] The organisms swim- 
ming about the surface of the sea 

nemathecium (ngm'athe'sium, ngm'- 
athe'shium) . [Gk. nema, thread ; 
theke, box.] A protuberance on the 
thallus of Thallophytes (hot.). 

nematoblast (ngm'atoblast) n. [Gk. 
nema, thread ; blastos, bud.] Sper- 

nematocalyx (ngm'atoka'llks) n. [Gk. 

nema, thread ; kalyx, cup.] The 
" Guard-polyp " of a Plumularian, 
carrying nematocysts (zoo/.). 

nematocyst (ngm'atosist) n. [Gk. 
nema, thread ; kystis, bladder.] A 
stinging cell (zoo/.). 

nematogene (nfim'atojen) n. [Gk. 
nema, thread ; genos, birth.] Appl. 
the phase of Dicyema when its 
vermiform embryos escape from 
the parent by perforating the body 
wall (zoo/.). 

nematogone (nSm'atogon) n. [Gk. 
nema, thread ; gonos, offspring.] A 
thin-walled propagative cell in cer- 
tain Mosses (oof.). 

nematophore (nem'atofor) n. [Gk. 
nema, thread ; pherein, to carry.] 
A nematocalyx (zoo/.). 

nematopnorous(nm'a.t6f'6rus) a. [Gk. 
nema, thread ; pherein, to carry.] 
Pert, a nematophore (zoo/.). 

nematozooid (nem'atozo'oid) n. [Gk. 
nema, thread ; zoon, animal ; eidos, 
resemblance.] A defensive zooid 
in a Hydrozoan (zoo/.). 

nemorose (ngm'oros) a. [L. nemus, 
woodland with pasture.] Inhabiting 
open woodland places (dot.). 

Neo-Darwinism, a revival of Dar- 
win's doctrine of natural selection 
as the chief factor in evolution, and 
of non-transmissibility of acquired 

neogamous (neog'amus) a, [Gk. neos, 
young ; gamos, marriage.] Appl. 
forms of Protozoa exhibiting pre- 
cocious association of gametocytes 

Neo-Lamarckism, a revival of 
Lamarck's doctrine of evolution, 
that inherited acquired characters 
formed the inception of specific 

Neolithic (ne'olith'Ik) a. [Gk. neos, 
young ; lithos, stone.] Pert, that 
age following on the Palaeo- 
lithic (pal.\ 

neomorph (ne'omorf) . [Gk. neos, 
young ; morphc, form.] A struc- 
tural variation from type (dioL). 

neomorphosis (ne'omor'fosis) n. [Gk. 
neos, young ; morpkosis, change.] 
Regeneration in the case where 
the new part is unlike anything in 
the body (oio/.). 

neonychium (neonTk'Ium) n. [Gk. 




neos, new ; onyx, nail.] A soft pad 
enclosing each claw of the embryo 
of all unguiculate vertebrates and 
of some other mammals, probably 
to prevent the tearing of the foetal 
membranes during movements of 
the embryo ; also found in the 
chick (zool.}. 

neopallium (ne'opal'i'um) n. [Gk. 
neos, young ; L. pallium, cloak.] 
In the mammalian brain, a definite 
area of pallium for impressions of 
tactile, visual, and other senses 

neoteinia (ne'oti'ma) n. [Gk. neos, 
young ; teinein, to stretch.] The 
state of having development arrested 
to prolong immaturity (biol.}. 

neoteinic (ne'otl'nik) a. [Gk. neos, 
young ; teinein, to stretch.] Appl. 
substitution royalties of termites 
which remain undeveloped in cer- 
tain respects (zool.}. 

neoteny (neot'Sni) n. [Gk. neos, young; 
teinein, to stretch.] The retention of 
larval characters beyond the normal 
period, or the occurrence of adult 
characteristics in the larva, ex- 
emplified in Amphibia (zool.}. 

Neotropical (ne'otrop'lkal) a. [Gk. 
neos, young ; trepein, to turn.] Pert. 
or designating a zoogeographical 
region consisting of South America, 
the Antilles, and tropical North 

Neozoic (ne'ozo'ik) a. [Gk. neos, young ; 
zoe, life.] Pert, the period from the 
Mesozoic to the present day (pal.}. 

nephric (nefrik) a. [Gk. nephros, 
kidney.] Pert, the kidney (anat.}. 

nephridial (nefrid'ial) a. [Gk. nephros, 
kidney.] Nephric, usually appl. the 
small excretory tubules in the kid- 
ney (anat.} ; alsoperf. the excretory 
organ or nephridium of Inverte- 
brates (zool.}. 

nephridiopore (nefrid'iopor) n. [Gk. 
nephros, kidney ; poros, passage.] 
The external opening of a nephridium 

nephridium (nefrid'mm) n. [Gk. 
nephros, kidney.] Any excretory 
organ ; usually the excretory organ 
of Invertebrates (zool.}. 

nephrocytes (ngf'roslts) n. plu. [Gk. 
nephros, kidney ; kytos, hollow.] 
Cells in Sponges which secrete 

waste and then migrate to the 
surface of the body to discharge 

nephrodinic (nef'rodin'lk) a. [Gk. 
nephros, kidney ; odis, labour.] 
Having one duct, serving for both 
excretory and genital purposes 

nephrogonaduct (nef'rogon'adukt) n. 
[Gk. nephros, kidney ; gonos, off- 
spring ; L. ducere, to lead.] Ex- 
cretory and genital duct in one 

nephroid (ngf'roid) a. [Gk. nephros, 
kidney ; eidos, resemblance.] Kid- 
ney-shaped (anat., zool.}. 

nephrolytic (nef'rdllt'ik) a. [Gk. 
nephros, kidney ; lyein, to dissolve.] 
Pert, or designating enzymatic 
action destructive to the kidneys 

nephropore (nef 'ropor). \G\s..nephros, 
kidney ; poros, passage.] A neph- 
ridiopore (zool.}. 

nephros (nef'ros) n. [Gk. nephros, 
kidney.] A kidney ; usually the 
functional portion of a kidney 

nephrostome (nefrostom) n. [Gk. 
nephros, kidney ; stoma, mouth.] 
The opening of a nephridial tubule 
into the coelom or body cavity 
(zool.}. ' 

nephrotome (ngf'rotom) n. [Gk. 
nephros, kidney ; temnein, to cut.] 
That part of a somite developing 
into an embryonic excretory organ 

nervated (ngr'vatgd) a. [L. nervus, 
sinew.] Having nerves or veins 

nervation (nerva'shun) n. [L. nervus, 
sinew.] The disposition of nerves 
in a leaf (bot.}. 

nerve (nerv) n. [L. nervus, sinew.] 
One of the numerous grey fibrous 
cords connecting the brain with all 
other parts of the body (anat.} ; the 
vein of an insect wing (zool.} ; a 
vein (dot.}. 

nerve canal, a canal for passage of 
nerve to the pulp of a tooth (anat.}. 

nerve cell, a cell characteristic of 
brain and nerve tissue (anat.}. 

nerve centre, a collection of nerve 
cells associated with one particular 
function (phys.}. 




nerve eminence, a superficial group 
of cells in some Fishes, acting as a 
sense organ and connected with 
the lateral line system (zool.). 

nerve ending, the terminal distal 
portion of a nerve, modified in 
various ways (anat.). 

nerve fibres, the thread-like struc- 
tures of which nerves are composed 

nerve pentagon, the five-sided nerve 
ring round the mouth of Echino- 
derms (zoo!.). 

nervimotion (nerVimo'shun) n. [L. 
nervus, sinew ; movere, to move.] 
Motion due to direct stimulus from 
nerves (phys.). 

nervous (neYvus) a. [L. nervus, 
sinew.] Pert. or designating 
nerves ; appl. tissue composed of 
nerve fibres (anat.). 

nervous system, the brain, spinal 
cord, nerves and all their branches 
taken collectively (anat.). 

nervule (neYvul) n. [L. dim. of 
nervus, sinew.] A branch or 
terminal portion of a nervure of 
an insect wing (zool.). 

nervuration (ner'vura'shun) . [L. 
nervus, sinew.] Disposition of 
nervures (zool.). 

nervure (nerVur) n. [L. nervus, 
sinew.] One of the rib-like struc- 
tures which support the membran- 
ous wings of Insects, branches of the 
tracheal system (zool.); a vein (dot.). 

nervus lateralis (neVvus lat'gral'is) n. 
[L. nervus, sinew ; lateralis, pert. 
the side.] A branch of the vagus 
nerve in Fishes connecting the 
sensory "lateral line" with the 
brain (anat.). 

net-knots, karyosomes. 

netted-veined, with veins in the 
form of a network (bot.). 

nettling-cells, the stinging cells in 
Hydra and its allies (zoo!.). 

neurad (nu'rad) adv. [Gk. neuron, 
nerve.] Dorsally (anat.). 

neural (nu'ral) a. [Gk. neuron, 
nerve.] Pert, or closely con- 
nected with nerves (anal.). 

neural arch, the arch formed on 
the dorsal surface of a vertebral 
centrum, by the neural plates and 
neural spine, for the passage of 
the spinal cord (anat.). 

neural canal, the canal formed by 
the neural arches (anat.). 

neural plates, the lateral members 
of a neural arch (anat.) ; the median 
row, usually of eight bony plates, 
in the carapace of a turtle (zool.). 

neurapophysis (nuYapSf'isfs) n. [Gk. 
neuron, nerve ; apo, from ; phyein, 
to grow.] The spinous process of 
a vertebra (anat.). 

neuraxis (nurak'sis) n. [Gk. neuron, 
nerve ; L. axis, axle.] The central 
cylinder of a medullated nerve- 
fibre (anat.). 

neuraxon (nurak'son) n. [Gk. neuron, 
nerve ; axon, axle.] Neuraxis. 

neurenteric (nur'gnteYik, nurgn'terik) 
a. [Gk. neuron, nerve ; enteron, 
gut] Pert, the neurocoele and 
enteric cavity (anat.). 

neurenteric canal, a short canal 
connecting the posterior end of 
the central canal of the spinal 
cord with the posterior end of the 
enteric cavity (emb.). 

neuric (nu'rik) a. [Gk. neuron, nerve.] 

neuricity (nuris'itl) n. [Gk. neuron, 
nerve.] Property peculiar to nerves 

neurillty (nuril'iti) . [Gk. neuron, 
nerve.] The stimuli - transmitting 
capacity of nerves (phys.). 

neuroblast (nu'roblast) n. [Gk. 
neuron, nerve ; blastos, bud.] 
Special epithelial cells from which 
nerve cells are formed (emb.). 

neurocentral (nu'rosSn'tral) a. [Gk. 
neuron, nerve ; L. centrum, centre.] 
Appl. two vertebral synchondroses 
persisting during the first few years 
of life (anat.). 

neurocirrus (nu'rostr'us) n. [Gk. 
neuron, nerve ; L. cirrus, curl.] 
The cirrus of the neuropodium of 
a polychaet Annelid (zool.). 

neurocoel (nu'rosel) n. [Gk. neuron, 
nerve ; koilos, hollow.] The cavityof 
the central nervous system (anat.). 

neurocyte (nu'rosit) n. [Gk. neuron, 
nerve ; kytos, hollow.] Nerve cell 

neurodendron(nu'r6den'dron). [Gk. 
neuron, nerve ; dendron, tree.] A 

n euro-epithelium (n u'ro - gplth e'lfu m ) 
n. [Gk. neuron, nerve ; epi, upon ; 




thele, nipple.] The superficial layer 
of cells where specialized for a sense- 
organ (anat.}. 

neuroflbrils (nu'rofi'brilz) n. plu. [Gk. 
neuron, nerve ; L. fibrilla, fine fibre.] 
Exceedingly fine fibres of which 
a medullated nerve fibre is com- 
posed ; also present in nerve cells, 
and believed to be the conductors 
of nerve impulses (anat.}. 

neurogenesis (nu'rojen'esis) n. [Gk. 
neuron, nerve ; gignesthai, to pro- 
duce.] Nerve production (phys.}. 

neuroglia (nu'rogle'a, nurog'lia) n. 
[Gk. neuron, nerve ; glia, glue.] 
A peculiar tissue, composed of cells 
and fibres, supporting the nerve 
cells and nerve fibres (anat.}. 

neurold (nu'roid) a. [Gk. neuron, 
nerve ; eidos, resemblance.] Like 
a nerve (anal.}. 

neurokeratin (nu'roker'atm) n. [Gk. 
neuron, nerve ; keras, horn.] The 
keratin of nervous tissue (phys.}. 

neurolemma (nu'rolem'a) n. [Gk. 
neuron, nerve ; lemma, skin.] The 
delicate tubular sheath of a nerve 

neurology (nurol'qji) n. [Gk. neuron, 
nerve ; logos, discourse.] That 
part of anatomy dealing with the 
details of the nervous system. 

neuroraasts (nu'romasts) n. plu. 
[Gk. neuron, nerve ; inastos, knoll.] 
Groups of sensory cells in the 
lateral line of Fishes (zool.}. 

neuromere (nu'romer) n. [Gk. neuron, 
nerve ; meros, part.] A spinal seg- 
ment, a division of convenience not 
structural (anat.}. 

neuromuscular (nu'romus'kular) a. 
[Gk. neuron, nerve ; L. nmsculus, 
muscle.] Pert, nerve and muscle 
(anat ). 

neuron (nu'ron) n. [Gk. neuron, nerve.] 
The nerve-cell with its outgrowths 
(anat.} ; also neurone. 

neuroneme (nu'ronem) n. [Gk. neuron, 
nerve ; nema, thread.] A nerve 
fibril running parallel to a myoneme 
in an Infusorian (zool.}. 

neuronephroblast (nu'roneTroblast) 
n. [Gk. neuron, nerve ; nephros, 
kidney ; blastos, bud.] One of cells 
derived from one of the megameres 
in the segmenting egg of Clepsine, 
which later give rise to part of the 

germinal bands from which the 
nerve cord and the nephridia de- 
velop (zool.}. 

neurophags (nu'rofagz) n. plu. [Gk. 
neuron, nerve ; phagetn, to eat.] 
Phagocytic cells that encroach upon 
and destroy nerve-cells in old age 

neurophane (nu'rofan) a. [Gk. neuron, 
nerve ; phainein, to appear.] Ner- 
vous, sensory ; appl. supposed ner- 
vous fibrils of Ciliata (zool.}. 

neuropodium (nu'ropo'dium) n. [Gk. 
neuron, nerve ; pous, foot.] The 
ventral lobe of a polychaetan para- 
podium (zool.}. 

neuropodous (nurop'odus) a. [Gk. 
neuron, nerve ; pous, foot.] " Hav- 
ing limbs directed towards the 
neural side " (zool}. 

neuropore (nu'ropor) n. [Gk. neuron, 
nerve ; poros, passage.] The an- 
terior opening of the neurocoel to 
the exterior (einb.}. 

neuropterous (nurop'terus) a. [Gk. 
neuron, nerve; ptcron, wing.] Hav- 
ing wings with a network of ner- 
vures (zool.}. 

neuroskeleton (nu'roskel'eton) n. [Gk. 
neuron, nerve ; skeletos, dried up.] 
Endoskeleton (zool.}. 

neurosynapse (nu'rosmaps') n. [Gk. 
neuron, nerve ; synopsis, union.] 
Junction of nerve-cells through 
terminal arborizations or cell pro- 
cesses (anat.}. 

neurotendinous (nu'roten'dlnus) a. 
[Gk. neuron, nerve ; tenon, tendon.] 
Concerning nerves and tendons 

neurotrophic (nu'rotrof'ik) a. [Gk. 
neuron, nerve ; trephein, to nourish.] 
Nourishing the nervous system 

neurotropism (nurot'roptzm) n. [Gk. 
neuron, nerve ; trepein, to turn.] The 
attraction exerted by nervous tissue 
upon developing nerve tissue (phys.}. 

neuter (nu'ter) a. [L. neuter, of 
neither sex.] Sexless. 

neutral (nu'tral) a. [L. neuter, neuter.] 
Neither male nor female (zool.}. 

neutrophil (nu'troftl) a. [L. neuter, 
neuter ; Gk. philein, to love.] Des- 
ignating granules of white blood 
corpuscles, which stain only with 
neutral stains (cyt.}. 




neutrophilic, neutrophil. 

nictitant (nik'titant) a. [L. nictare, 
to wink.] Appl. an ocellus with 
central lunate spot (zool.}. 

nictitating membrane, the third 
eyelid, a transparent membrane 
which assists in keeping the eye 
clean (zool.}. 

nidamental (nid'amgn'tal) a. [L. 
nidus, nest.] Appl. glands which 
secrete material for an egg-covering 

nidation (mda'shun) n. [L. nidus, 
nest.] The renewal of the uterus 
lining between menstrual periods 

nidicolous (nldlk'olus) a. [L. nidus, 
nest ; colere, to cultivate.] Living 
in the nest for a time after hatching 

nidifugous (nidlf'ugus) a. [L. nidus, 
nest ; fugere, to flee.] Leaving the 
nest soon after hatching (zool.}. 

nidulus (nid'ulus) n, [L. dim. of 
nidus, nest.] The nucleus from 
which a nerve originates (anat.}. 

nidus (nl'dus) n. [L. nidus, nest.] 
A nest ; a nest-like hollow (zool.} ; 
a nucleus (anat.} ; a cavity for the 
development of spores (hot.}. 

nidus hirundinalis (hirun'dlna'lTs) n. 
A fossa of the cerebellum (anaf.). 

nigrescent (ntgrSs'6nt) a. [L. nig- 
rescere, to turn black.] Approach- 
ing to black in colour (zool.}. 

nipple (ntp'l) n. [Dim. of A.S. nib, 
for neb, nose.] Mamma ; teat (anat., 

Nissl's granules, angular particles 
found in the cytoplasm of nerve 
cells (phys.}. 

nisus formativus (nfsus formatl'vus) 
n. [L. niti, to strive ; formare, to 
form.] The tendency to reproduce. 

nitid (nit'id) a. [L nitidus, shining.] 

nit id cms (nft'idus) a. [L. nitidus, 
shining.] Glossy. 

nitrobacteria (ni'trobakte'ria) n. plu. 
[L. nitruin, natron ; bacterium, 
bacterium.] The nitric bacteria of 
the soil (bot.}. 

nitrogen (nftrojgn) n. [Gk. nitron, 
soda ; genos, descent.] An ele- 
mentary gas composing four-fifths 
of the volume of the atmosphere 

nitrogenous (nltroj'Snus) a. [Gk. 
nitron, soda ; genos, descent.] Pert. 
or containing nitrogen. 

nitrogenous equilibrium, equili- 
brium of body maintained by 
equality of income and output of 
nitrogen (phys.}. 

nitrophilous (nltrof'Ilus) a. [Gk. 
nitron, soda ; philein, to love.] 
Thriving in nitrogenous soils (dot.}. 

noctilucent (nok'tiloo'sgnt, -lu'-) a. 
[L. nox, night ; lux, light.] Phos- 
phorescent (biol.}. 

nocturnal (noktur'nal) a. [L. nox, 
night.] Seeking food and moving 
about at night, and not in the 
day-time (zool.}. 

nodal (no'dal) a. [L. nodus, knob.] 
Pert, a node (bot., zool.}. 

node (nod) n. [L. nodus, knob.] The 
knob or joint of a stem at which 
leaves arise (bot,}. 

nodose (no'dos) a. [L. nodus, knob.] 
Having the intermediate and ter- 
minal joints thicker than the re- 
mainder ; having knots or swellings 
(zool, bot.}. 

nodular (nod'ular) a. [L. nodulus, 
dim. of nodus, knob.] Pert, a 
nodule or knot (bot., zool.}. 

nodule (nod'ul) n. [L. nodulus, dim. 
of nodus, knob.] A small knob- 
like structure. 

noduliferous (nod'ullf'e'rus) a. [L. 
nodus, knob ; ferre, to carry.] 
Bearing a nodule ; a.ppl. roots of 
leguminous plants (bot.}. 

nodulus (nod'ulus) n. [L. nodulus, 
dim. of nodus, knob.] A nodule. 

nodus (no'dus) . [L. nodus, knob.] 
A knob or node. 

nomenclature (no'me'nkla.'tur, 
nomgn'klatur) n. [L. nomen, name ; 
calare, to call.] System of naming 
plants, animals, organs, etc. 

norma (nor'ma) n. [L. nornia, rule.] 
View of the skull as a whole from 
certain points (anat.}. 

normal (nor'mal) a. [L. norma, rule.] 
Consistent with type or standard. 

normoblasts (nor'moblasts) n. plu. 
[L. norma, rule ; Gk. blastos, bud.] 
Erythroblasts, which see. 

nostrils (nSs'trilz) . plu. [A.S. 
nosthyrl, nostril.] The external 
openings of the nose (anat.}. 

notochordal (no'tokor'dal) a. [Gk. 




noton, back ; chorde, cord.] Pert. 
or enveloping the notochord ; appL 
sheath, tissue, etc. (anaf.). 

notocirrus (no'tosir'us) n. [L. notum, 
back ; cirrus, curl.] The cirrus of 
the notopodium of a polychaet 
Annelid (zool.}. 

notonectal (no'tonek'tal) a. [Gk. 
noton, back ; nektos, swimming.] 
AppL Notonectidae, which swim 
back downwards (zool.}. 

notopodium (no'topo'dium) n. [Gk. 
noton, back ; pous, foot.] The 
dorsal lobe of a polychaetan para- 
podium (zoo/.}. 

nototribe (no'totrib) a. [Gk. noton, 
back ; tribein, to rub.] AppL 
flowers whose anthers and stigma 
touch the back of insects as they 
enter the calyx, a device for secur- 
ing cross-fertilization (bot.}. 

notum (no'tum) n. [L. notum, back.] 
The dorsal portion of an insect 
segment ; tergum (zool.}. 

nucellus (nusel'us) n. [L. dim. of 
nux, nut.] The central region and 
chief part of an ovule (hot.). 

nuchal (nu'kal) a. [L. L. nucha, spinal 
marrow.] AppL two sense organs 
regarded as olfactory, on the 
prostomium of Chaetopoda (zool.}. 

nuchal cartilage, a thin shield- 
shaped plate on the posterior 
surface of the neck of Sepia 

nuciferous (nusiferus) a. [L. nux, 
nut ; ferre, to carry.] Nut-bearing 

nucivorous (nusi/orus) a. [L. nux, 
nut ; -vorare, to devour.] Nut- 
eating (zool.}. 

nuclear (nu'klear) a. [L. nucleus, 
kernel.] Pert, the nucleus (bot., 

nuclear disc, a star-like structure 
formed by the chromosomes in the 
equator of the spindle during 
mitosis (cyt."). 

nuclear membrane, the delicate 
membrane bounding a nucleus, 
formed from the surrounding 
cytoplasm (cyt.}. 

nuclear plate, the equatorial plate 

nuclear spindle, a barrel - shaped 
structure formed of a number of 
fine fibrils in the cytoplasm sur- 

rounding the nucleus, a stage in 
mitosis (cyt.}. 

nucleate (nu'kleat) a. [L. nucleus, 
nucleus.] Having a nucleus (cyt.}. 

nucleation (nuklea'shun) a. [L. 
nucleus, kernel.] Nucleus forma- 
tion (cyt.}. 

nucleic (nu'kleik) a. [L. nucleus, 
kernel.] Pert, an acid containing 
phosphorus, found in some nuclei 

nucleiform (nu'klelform) a. [L. 
nucleus, kernel ; forma, shape.] 
Shaped like a nucleus (cyt.}. 

nuclein (nu'klein) n. [L. nucleus, 
kernel.] One of the chemical 
compounds found in nuclei, 
similar to protein but with the 
addition of phosphorus (phys.\ 

nucleochylema (nu'kleoklle'ma) n. 
[L. nucleus, kernel ; Gk. chylos, 
juice.] The ground substance of 
a cell-nucleus (cyt.}. 

nucleohyaloplasm (nu'kleohl'alo- 
plazm) n. [L. nucleus, kernel ; Gk. 
hyalos, glass ; plasma, something 
moulded.] The semi-fluid ground- 
substance of a nucleus (cyt.}. 

nucleolar (nukle'b'lar) a. [L. nucleus, 
kernel.] Pert, a nucleolus (cyt.}. 

nucleolus (nukle'olus) n. [L. nucle- 
olus, dim. of nucleus, little kernel.] 
A rounded mass of pure plastin 
occurring in a nucleus (cyt.^. 

nucleomicrosomes (nu'kleoml'kro- 
somz) n. plu. [L. nucleus, kernel ; 
Gk. mikros, small ; soma, body.] 
Nuclear chromatin granules (cyt.}. 

nucleoplasm (nu'kleoplazm) n. [L. 
nucleus, kernel ; Gk. plasma, some- 
thing moulded.] Reticular nuclear 
substance ; cf. cytoplasm (cyt.}. 

nucleoproteid (nu'kleb'pro'teid) n. 
[L. nucleus, kernel ; Gk. protos, 
first ; eidos, resemblance.] A nu- 
clein with much albumin (phys.}. 

nucleus (nu'kleus) n. [L. nucleus, 
kernel.] A complex spheroidal 
mass essential to the life of a 
cell (cyt.}. 

nuculanium (nu'kula'mum) n. [L. 
nucula, small nut.] A fleshy fruit 
like a grape (bot.}. 

nudibranchiate (nu'dibrang'kiat) a. 
[L. nudus, naked ; Gk. brangchia, 
gills.] Having gills not covered by a 
protective shell or membrane (zool.}. 




nudicaudate (nu'dlkod'at) a. [L. 
nudus, naked ; cauda, tail.] Having 
a tail not coveredbyhairorfur(.sw/.). 

nudlcaulous (nu'dikol'us) a. [L. 
nudus, naked ; caulis, stem.] Appl, 
stems without leaves (dot.}. 

nudlflorous (nu'diflo'rus). [L. nudus, 
naked ;flos, flower.] Having flowers 
without glands or hairs (bot). 

nummulation (num'ula'shun) n. [L. 
nummus, coin.] The tendency of 
red blood corpuscles to adhere 
together like piles of coins (phys). 

nummulitic (num'ulit'ik) a. [L. num- 
mus, coin.] Like or pert, a Num- 
mulite (zool., pal.}. 

nuptial flight, the flight taken by 
the queen bee when fertilization 
takes place (zool.}. 

nurse cells, single cells or layers of 
cells attached to or surrounding 
an egg-cell, probably for elaboration 
of its food-material (cyt.}. 

nurse generation, an asexual bud- 
ding generation of some Tunicates, 
in which the phorozooids act as 
foster parents to the later formed 
buds, the gonozooids (zool.}. 

nut (nut) n. [A.S. knutu, nut.] A 
dry, hard, indehiscent one-celled 
fruit (bot.). 

nutation (nuta'shun) n. [L. nutare, 
to nod.] Curvature or change of 
position in organs of a growing 
plant (hot.}. 

nutlet (nut'let) n. [Dim. of nut.] The 
stone formed in drupaceous fruits 

nutricism (nu'trisizm) n. [L. nutrix, 
nurse.] Symbiotic relationship with 
all the benefit to one partner (biol.). 

nutrition (nutrish'un) n. [L. nutrix, 
nurse.] The ingestion and assimila- 
tion of food materials of animals 
and plants (phys). 

nutritive (nu'tritlv) a. [L. nutrix, 
nurse.] Concerned in the function 
of nutrition ; appl. yolk, polyp, 
zooid, plasma. 

nyctipelagic (nlk'tfpelaj'ik) a. [Gk. 
nyktios, nightly ; pelagos, the sea.] 
Rising to the surface of the sea 
only at night (zool.}. 

nyctitropism (niktit'ropizm) n. [Gk. 
nyktios, nightly ; trepein, to turn.] 
Tendency of certain leaves to curve 
upwards at night (bot.). 

nymph (ntmf) n. [Gk. nymphe, bride.] 
A stage following the larval in 
insect metamorphosis (zool.). 

bride.] The labia minora (anat.). 


oar-feathers, the wing feathers used 
in flight in Birds (zool.). 

obcompressed (ob'komprgst') a. [L. 
o&, towards ; comprimere, to com- 
press.] Flattened in a vertical 
direction (bot.). 

obcordate (obkor'da.t) a. [L. ob, 
against ; cor, the heart.] Heart- 
shaped ; appl. leaves which have 
the stalk attached to the apex of 
the heart (bot.}. 

obdiplostemonous (6bdiplost6m'6nus) 
a. [L. 06, against ; Gk. diploos, 
double ; stemon, a warp.] With 
the outer series of stamens opposite 
the petals (bot). 

obelion (obe'lion) n. [Gk. obelos^ a 
spit.] The point between the two 
foramina on the interparietal suture 

obex (o'beks) n. [L. obex, an obstacle.] 
A triangular layer of grey matter 
above the calamus in the roof of 
the fourth ventricle (anat.). 

obimbricate (obtm'brikat) a. [L. ob, 
in the way ; imbrex, a tile.] With 
regularly overlapping scales, with 
the overlapping ends downwards 

oblanceolate (oblan'seolat) a. [L. ob, 
reversely ; lancea, a spear.] In- 
versely lanceolate (bot.). 

obligate or obligatory parasites, 
parasites which are limited to one 
mode of life, and cannot exist inde- 
pendently of a host ; cf. facultative 

oblique- (oblek') a. [L. obliquus, bent.] 
Placed obliquely ; appl. certain 
muscles (anat.) ; asymmetrical (bot.). 

obliquus (oble'kwus) a. [L. obliquus, 
bent.] Oblique ; appl. muscles 

obliterate (obllt'grat) a. [L. ob^ re- 
versely ; litera, a letter.] Indis- 
tinct or profuse ; appl. markings on 
insects (zool.). 




obovate (obo'vat) a. [L. ob, reversely ; 
ovum, an egg.] Egg-shaped, with 
the narrow end attached to the 
stalk (tot.). 

obovoid (obo'void) a. [L. ob, against ; 
ovum, an egg ; Gk. eidos, shape.] 
Inversely ovoid ; roughly egg- 
shaped, with the narrow end down- 
wards (bot.). 

obsolescence (obsoles'ens) n. [L. 
obsolescere, to wear out.] The 
gradual reduction and consequent 
disappearance of anorganism (biol.) ; 
a blurred portion of a marking on 
any animal (zoo/.). 

obsolete (ob'solet) a. [L. obsolescere, 
to wear out.] Wearing out or dis- 
appearing ; appl. any character that 
is becoming less and less distinct 
in each succeeding generation 

obturator (ob'tura'tor) a. [L. obturare, 

to close.] Pert, any structure in 

the neighbourhood of the obturator 

foramen (anaf.). 

obturator foramen, an oval foramen 

between ischium and pubis (zoo/.). 
obtusilingual (obtusiling'gwal) a. [L. 
obtundere, to make blunt ; lingua, 
a tongue.] Short-tongued (zoo/.). 
obumbrate (obum'brat) a. [L. 
obumbrare, to overshadow.] With 
some structure overhanging the 
part so as to conceal it partially 

obverse (ob'vers, obvers') a. [L. 
obvertere, to turn round.] With 
the base narrower than the apex 

obvolute (ob'volut) a. [L. obvolvere, 
to wrap round.] Overlapping ; 
appl. leaves when half of one leaf 
is wrapped round half of another 
similar leaf (bot.). 

obvolvent (obvol'vent) a. [L. 
obvolvere, to wrap round.] Bent 
downwards and inwards ; appl. 
wings, elytra of insects, etc. (zoo/.). 
occipital (oksip'ital) a. [L. occiput, 
back of the head.] Pert, the back 
part of the head or the occipital 
bones (anaf., zoo/.). 
occipitalia (ok'sipita'lia) n. plu. [L. 
occiput, back of the head.] The 
group of parts of the cartilaginous 
brain case forming the back part 
of the head (zoo/.). 

occiput (ok'sipoot, ok'sipiit) . [L. 
occiput, back of the head.] The 
occipital region of the skull 
(anaf.) ; the back of an insect's 
head (zoo!.). 

occlude (oklood') v. [L. occluderc, 
to shut in.] To absorb (phys.}. 

occlusor (okloo'sor) a. [L. occludere, 
to shut in.] Appl. muscles of an 
operculum or movable lid (zoo/.). 

ocellate (b'sel'at) a. [L. ocellus, a 
little eye.] Like an eye or eyes ; 
appl. markings on many animals 

ocellated (osel'ated, os'elated) a. [L. 
ocellus, a little eye.] Having ocelli ; 
having eye-like spots or markings 

ocellation (os'ela'shun) ;/. [L. ocellus, 
a little eye.] Condition of having 
ocelli, or of having ocellate mark- 
ings ; ocellate marking (zoo/.). 

ocelli ferous (os'elif'erus) a. [L. 
ocellus, a little eye ; ferre, to bear.] 
Ocellated, which see. 

ocellus (osel'us) ., ocelli (osel'i, 
osel'e) plu. [L. ocellus, a little 
eye.] A simple single eye or eye- 
spot found in many of the lower 
animals ; an eye-like marking as 
seen in many Insects (zoo/.). 

ochrea, ocrea (ok'rea, o'krea) n. [L. 
ocrea, a greave.] A tubular sheath - 
like expansion at the base of the 
petiole (bot.} ; a sheath (zoo/.). 

ocreaceous (ok'rea'shus) a. [L. ocrea, 
agreave.] Ocrea-like; appl. various 
structures in plants and animals. 

ocreate (ok'reat) a. [L. ocrea, a 
greave.] Having an ocrea (bot.} ; 
booted, sheathed (zoo/.). 

octactine (oktak'tin) n. [Gk. okta, 
eight ; aktis, a ray.] A type of 
sponge spicule with eight rays, a 
modification of a hexactine (zoo/.). 

octamerous (oktam'eriis) a. [Gk. 
okta, eight ; meros, a part.] Appl. 
organs or parts of organs when 
arranged in eights ; appl. parts of 
whorls of certain plants (bot.} ; 
appl. parts of certain Alcyonaria 

octandrous (oktan'drus) a. [Gk. okta, 
eight ; aner, a man.] Having eight 
stamens (bot.}. 

octant (ok'tant) n. [L. octo, eight.] 
One of the eight cells formed by 




the division of the fertilized ovule 

in plants (dot.) ; one of the units 

in the eight-celled stage in the 

segmentation of the ovum (zool.}. 
octogynous (oktoj'mus) a. [Gk. okta, 

eight ; gyne, a woman.] Having 

eight pistils (bot.}. 
octopetalous (ok'topeYalus) a. [Gk. 

okta, eight ; petalon, a petal.] 

Having eight petals (hot.). 
octopod (ok'topod) a. [Gk. okta, 

eight ; pous, a foot.] Having 

eight feet or arms (zool.'). 
octoradiate (ok'tora'diat) a. [L. octo, 

eight ; radius, a spoke.] Having 

eight rays or arms (zool.}. 
octosepalous (ok'tosep'alus) a. [Gk. 

06 fa, eight ; sepalon, a sepal.] 

Having eight sepals (bot.}. 
octosporous (ok'tospo'rus, oktos'porus) 

a. [Gk. okta, eight ; sporos, a seed.] 

Having eight spores (bot.}. 
octostichous (oktSs'tikus) a. [Gk. 

okta, eight ; stichos, a row.] Having 

the leaves in eights, as in phyllo- 

taxis (bot.}. 
octozolc (ok'tozo'lk) a. [Gk. okta, 

eight ; zoon, an animal.] Appl. 

a spore of Gregarines, containing 

eight sporozoites (zool.}. 
ocular (Sk'ular) a. [L. oculus, an eye.] 

Pert, or perceived by the eye. 
ocular lobe, the projecting thoracic 

lobe in some beetles (zool.}. 
ocular plates, the plates at the 

end of the ambulacral areas in sea 

urchins (zool.}. 
oculate (ok'ulat) a. [L. oculus, an 

eye.] Having eyes, or having eye- 
like spots (zool.}. 
ocullferous (ok'ulTf'Srus), oculigerous 

(6k'ulTj'6riis) a. [L. oculus, eye; 

ferre, gerere, to carry.] Bearing 

eyes (zool.}. 
oculofrontal (ok'ulofriin'tal) a. [L. 

oculus, eye ; frons, forehead.] Pert. 

region of forehead and eye. 
oculomotor (6k'uloino't6r) a. [L. 

oculus, eye ; move re, to move.] 

Causing the movements of the 

eyeball ; appl. the third cranial 

nerve (anat., zool.}. 
oculonasal (ok'ulona'zal) a. [L. ocuhts, 

eye; nasus, nose.] Pert, eye and nose. 
oculus (Sk'ulus) n. [L. oculus, eye.] 

The eye (anat., zool.} ; a leaf-bud in 

a tuber (bot.}. 

odontoblast (odon'toblSst) . [Gk. 
odous, a tooth ; blastos, a bud.] 
One of the columnar cells on the 
outside of the pulp that form the 
dentine (zool.}. 

odontoclast (odfin'toklast) n. [Gk. 
odous, a tooth ; klan, to break.] 
One of the large multinucleate 
cells that absorb the roots of the 
milk teeth (zool.}. 

odontogeny (odontqj'eni) n. [Gk. 
odous, tooth ; genos, offspring.] The 
origin and development of teeth. 

odontoid (odon'toid) a. [Gk. odous, 
tooth ; eidos, form.] Tooth-like ; 
pert, the odontoid process. 

odontoid process, a tooth-like peg 
on the axis round which the atlas 
rotates, it is the centrum of the 
atlas, which has first become free 
and finally fused with the axis 
(anat., zool.}. 

odontophore (odSn'tofor) n. [Gk. 
odour, tooth ; pherein, to carry.] 
The radula or tooth-bearing organ 
in Molluscs; a structure over which 
the radula slides (zool}. 

odontoplast (6d8n'topl&st) n. [Gk. 
odous, tooth ; plastos, moulded.] 
An odontoblast cell (anat.}. 

odontostomatous (odon'tostom'atus) 
a. [Gk. odous, tooth ; stoma, mouth.] 
Having tooth-bearing jaws. 

oecoid (e'koid) n. [Gk. oikos, a house.] 
The stroma of a blood corpuscle 

ecology (ekol'qjl) n. [Gk. oikos, 
house ; logos, discourse.] Bio- 
nomics, which see. 

oedematin (edgm'atin) n. [Gk. oidema, 
a swelling.] The microsomes of 
the ground substance of the nucleus 

oenocyte (e'nosit) n. [Gk. oinos, wine ; 
kytos, hollow.] One of the large 
cells from the clusters which sur- 
round the trachea and fat body of 
Insects (zool.}. 

oesophageal (esof'aje'al) a. [Gk. 
oisophagos, the gullet.] Pert, or 
near the oesophagus, as ganglia 

oesophagus (esof'agiis) n. [Gk. 
oisophagos, the gullet.] That part 
of the alimentary canal between the 
pharynx and the stomach, or part 
equivalent thereto (zool.}. 




oestrual (e'strooal) a. [Gk. oistros, 
gadfly.] Pert, oestrus (phys.} ; also 

oestruatlon (e'strooa'shun) n. [Gk. 
oistros, gadfly.] State of being 
under sexual desire ; rut (phys.}. 

oestrus (e'strus) n. [Gk. oistros, gad- 
fly.] The sexual heat of animals ; 
rut (phys.}. 

offset, a short prostratebranch which 
takes root at the apex and develops 
new individuals (hot.}. 

offshoot, a lateral shoot from a main 
stem (hot.). 

oidium (oid'ium) n. [Gk. oon, an 
egg.] The conidial stage of some 
of the mildews (bot.}. 

oikoplast (oik'oplast) n. [Gk. oikos, 
house ; plastos, moulded?) One of 
the large glandular ectoderm cells 
which form the gelatinous layer of 
Appendicularians (zool.}. 

oilgland, the uropygial gland in 
Birds ; a gland which secretes oil 

oleaginous (61'eaj'inus) a. [L. olea, 
oil.] Pert, oil ; containing oil ; 
producing oil (biol.}. 

olecranon (olgk'ranon) n. [Gk. olene, 
elbow.] A large process at the 
upper end of the ulna (zool.}. 

oleiferous (oleif'Srus) a. [L. oleum, 
oil ; fern, to carry.] Producing oil 

oleln (6'lem) n. [L. oleum, oil.] A 
fat found in animal and vegetable 
tissues and liquid at ordinary tem- 
peratures (phys.}. 

oleocyst (6'leosist) n. [L. oleum, oil ; 
Gk. kystis, bladder.] A diverticu- 
lum of the nectocalyx (zool.}. 

olfactory (61fak'torT) a. [L. olere, to 
have a smell ; facere, to make.] 
Pert, associated with, or designating 
the structures associated with the 
sense of smell. 

olfactory lobe, a small lobe project- 
ing from the anterior lower margin 
of the cerebral hemispheres (anat.}. 

olfactory pit, any olfactory organ 
of the nature of a small pit or 
hollow (zool.} ; the depression which 
later forms the nasal passage (eml>.). 

oligacanthous (61'Igakan'thus) a. [Gk. 
oligos, few ; akantha, a spine.] 
Bearing few spines (zool.}. 

oligandrous (ol'igan'drus) a. [Gk. 

oligos, few ; aner, man.] Having 
few stamens (hot.}. 

oligocarpous (ol'igokar'pus) a. [Gk. 
oligos, few ; karpos, fruit.] Having 
few carpels (hot.}. 

Oligocene (61'igosen') a. [Gk. oligos, 
few ; kainos, recent.] Appl. a terti- 
ary period between Eocene and 
Miocene (pal.}. 

ollgodynamic (ol'igodinam'ik) a. 
[Gk. oligos, few ; dynamis, power.] 
Caused by small or minute forces 

oligomerous (ol'igom'erus) a. [Gk. 
oligos, few ; meros, a part.] Hav- 
ing one or more of the whorls with 
fewer members than the rest (bot.}. 

oligonephrous (ol'igonef'rus) a. [Gk. 
oligos, few ; nephros, a kidney.] 
Having few Malpighian tubules ; 
appl. Insects (zool.}. 

oligospermous (ol'Igosper'mus) a. 
[Gk. oligos, few ; sperma, a seed.] 
Bearing few seeds (bot.}. 

oligostemonous (ol'Igostern'onus) a. 
[Gk. oligos, few ; stemon, a stamen.] 
Having few stamens (bot.}. 

oligotaxy (61'igotak'si) n. [Gk. oligos, 
few ; taxis, arrangement.] Diminu- 
tion in the number of whorls (bot.}. 

oligotokous (ol'fgot'okus) a. [Gk. 
oligos* few ; tokos, offspring.] Bear- 
ing few young (zool.}. 

oliva (oli'va), olive (61'iv) n. [L. 
oliva, olive.] A prominence on 
each side of the anterior end of the 
medulla just below the pons (anat}. 

olivary (61'ivari) a. [L. oliva, olive.] 
Pert, the oliva, or olivary body 

omasum (oma'sum) n. [L. omasum, 
paunch.] The psalterium or third 
division of a ruminant's stomach 
. (zool.}. 

omental (6'mSn'tal) a. [L. omentum, 
a fold.] Pert, the omentum or 
omenta (anat.}. 

omentum (om&n'tum) n. [L. omentum, 
a fold.] A fold of the peritoneum 
either free or acting as the con- 
necting link between viscera, etc. 

ommateum (om'ate'um) n. [Gk. 
omma, the eye.] Any compound 
eye (zool.}. 

ommatidium (om'atid'ium) n. [Gk. 
omma, eye.] One of the com- 




ponent elements of a compound 
eye (zoo/.). 

ommatoids (om'a'toidz) n. pin. [Gk. 
omma, eye ; eidos, form.] Two or 
four light-coloured spots on the 
last abdominal segment of Pedi- 
palpi, of disputed function (zoo/.). 

ommatophore (Sm'atofor) n. [Gk. 
omma, eye ; pherein, to bear.] 
Any movable process bearing an 
eye (zoo/.). 

omnivorous (omniv'orus) a. [L. 
omnis, all ; vorare, to devour.] 
Eating both animal and vegetable^ 
tissue \zool.). 

omohyoid (o'mohl'oid) a. [Gk. 
omos, shoulder; hyoeides, Y-shaped.] 
Pert, shoulder and hyoid ; appl. a 
muscle (anat.}. 

omoideum (omoid'eum) n. [Gk. 
omos, shoulder ; eidos, shape.] 
The pterygoid bone in a Bird's 
skull (zoo/.). 

omosternum (o'mosteVnum) n. [Gk. 
omos, shoulder ; sternon, breast.] 
One of the elements of the Am- 
phibian sternum (zoo/.). 

omphalic (omfal'Ik) a. [Gk. omphalos, 
navel.] Pert, the umbilicus (anat.}. 

omphaloid (om'faloid) a. [Gk. 
omphalos, navel ; eidos, like.] Like 
a navel; having an umbilicus 

oinphaloidium (om'faioid'mm) n. 
[Gk. omphalos, navel ; eidos, like.] 
The scar at the hilum of a seed, 
or the hilum itself (dot.}. 

omphalomesaraic (8m'fal6m6s'- 
ara'lk), omphalomesenteric, which 

omphalomesenteric (om'falomSs'Sn- 
teVik) a. [Gk. omphalos, navel ; 
mesenteron, mid-gut.] Pert, um- 
bilicus and mesentery ; appl. veins, 
ducts (anat.}. 

onchosphere (Qng'kosfer) n. [Gk. 
ongkos, hook ; sphaira, a globe.] 
The larval stage of a tapeworm 
preceding the cysticercus stage ; 
the proscolex or six-hooked em- 
bryo stage of Cestoidea ; also 
oncosphere (zoo/.). 

ontocycle (on'tosi'kl) n. [Gk. on, 
being; kyklos, a circle.] Evolu- 
tion which in its later stages tends 
to produce forms exactly like those 
in the early stages (biol.}. 

ontogenesis (5n'tqj6n'gsls) n. [Gk. 
on, being ; genesis, descent.] The 
life-history of a single individual 

ontogenetic (on'toje'ne't'rk) a. [Gk. 
on, being ; genesis, descent.] Pert. 
ontogeny, or the development of 
the individual (biol.}. 

ontogeny (ontqj'finl) n. [Gk. on, 
being ; genos, birth.] Ontogenesis, 
which see. 

onychium (onik'Ium) n. [Gk. onyx, 
a nail.] The layer below the 
nail (anat.} ; a pulvillus ; in some 
spiders a special false articulation 
at the end of the tarsus to bear 
the claws (zoo/.). 

onychogenic (on'ikqjen'ik) a. [Gk. 
onyx, nail ; genos, offspring.] Cap- 
able of producing a nail or a nail- 
like substance ; appl. a material 
occurring in nail matrix and cells 
forming the fibrous substance and 
cuticula of hairs (phys.}. 

ooblastema (6'oblaste'ma) n. [Gk. 
oon, egg ; blastos, bud.] The egg 
after fertilization (zoo/.). 

oocyte (6'oslt) n. [Gk. oon, egg ; 
kytos, hollow.] An egg before the 
formation of the first polar body 
(emb.} ; in Protozoa a stage in the 
supposedly female cpnjugant before 
it prepares for fertilization (zoo/.). 

ooecium (oe'shium) n. [Gk. oon, egg ; 
oikos, house.] An ovicell (zoo/.). 

oogamete (o'og&met') . [Gk. 
oon, egg ; gamos, marriage.] An 
oosphere of Sporozoa (zoo/.). 

oogamous (oog'amus) a. [Gk, oon, 
egg ; gamos, marriage.] Having 
sexually differentiatedgametes (&?/.). 

oogenesis (6'6j6n'6sis) n. [Gk. oon, 
e SS > genesis, descent.] Forma- 
tion, development, and maturation 
of the egg (biol.). 

oogloea (6'ogle'a) n. [Gk. oon, egg ; 
gloia, glue.] Egg cement (zoo/.). 

oogonial (6'ogo'nial) a. [Gk. oon, 
egg ; gonos, descent.] Pert, the 

oogonium (o'ogo'nlum) n. [Gk. oon, 
egg ; gonos, offspring.] The female 
reproductive organ in certain Thal- 
lophytes (tot.) ; the mother egg-cell 

ooid (6'oid) a. [Gk. oon, egg ; eidos, 
form.] Egg-shaped. 




ookinesis (6'okine'sTs) n. [Gk. oon, 
egg ; kinein, to move.] The karyo- 
kinetic stages of the nucleus in the 
maturation and fertilization of the 
egg (biol.). 

ooklnete (o'okinef) n. [Gk. oon, 
egg ; kinein, to move.] The motile 
worm-shaped stage of the zygote in 
certain Protozoa (zool.}. 

oolemma (o'olem'a) n. [Gk. oon, 
egg ; lemma, a husk.] The vitel- 
line membrane of an egg (emb.}. 

oophore (6'ofor) n. [Gk. oon, egg ; 
pherein, to bear.] Oophyte, which 

oophoridium (o'oforid'mm) n. [Gk. 
oon, egg ; pherein, to bear.] The 
megasporangium in certain plants 

oophyte (o'ofit) n. [Gk. oon, egg ; 
phyton, a plant.] The sexual 
generation in such plants as the 
liverwort ; the gametophyte (bot.}. 

ooplasm (o'oplazm) n. [Gk. oon, egg ; 
plasma, something moulded.] The 
cytoplasm of an egg ; the yolk or 
cell substance of an egg (smb.}. 

oopod (6'opod) n. [Gk. oon, egg ; 
POUS, foot.] Any of the component 
parts of a sting or ovipositor (zool.}. 

oosperm (6'ospgrm) n. [Gk. oon, egg- ; .. 
sperma, seed.] A fertilized egg. 

oosphere (o'osfer) n. [Gk. oon, egg ; 
sphaira, globe.] An egg before fer* - 
tilization ; a female gamete (zool.}. 

oospore (6'ospor) n. [Gk. oon, egg ; 
sporos, seed.] The zygote or fer- 
tilized egg-cell (bot.} ; the encysted 
zygote in certain Protozoa (zool.}. 

oostegite (oos'tggit) n. [Gk. oon, egg ; 
stege, roof.] A plate-like structure 
on the basal portion of a thoracic 
limb in certain Crustaceans, which 
forms or helps to form a receptacle 
for the egg (zool.}. 

oostegopod (o'ostgg'opod) n. [Gk. 
oon, egg ; stege, roof ; pous, foot.] 
A thoracic foot bearing an oostegite 

ootheca (6'othe'ka) n. [Gk. oon, egg ; 
theke, a case.] A sporangium (hot.}; 
an egg-case, as in Insects (zool.}. 

ootocoid (oot'okoid) a. [Gk. oon, egg ; 
tokos, offspring ; cidos, form.] Giv- 
ing ^birth -to the young at a very 
early stagehand i then carrying them 

ootocous (oot'okiis) a. [Gk. oon, egg ; 
toko s, offspring.] Egg-laying (zool.}. 

ootype (6'otlp) n. [Gk. oon, egg ; 
type, place.] The part of the ovi- 
duct where the shell is formed ; 
the shell-gland of Turbellarians 
and Trematodes (zool.}. 

ooze (ooz) n. [A.S. ivos, juice.] A 
soft deposit found over large areas 
of the floor of the ocean. 

oozooid (6'ozo'oid) n. [Gk. oon, egg ; 
zoon, animal ; eidos, form.] Any 
individual developed from an egg. 

opercle (opeVkl) n. [L. operculum, a 
lid.] The posterior bone of a fish 
operculum (zool.}. 

operculate (opfir'kulat) a. [L. oper- 
culum, a lid.] Having a lid, as in 
the capsule of Mosses (bot.} ; having 
a covering for the gills, as in most 
Fishes (zool.}. 

operculiferous (opeYkulIf'e'rus) a. [L. 
operculum, a lid ; ferre, to bear.] 

operculiform (6p6r'kulif6rm') a. [L. 
operculum, a lid ; forma, shape.] 
Lid-like (bwl.}. 

operculigenous (opgr'kulij'gnus) a. 
[L. operculum, lid ; Gk. genos, off- 
spring.] Producing or forming a 
lid (zool.}. 

operculum (opeYkulum) n. [L. oper- 
culum, a lid.] A lid or flap, as in 
the capsules of Mosses (bot.} ; any 
of the convolutions covering the 
island of Reil (anat.} ; the lid-like 
structure seen in the Gastropods ; 
the movable plates in the shell of 
a Barnacle j the first pair of ab- 
dominal appendages in Limulus ; 
the gill-cover of Fishes ; the small 
plate covering the opening of a 
lung book in Spiders (zool.}. 

ophiopluteus (ofioploot'eus) n. [Gk. 
ophis, serpent ; L. pluteus, shed.] 
The pluteus larva of an Ophiuran 

ophryon (Sfrion) n. [Gk. ophrys, 
brow.] The point of junction of 
the median line of the face with 
a line across the narrowest part of 
the forehead (anat.}. 

opisthion (opis'thion) n. [Gk. opisthe, 
behind.] The median point of the 
posterior margin of the foramen 
magnum (anat}. 

opisthocoelous (opis'those'lus) a. [Gk. 




opisthe, behind ; koilos, hollow.] 
Having the centrum concave be- 
hind ; appl. vertebrae (anat.}. 

opisthodetic (opis'thodgfik) a. [Gk. 
opisthe, behind ; detos, bound.] 
Lying posterior to the beak ; appl. 
ligaments in some bivalve shells 

opisthoglossal(6pis'th6gl6s'al)0. [Gk. 
opisthe, behind ; glossa, tongue.] 
Having the tongue fixed in front, 
free behind (zool^. 

opisthognathous (opis'thognath'us) a. 
[Gk. opisthe, behind ; gnathos, jaw.] 
Having retreating jaws (zool.}. 

opisthotic (op'isthot'ik) a. [Gk. 
opisthe, behind ; ous, the ear.] 
Pert, the inferior posterior bony 
element of the otic capsule (zool.}. 

opisthure (5p'isthur / ) n. [Gk. opisthe, 
behind ; aura, a tail.] The pro- 
jecting tip of the vertebral column 

opponens (opo'nenz) a. [L. opponere, 
to oppose.] Pert, muscles which 
cause the digits to approach one 
another (anat.}. 

opposite (op'ozit) a. [L. opponere, to 
oppose.] Pert, leaves which are 
opposed, or placed opposite one 
another at the same level on 
opposite sides of the stem (bot.} 

opsonic (6pson'ik).0. [Gk. 
to cater.] Pert, or affected 
opsonin (phys}. 

opsonln (opso'nln) n. [Gk. 

to cater.] A constituent of blood 
which helps the phagocytes to de- 
stroy invading bacteria (phys.). 

optic (6p'tik) a. [Gk. opsis, sight.] 
Pert, vision. 

optic lobes, that part of the brain 
which supplies the eyes. 

optic thalami, see thalami. 

opticociliary (Sp'tlkc'sil'ian) a. [Gk. 
opsis, sight ; L. cilia, eyelashes.] 
Pert, optic and ciliary nerves (anat.). 

opticopupillary (Sp'tikopu'pilarl) a. 
[Gk. opsis, sight ; L. pupilla, pupil 
of eye.] Pert, optic nerve and pupil 
(anat.}. . 

optimum (op'tlmum) n. [L. optimus, 
best.] The most suitable degree 
of heat, etc., for the full develop- 
ment of the organism concerned 
(biol.) ; the point at which the best 
response can be obtained (phys.}. 

optocoel (8p'tosel) n. [Gk. opsis, 
sight ; koilos, hollow.] The cavity 
in the optic lobes of the brain 

optogram (Sp'togram) n. [Gk. opsis, 
sight 5 graphein, to write.] The 
image impressed on the retina by 
the action of light on the visual 
purple (phys.). 

ora serrata, the wavy border of the 
retina, where the nervous elements 
cease (anat.). 

oral (6'ral) a. [L. os, mouth.] Pert. 
or belonging to the mouth ; on the 
side on which the mouth lies. 

orbicular (orbik'ular) a. [Gk. orbis, an 
orb.] Appl. the eye muscles (anat.}. 

orbicularis (orblk'iila'ris) a. [L. orbis, 
an orb.] Appl. a muscle whose 
fibres surround an opening (anat.). 

orbiculate (orbik'ulat) a. [L. orbis, 
orb.] Nearly circular, in outline ; 
appl. leaves (bot.). 

orbit (or'blt) n. [L. orbita, a circuit.] 
The bony cavity in which the eye 
is situated (anat.) ; the skin round 
the eye of a bird ; the hollow in 
the arthropod cephalothorax in 
which the eye-stalk rises (zool.}. 

orbit*! (or'bital) a. [L. orbita, cir- 
-it.] Pert, the orbit. 

(or'bitoma'lar) a. [L. 
circuit ; mala, the cheek.] 
orbit and malar bone (anat}. 
*orbitonasal (drTrftona'zal) a. [L. 
orbita, circuit ; nasus, nose.] Pert. 
the orbit and the nasal portions of 
the adjoining bones (anat.). 

orbitosphenoid (6r / blt6sfe'noid) a. 
[L. orbita, circuit ; Gk. sphen, a 
wedge ; eidos, form.] Pert, paired 
cranial elements lying between 
presphenoid and frontal (zool.). 

order (dr'der) n. [L. ordo, order.] 
Any group of organisms closely 
allied, ranking between the family 
and the class (biol.). 

ordinate (o/dinat) a. [L. ordo, order.] 
Having the markings or orna- 
mentation arranged in rows (zool.). 

ordinatopunctate (or'dlna'topungTctat) 
a. \L. ordo, order ; punctum, 
a prick.] Indicating the serial 
presence of dots, etc. (zool.). 

Ordovician (dr'dOvIsh'an) a. [L. 
Ordovices, people of Wales.] Lower 
Silurian (pal.). 




organ (dr'gan) n. [Gk. organon, an 
implement.] Any part or structure 
of an organism adapted for a 
special purpose (biol.}. 

organ of Corti, see Corti's organ. 

organellae (dr'g&nei'e) n. plu. [Gk. 
organon, an instrument.] The 
various parts of a cell (cyt.). 

organic (organ'ik) a. [Gk. organon, 
an instrument] Pert., derived 
from, or showing the peculiarities 
of a living organism (biol.}. 

organiflc (o/ganTfik) a. [Gk. or- 
ganon, instrument ; L. facers, to 
make.] Producing an organism ; 
making an organized structure 

organism (dr'gamzm) n. [Gk. or- 
ganon, instrument.] Any living 
animal or plant ; anything capable 
of carrying on the processes of life 

organized (6r'ganTzd) a. [Gk. organon, 
instrument.] Exhibiting the char- 
acteristics of, or behaving like an 
organism (biol.}. 

organogen (organ'qjSn) n. [Gk. 
organon, instrument ; genos, off- 
spring.] Any of the four elements 
C., H., O., N. (phys.). 

organogenesis (6rgan'6j6n'Ssis) n. 
[Gk. organon, instrument ; genesis, 
descent.] The formation and de- 
velopment of organs (biol.}. 

organography (&r'ganog / rafi) n. 
[Gk. organon, instrument ; graphein, 
to write.] The description of the 
organs in any living organism 

organoleptic (6i / gan6l6p'tik) a. [Gk. 
organon, instrument ; lambanein, to 
take hold of.] Capable of being 
impressed, or of making an im- 
pression (phys.}. 

organonomy (or'ganon'oml) n. [Gk. 
organon, instrument ; nomos, law.] 
The laws that deal with life or 
living organisms (biol.}. 

organonymy (6r'ganon'imT) n. [Gk. 
organon, instrument ; onyma, name.] 
The nomenclature of organs (bwl.~). 

organophyly (6r'ganof'ili) n. [Gk. 
organon, instrument ; phylon, a 
tribe.] The phylogeny of organs 

nourish.] Pert, the formation and 
nourishment of organs (bwl.~). 

organule (oYganul) n. [Gk. organon, 
instrument] Any of the cells or 
elements of an organism (biol.~). 

orgasm (or'gazm) n. [Gk. organ, to 
swell.] Any immoderate excite- 
ment ; turgescence of any organism 

orientation (6'rienta'shun) n. [L. 
oriens, rising.] The alteration in 
position shown by various proto- 
plasmic bodies in the cell under 
various stimuli (phys.\ 

orifice (Sr'ifis) n. [L. os, mouth ; 
facere, to make.] A mouth or 
aperture ; the opening of a tube, 
duct, etc. 

original (drij'inal) a. [L. origo, 
origin.] Pert, the beginning ; 
appl. the wild species from which 
the cultivated have been derived 

ornis (6r'nis) n. [Gk. ornis, a bird.] 
The bird fauna of a region (zool.\ 

ornithic (ornith'ik) a. [Gk. amis, a 
bird.] Pert. Birds (pal^. 

ornithichnite (or'mthik'nlt) n. [Gk. 
ornis, bird ; ichnos, a tract.] The 
fossil track or foot-prints of a Bird 

ornithlne (dr'nithin) n. [Gk. ornis, 
bird.] An organic substance found 
in the excreta of Birds (phys.}. 

ornithocopros (or'nithokop'ros) . 
[Gk. ornis, bird ; kopros, dung.] 
The dung of Birds. 

Ornithogaea (6r / nlthoje'a) n. [Gk. 
ornis, bird ; gaia, land.] The zoo- 
raphical region which includes 
ew Zealand (zool.}. 


organotrophic (or'ganotrof'ik) a. [Gk. 
organon, instrument ; trephein, to 

ornithology (or'nithol'ojl) n. [Gk. 
ornis, bird ; logos, discourse.] The 
branch of Zoology dealing with 

ornithophilous (or'nithof'ilus) a. [Gk. 
ornis, bird ; philein,-\.Q love.] Bird- 
loving ; appl. flowers that are 
pollinated through the agency of 
Birds (bot.}._ 

oroanal (o'roa'nal) a. [L. os, mouth ; 
anus, anus.] Serving as mouth 
and anus (zool.~). 

oronasal (o'rona'zal) a. [L. os, 
mouth ; nasus, nose.] Pert, or 
designating the groove that con- 
nects the mouth and nose (zooL\ 




orthoenteric (or'thoe'n'te'rlk) a. 
[Gk. orthos, straight ; enteron, in- 
testine.] Having the alimentary 
canal stretched out along the 
ventral body surface ; appl. certain 
Tunicates (zool.). 

orthogenesis (or'thoje'n'e'sis) n. [Gk. 
orthos, straight ; genesis, descent.] 
Variation which, irrespective of 
natural selection or external forces, 
gradually produces a new and dis- 
tinct type (btol.). 

orthopterous (6rth8p'te"rus) a. [Gk. 
orthos, straight ; pteron, wing.] 
Having straight folded posterior 
wings (zoo/."). 

orthospermous (or'thospeVmus) a. 
[Gk. orthos, straight ; sperma, seed.] 
With straight seeds (hot.). 

orthostichous (6rth6s'tlkus) a. [Gk. 
orthos, straight ; stichos, a row.] 
Appl. a fin skeleton when the peri- 
pheral somactids are parallel as in 
Cladoselache (pal.). 

orthostichy (orthos'Hk!) n. [Gk. 
orthos, straight ;_ stichos, a row.] 
The vertical line on which a row 
of leaves or scales is found ; the 
arrangement of the leaves or scales 
in this row (bot.). 

orthotriaene (6r'th6tri'en) n. [Gk. 
orthos, straight ; triaina, a trident.] 
A triaene with cladi directed out- 
wards at right angles to the shaft 

orthotropism (orthot'ropizm) n. [Gk. 
orthos, straight ; trope, a turning.] 
Growth in a vertical line (hot.*). 

orthotropous (orthSr/ropus) a. [Gk. 
orthos, straight ; trope, a turning.] 
Having the chalaza, hilum, and 
micropyle in a straight line ; appl. 
ovules (bot.). 

os (6s) n. [L. os, a bone.] A bone. 

osculant (os'kulant) a. [L. osculans, 
kissing.] Closely adherent ; inter- 
mediate in character between two 
groups (btol.). 

oscular (os'kular) a. [L. osculum, a 
small mouth.] Pert, an osculum. 

osculate (os'kulat) v. [L. osculare, to 
kiss.] To have characters inter- 
mediate between two groups (biol.). 
osculiferous (6s'kullf6rus) a. [L. 
osculum, a small mouth ; ferre, to 
bear.] Having oscula (zool.). 
osculum (Ss'kulum) n. [L. osculum, 

a small mouth.] An excurrent open- 
ing in a Sponge (zool.). 

osmeterium (os'mgte'rium) n. [Gk. 
osme, smell.] A forked protrusible 
organ borne on the first thoracic 
segment of the larva of many 
butterflies, and emitting an offen- 
sive smell (zool.). 

osmosis (osmo'sis) n. [Gk. othein, to 
push.] A diffusion which takes 
place between two miscible fluids 
through a permeable membrane 

osmotic (SsmSt'ik) a. [Gk. othein, to 
push.] Pert, osmosis (phys.). 

osphradium (osfra'dium) n. [Gk. 
osphradion, strong scent.] A sense 
organ associated with the visceral 
ganglia in Molluscs, olfactory in 
function (zool.). 

O88& triquetra, the Wormian bones 

ossein <(5s'eTn) n. [L. osseus, bony.] 
The organic base of bone (phys.). 

osseous (os'eus) a. [L. osseus, bony.] 
Composed of or resembling bone 

ossicle (fis'ikl) n. [L. os, bone.] Any 
small bone ; one of those in the 
sclerotic ; one of those in the 
gastric mill of Crustacea ; a plate 
of a sea-urchin's test (zool.). 

ossicular (Sslk'ular) a. [L. os, bone.] 
Pert, ossicles. 

ossiculum (osik'ulum) n. [L. os, 
bone.] An ossicle ; a lithodesma 
(zool.} ; a pyrene (bot.). 

ossification (Sslfika'shun) n. [L. 
os, bone ; facere, to make.] The 
formation of bone ; the replace- 
ment of cartilage by bone (anat.). 

ossify (os'tfi) v. [L. os, bone ; fieri, 
to become.] To change to bone 

osteoblast (Ss'teoblast) n. [Gk. 
osteon, bone ; blastos, bud.] A 
bone-forming cell (smb.). 

osteoclast (Ss'teoklast) n. [Gk. osteon, 
a bone ; klan, to break.] A cell 
which absorbs or breaks up bony 
tissue (entb.). 

osteocomma (os'teok8m'a) n. [Gk. 
osteon, bone ; komma, piece.] A 
segment of the vertebral skeleton 

osteocranium (6s'teokra'nlum) . 
[Gk. osteon, bone ; kranion, skull.] 




The bony skull as distinguished 
from the cartilaginous or chondro- 
cranium (zool.}. 

osteodentine (os'teoden'tm) n. [Gk. 
osteon, bone ; L. dens, a tooth.] 
A variety of dentine which closely 
approaches bone in structure (zool.}. 

osteodermis (os'teodeYmis) n. [Gk. 
osteon, bone ; derma, skin.] A 
dermis which is more or less 
ossified ; a bony dermal plate 

osteogen (os'teqje'n') n. [Gk. osteon, 
bone ; genos, offspring.] The tissue 
which alters and forms bone (phys.}. 

osteogenesis ((8s'teoj6n'6sis) n. [Gk. 
osteon, bone ; genesis, descent.] 
Bone formation (emb.}. 

osteogenetic (os'teqje'ne't'ik) a. [Gk. 
osteon, bone ; genesis, descent.] 
Pert, or causing the formation of 
bone (emb.}. 

osteogenic (os'teojgn'lk) a. [Gk. 
osteon, bone ; genos, offspring.] 
Bone-producing (phys.}. 

osteoid (5s'teoid) a. [Gk. osteon, 
bone ; eidos, form.] Bone - like 

osteology (os'teol'oji) n. [Gk. osteon, 
bone ; logos, discourse.] That part 
of anatomy that deals with the 
structure, nature, and development 
of bones. 

osteoplastic (5s'teoplas'tik) a. [Gk. 
osteon, bone ; plastos, moulded.] 
Producing bone ; appl. certain cells 

osteoporosis (Ss'teoporo'sTs) n. [Gk. 
osteon, bone ; poros, a pore.] The 
absorption of bone, resulting in a 
porous structure (phys.}. 

ostiolar (os'tiolar) a. [L. ostiolum, a 
little door.] Pert, an ostiole (biol.}. 

ostiolate (os'tiolat) a. [L. ostiolum, 
little door.] Provided with ostioles 

ostiole (os'tlol) n. [L. ostiolum, little 
door.] The opening of a con- 
ceptacle, of a perithecium, of a 
stoma, of an anther sac (bot.} ; the 
inhalent aperture of a Sponge (zool.}. 

ostium (os'tium) n., ostia (os'tia) plu. 
[L. ostium, a door.] Any mouth- 
like opening ; the openings of the 
Fallopian tubes ; the opening in 
the crustacean heart by means of 
which the blood enters the heart 

from the pericardium ; the opening 
from flagellate canal into para- 
gastric cavity in Sponges (zool.}. 

otic (o'tik) a. [Gk. ous, the ear.] Pert. 
the region of the auditory capsule 

otidium (otid'mm) n. [Gk. ous, ear.] 
The otocyst of a Mollusc (zool.}. 

otoconium (6'toko'nium) n. [Gk. ous, 
ear ; konia, grain of sand.] One of 
the minute particles found in the 
internal ear (anat.}. 

otocrypt (6'tokript) n. [Gk. ous, ear ; 
kryptos, hidden.] An open invagina- 
tion of the integument of the foot 
in certain Molluscs (zool.}. 

otocyst (o'tosist) n. [Gk. ous, ear ; 
kystis, bladder.] A sac containing 
fluid and otoliths, supposed to be 
auditory (zool.}. 

otolith (6'tolith) n. [Gk. ous, ear; 
lithos, stone.] The calcareous par- 
ticle or plate-like structure found 
in the ear or the auditory organ of 
many animals (zool.}. 

otoporpae (o'topor'pe) n. plu. [Gk. 
ous, ear ; porpe, a brooch.] Stripes 
of cnidoblasts on the exumbrella of 
Hydromedusae (zool.}. 

oval (6'val) a. [L. ovum, egg.] Egg- 
shaped ; pert, an egg. 

ovalbuinin (o'valbu'min) n. [L. ovum, 
egg ; albumen, white of egg.] The 
chief constituent of white of egg 

ovarian (ova'riSn) a. [L. ovanum, 
an ovary.] Pert, an ovary. 

ovariole (ovar'iol) n. [L. ovarium, 
ovary.] The ovarian tube of an 
Insect ; the tubes which together 
form the ovary (zool.}. 

ovarium (ova'rium) n. [L. ovarium, 
ovary.] An ovary. 

ovary (6'vari) n. [L. ovarium, ovary.] 
The essential female reproductive 
organ (zool.} ; an enlarged portion 
of the pistil or gynoecium (bot.}. 

ovate (6'vat) a. [L. ovum, egg.] 

ovate-acuminate, appl. an ovate 
lamina with a very sharp point ; 
appl. leaves (bot.}. 

ovate-ellipsoidal, ovate, approach- 
ing ellipsoid ; appl. leaves (bot.}. 

ovate-lanceolate, having a form of 
lamina intermediate between ovate 
and lanceolate (bot.}. 




ovate -oblong, having an oblong 
lamina with one end narrower than 
the other (bot.). 

ovenchyma (ovgng'klma) n. [L. 
ovum, egg ; Gk. engchyma, in- 
fusion.] A connective tissue with 
ovoid-shaped cells (smb.}. 

ovicell (o'vIsSl) n. [L. ovum, egg ; 
cellula, a cell.] A dilatation of the 
zooecium, serving as a brood pouch 

oviduct (6'vldukt) n. [L. ovum, egg ; 
ducere, to lead.] The tube which 
carries the eggs from the ovary to 
the exterior ; the Miillerian duct ; 
the tube may or may not be 
attached to the ovary (zool.). 

oviferous (ovif'e'rus) a. [L. ovum, 
egg ; ferre, to carry.] Serving to 
carry the eggs (zool.). 

oviform (o'viform) a. [L. ovum, Qgg ; 
forma, shape.] Egg-shaped. 

oviparity (6'vipar'itl) n. [L. ovum, 
egg ; parere, to bring forth.] Con- 
dition of being oviparous (zoo/.). 

oviparous (ovip'arus) a. [L. ovum, 
egg ; parere, to bring forth.] Pro- 
ducing eggs : egg-laying ; cf. vivi- 
parous (zool.). 

oviposit (6'vipoz'it) v. [L. ovum, 
egg ; ponere, to place.] To lay 
eggs ; appl. Insects (zool.). 

ovipositor (o'vipoz'itSr) n. [L. ovum, 
egg ; ponere, to place.] A special- 
ized structure in Insects for placing 
the eggs in a suitable place ; a 
tubular extension of the genital 
orifice in Fishes (zool.). 

ovisac (6'visak) n. [L. ovum, egg ; 
saccus, a bag.] An egg-capsule 

ovism (6'vizm) n. [L. OVUM, egg.] 
The theory held by the Ovists that 
the egg contained the germ with 
the germs of all future generations 
within it (biol.). 

ovist (6'vTst) n. [L. ovum, egg.] A 
supporter of the Ovism theory (biol.). 

ovocentre (o'vosSn'ter) n. [L. ovum, 
egg ; centrum, a centre.] The egg- 
centrosome during fertilization 

ovogenesis (o'vbjen'e'sis) n. [L. ovum, 
egg ; Gk.. genesis, descent.] Oogen- 
esis, which see. 

ovoid (o'void) a. [L. ovum, egg ; Gk. 
cidos, form.] Egg-shaped. 

ovomucoid (o'vomu'koid) n. [L. 
ovum, egg ; mucus, mucus ; Gk. 
eidos, form.] A mucoid found in 
eggs (pkys.). 

ovotestis (o'votgs'tis) n. [L. ovum, 
egg; testis, testicle.] The her- 
maphroditic reproductive gland of 
certain Gastropods (zoo/.). 

ovoviviparous (6'vovivip'arus) a. [L. 
ovum, egg ; vivus, living ; parere, 
to bring forth.] Pert, forms which 
produce an egg with a definite 
shell, which yet hatch out internally 

ovulate (ov'ulat) a. [L. ovum, egg.] 
Containing an egg or ovule (hot., 

ovule (6'vul) n. [L. ovum, egg.] The 
megasporangium of a seed-plant 
(bot.) ; any small egg or egg-like 
structure (zool.). 

ovuliferous (o'vullfgrus) a. [L. ovum, 
egg ; ferre, to carry.] Ovule- 
producing ; containing ovules (bot.). 

ovuliferous scales, stout scales, 
each bearing two ovules, developed 
on bract scales (bot.). 

ovum (6'vum) n. [L. ovum, egg.] 
A female germ cell (biol.). 

oxea (ok'sea) n. [Gk. oxys, sharp.] 
A sponge spicule, rod-shaped and 
sharp at both ends (zool.). 

oxeote (ok'seot) a. [Gk. oxys, sharp.] 
Like an oxea ; in the iform of a 
simple rod ; appl. sponge spicules 

oxidize, oxydize. 

oxyaster (6k'sias'ter) n. [Gk. oxys, 
sharp ; aster, a star.] A stellate 
sponge spicule with sharp-pointed 
rays (zool.). 

oxychromatin (ok'slkro'mattn) . 
[Gk. oxys, sharp ; chroma, colour.] 
Linin (emb.). 

oxydactyl (ok'stdak'tll) a. [Gk. oxys, 
sharp ; daktylos, a finger.] Havmg 
slender tapering digits (zool.). 

oxydase (6k stdas) n. [Gk. oxys, sour.] 
An enzyme which promotes oxy- 
dation (phys.). 

oxydiact (ok'sldfakt) a. [Gk. oxys, 
sharp ; di, two ; aktis, ray.] Having 
three rays of which only two are 
fully developed ; appl. sponge 
spicules (zool.). 

oxydize (ok'sidlz) v. [Gk. oxys, acid.] 
To combine with more oxygen ; to 




increase the oxygen content of the 
blood (phys.). A 

oxygnathous (ok'signath'us) a. [Gk. 
oxys, sharp ; gnathos, jaw.] Having 
more or less sharp jaws (zool.}. 

oxyhaemoglobin (ok'sihe'moglo'bin) 
n. [Gk. oxys, acid ; haima, blood ; 
L. globus, a globe.] Haemoglobin 
combined with oxygen, as found in 
arterial blood (phys.}. 

oxyhexactine (ok'sihSksak'tin) n. 
[Gk. oxys, sharp ; hex, six ; aktis, 
ray.] A hexactine with rays ending 
in sharp points (zool.). 

oxyhexaster (ok'siheksas'ter) n. [Gk. 
oxys, sharp ; hex, six ; aster, star.] 
A hexaster with rays ending in 
sharp points (zool.}. 

oxyntic (oksm'tik) a. [Gk. oxyein, 
to make acid.] Secreting acid ; 
appl. cells, glands (phys.~). 

oxytropism (oksit'roplzm) n. [Gk. 
oxys, acid ; trope, a turning.] The 
tendency of numerous organisms 
to be attracted by oxygen (phys.}. 

oxytylote (ok'sitl'lot) n. [Gk. oxys, 
sharp ; tylos, a knob.] A slender, 
straight sponge spicule, sharp at 
one end, knobbed at the other 

P,, denoting the first parental 
generation, P 2 the grandparents, 
etc., in the law of Mendel. See Fj. 

Pacinian bodies or corpuscles, 
distal nerve-endings, consisting of 
lamellated connective-tissue capsule 
with a core of nucleated proto- 
plasmic cells containing the ramifi- 
cations of a single medullated 
nerve-fibre (anaf.). 

paedogenesis (pe'dojSn'esis) n. [Gk. 
pais, child ; genesis, descent.] 
Breeding while still in the young 
or larval state, as Axolotl, certain 
Diptera (zool.}. 

paired flns, the pectoral and pelvic 
fins of fishes ; dorsal, anal, and 
caudal fins are unpaired. 

Palaeobotany (pal'eobot'anl) n. [Gk. 
palaios, ancient ; botane, a plant.] 
The botany of fossil plants or plant 

palaeogenetic (pal'eojenet'Ik) a. [Gk. 
palaios, ancient ; genesis, descent.] 
Appl. atavistic features fully de- 
veloped, which are usually char- 
acteristically embryonic (biol.). 

Palaeontology (pal'eontol'oji) n. [Gk. 
palaios, ancient ; ons, being ; logos, 
discourse.] The science of past 
organic life based on fossils and 
fossil impressions. 

Palaeozoic (pal'edzo'ik) a. [Gk.palaios, 
ancient ; zoon, animal.] Appl. the 
Primary or earliest of the three 
groups of rock-systems (pal.}. 

Palaeozoology (pal'eozSol'bji) n. [Gk. 
palaios, ancient ; zoon, animal ; 
logos, discourse.] The zoology of 
fossil animals and animal im- 

palama (pal'ama) n. [Gk. palame, 
th,e palm.] Foot-webbing of aquatic 

palamate, palmate. 

palatal (pal'atal) a. [L. palatum, 
palate.] Pert, the palate ; palatine ; 
appl. bone, sinus, etc. (anaf.). 

palate (pal'at) n. [L. palatum, 
palate.] The roof of the mouth 
(anaf.) ; an insect epipharynx 
(zool.} ; a projection of the lower 
lip of a personate corolla (&?/.). 

palatine (pal'atin) a. [L. palatum, 
palate.] Pert, or in the region of 
the palate ; appl. artery, bone, 
foramen, etc. (anaf.). 

palatoglossal (pal'atoglos'al) a. [L. 
palatum, palate ; Gk. glossa, tongue.] 
Pert, palate and tongue ; appl. a 
muscle (anaf.). 

palatonasal (pal'atona'zal) a. [L. 
palatum, palate ; nasus, nose.] 
Pert, palate and nose (anaf.). 

palatopharyngeal (pal'atofarin'jeal) a. 
[L. palatum, palate ; Gk. pharyngx, 
pharynx.] In the region of palate 
and pharynx ; appl. a muscle 

palatopterygoid (pal'atopter'igoid) a. 
[L. palatum, palate ; Gk. pterygion, 
little wing ; eidos, resemblance.] 
In the region of or pert, palate and 
pterygoid (anaf.). 

palatoquadrate (pal'at6'kw6d'ra.t) a. 
[L. palatum, palate ; quadrat us, 
squared.] Connecting palatine and 
quadrate ; appl. the dorsal cartilage 
of the mandibular arch (anaf.). 




palea (pa'lea) n. [L. palea, chaff.] 
One of little bracts on the florets 
of Compositae^ (&?/.). 

paleaceous (palea'shus) a. [L. palea, 
chaff.] Appl. a capitulum furnished 
with small scaly bracts or paleae 

paliform (pa'liform) a. [L. palus, a 
stake ; forma, shape.] Like an 
upright stake. 

palingenesis (pal'injfin'gsis) n. [Gk. 
palin, anew ; genesis, descent.] 
Abrupt metamorphosis ; the re- 
birth of ancestral characters (bio/.). 

palisade tissue, the general ground 
tissue of many foliage leaves, 
so called from the palisade-like 
arrangement of their elongated 
cells (bot.). 

pallet (pal'et) n. [L. pala, a spade.] 
A shelly plate on a bivalve siphon 

pallial (pal'ial) a. [L. pallium, 
mantle.] Pert, the molluscan 
pallium or mantle ; appl. line, 
groove, sinus, muscles (zoo!.}. 

palliate (pal'iat) a. [L. pallium, 
mantle.] Having a mantle or 
similar structure (zoo/.). 

palliopedal (pal'ioped'al) a. [L. 
pallium, mantle ; pes, foot.] Pert. 
molluscan mantle and foot. 

pallium (pal'mm) n. [L. pallium, 
mantle.] A mollusc or brachiopod 
mantle ; a portion of the cerebral 
wall (zoo/.). 

palmar (pal'mar) a. [L. palma, palm 
of the hand.] Pert, the palm of the 
hand ; appl. aponeurosis, nerve, 
muscle (anat.). 

palmaria (palma'ria) n. plu. [L. 
palmaris, pert, the palm.] The 
third brachials of Crinoids (zoo/.). 

palmate (pal'mat) a. [L. palma, palm 
of the hand.] Appl. leaves divided 
into lobes arising from a common 
centre (pot.) ; having anterior toes 
webbed, as in most aquatic Birds 

palmatifld (palmat'ifid) a. [L.^a/ma, 
palm of the hand \findere, to cleave.] 
Appl. leaves divided into lobes to 
about the middle, at acute angles 
to each other (bot.). 

palmatilobate (palmat'llo'bat) a. [L. 
palma, palm ; lobus, a lobe.] Pal- 
mate with rounded lobes and 

divisions half-way to the base 

palmatipartite (palmat'ipir'tlt) a. 
[L. palma, palm ;partitus, divided.] 
Palmate with the divisions more 
than half-way to the base (bot.). 

palmatisect (palmat'Isgkt) a. [L. 
palma, palm ; sectus, cut.] Palmate 
with the divisions nearly to -the 
base (bot.). 

palmella (palmeTa) n. [Gk. palmos, 
a quivering.] A stage of certain 
Algae, consisting of groups of 
rounded cells in a jelly-like mass 

palmitin (pal'mitin) n. [Gk. palma, 
palm-tree.] A compound of fatty 
acid and glycerine found in adi- 
pose tissue (phys!). 

palmula (pal'mula) n. [L. palma, 
palm.] A terminal lobe or process 
between the paired claws of insect 
feet (zoo/.). 

palp, see palpus. 

palpacle (pal'pakl) n. [L. palpare, 
to feel.] The tentacle of a dactylo- 
zooid or palpon of Siphonophora 

palpal (pal'pal) a. [L. palpare, to 
stroke.] Pert, a palpus. 

palpate (pal'pat) a. [L. palpare, to 
stroke.] Provided with a palpus 
or palpi (zoo/.). 

palpebra (pal'pSbra) n. [L. palpebra, 
an eyelid.] An eyelid. 

palpebral (pal'pfcbral) a. [L. palpebra, 
an eyelid.] Pert, the eyelids ; appl. 
arteries, ligament, nerves (anat.) ; 
appl. a lobe or buttress on which 
the eye of Trilobites rests (zoo/.). 

palpifer (pal'plfgr) n. [L. palpare, to 
feel ; ferre, to carry.] A maxilla 
lobe bearing the palpus of Insects 

palpiform (pal'plf6rm) a. [L. pal- 
pare, to feel ; forma, shape.] Re- 
sembling a palpus or insect-feeler 

palpiger (pal'pljgr) n. [L. palpare, 
to feel ; gerere, to bear.] The 
support of a labial palpus in In- 
sects (zoo/.). 

palpocil (pal'posil) n. [L. palpare, to 
touch ; cilium, a lashj A stiff sen- 
sory filament attached to the sense 
cells of Hydromedusae (zoo/.). 

palpon (pal'pon) /;. [L. palpare, to 




feel.] A hydrocyst or dactylozooid 
of Siphonophores (zool.). 

palpulus (pal'pulus) n. [L. palpare, 
to feel.] A small palpus or feeler. 

palpus (pal'pus) #., palpi (pafpL 
pal'pe) plu. [L. palpare, to feel.] 
The labial feelers of Insects ; sen- 
sory appendages on the prostomium 
of polychaet worms, on mandibles 
of Crustacea, etc. (zool.). 

paludicole (palu'dikol) a. [L. palus, 
a marsh ; colere, to inhabit.] Living 
in ponds and streams. 

palule (pal'ul) n. [L. palus, a stake.] 
An unattached calcareous process 
of Corals ; a small palus (zoo/.). 

palus (pa'lus) n., pali (pa'H, pal'e) 
plu. [L. palus, a stake.] A series 
of small pillars projecting upwards 
from the theca-base towards the 
stomodaeum of madrepore Corals 

pampiniform (pampm'iform) a. [L. 
pampinus, a tendril ; forma, shape.] 
Tendril-like (biol.) ; appl. a con- 
voluted vein plexus of the sper- 
matic cord (anat.). 

pancreas (pan'kreas) n. [Gk. pan, all ; 
kreas, flesh.] A compound racemose 
gland at the posterior abdominal 
wall of most vertebrates. 

pancreatic (pankreat'Ik) a. [Gk. pan, 
all ; kreas, flesh.] Pert, the pan- 
creas ; appl. artery, duct, vein 

pancreaticoduodenal, pert, pan- 
creas and duodenum ; appl. artery, 
glands, veins (anat.}. 

panduriform (pandu'riform) a. [L. 
pandura, a three - stringed lute ; 
forma, shape.] Fiddle - shaped ; 
appl. leaves (dot.}. 

pangamic (pangam'ik) a. [Gk. pan, 
all ; gamos, union.] Appl. indis- 
criminate mating. 

pangen (pan'je'n) n. [Gk. pan, all ; 
genos, offspring.] Biophore ; see 
hypothetical units. 

pangenesis (panjeVesis) n. [Gk. 
pan, all ; genesis, descent.] The 
gemmule theory, that hereditary 
characteristics are carried by germs 
from individual body cells (biol.). 

panicle (pan'lkl) n. [L. panicula, a 
tuft on plants.] A tuft or bunch of 
flowers or seeds, close or scattered ; 
a compound raceme (dot.). 

paniculate (pamk'ulat) a. [L. pani- 
cula, a tuft] Having the flowers 
arranged in panicles (oof.). 

panmeristic (pan'meris'tik) a. [Gk. 
pan, all ; meros, part.] Appl. an 
ultimate protoplasmic structure of 
independent units (biol.). 

panmixia (panmlk'sta) n. [Gk. pan, 
all ; mixis, a mixing.] Indiscrimi- 
nate interbreeding consequent on 
suspension of the influence of 
natural selection. 

pansporoblast (panspo'roblast) n. 
[Gk.pan, all ; sporos, seed ; blastos, 
bud.] A cell-complex of Neosporidia 
producing sporoblasts and spores ; 
an archespore (zool.). 

papilionaceous (papTl'iona'shus) a. 
[L. papilio, a butterfly.] Re- 
sembling a butterfly ; appl. a five- 
petal corolla, one enlarged posterior, 
two united anterior forming a keel, 
and two lateral, the wings or alae 

papilla (papil'a) n. [L. papilla, a 
pimple.] A glandular hair with 
one secreting cell above the epi- 
dermis level (bot.) ; an accessory 
adhesive organ with retractile tip, 
of some Trematodes ; a conical 
dermal structure on Birds, the 
beginning of a feather (zooL) ; one 
of various small projections of the 
corium of the tongue, and eminences 
on the skin (anat.). 

papillary (papll'ari) a. [L. papilla, 
a pimple.J Pert, papillae ; appl. a 
dermal layer with papillae (anat.). 

papillate (papll'at) a. [L. papilla, a 
pimple.] Covered by papillae ; 
papillose ; like a papilla (biol.) ; 
appl. petals with external cells 
projecting slightly above the sur- 
face (bot.). 

papilliform (papTl'iform) a. [L. 
papilla, a pimple ; forma, shape.] 
Like a papilla in shape. 

papillose, papillate. 

pappiferous (paplf'e'rus) a. [Gk. 
pappos, an old man ; L. ferre, to 
carry.] Pappus-bearing (bot.). 

pappose (pap'os, papSs') a. [Gk. 
pappos, an old man.] Having the 
limb of the calyx developed as a 
tuft of hairs or bristles ; downy, or 
covered with feathery processes 




pappus (pap'us) n. [Gk. pappos, an 
old man.] A circle or tuft of 
bristles, hairs, or feathery processes 
in place of the limb of a calyx 

papulae (pap'ule) n. plu. [L. papula, 
a pimple.] Dermal gills ; the soft 
skin of Asteroids raised up into 
finger-like processes with respira- 
tory function (zool.). 

papyraceous (papira'shus) a. [L. 
papyrus, the papyrus-tree.] Of 
papery texture (dot.}. 

parabasal (paraba'sal) a. [Gk. para, 
beside ; basis, base.] Appl. a 
striated apparatus surrounding the 
calyx of certain Protozoa (zool.}. 

parabasalia (par'abasa'lia) n. plu. 
[Gk. para, beside ; basis, base.] 
The basalia of Crinoids when a 
circlet of perradial infrabasalia 
occurs beneath them (zool.). 

parablast (par'ablast) n. [Gk. para, 
beside ; blastos, bud.] The yolk 
of meroblastic eggs ; appl. the large 
nuclei of cells laden with yolk- 
granules, in the development of 
higher Mammals (smb.), 

parabranchia (parabrang'kla) n. [Gk. 
para, beside ; brangchia, gills.] A 
much plumed mollusc osphradium 
or organ of smell (zool.}. 

parabronchi (parabrong'kl) n. plu. 
[Gk. para, beside ; brongchos, wind- 
pipe.] The tertiary lung tubes of 
Birds, their terminations being em- 
bedded in the lung mesenchyme 

paracentral (parasgn'tral) a. [Gk. 
para, beside j L. centrum, centre.] 
Situated at or near the centre ; 
appl. lobule, gyrus, fissure (anat.). 

parachordal (parakor'dal) a. [Gk. 
para, beside ; chords, a cord.] Appl. 
paired horizontal cartilage plates 
formed on each side of the chon- 
drocranium (emb.). 

parachromatin (parakro'matin) ;/. 
[Gk. para, beside ; chroma, colour.] 
Achromatic nuclear substance giv- 
ing rise to spindle-fibres (cyt.). 

parachute (par'ashoot) n. [L.parare, 
to prepare ; F. chute, a fall.] A 
special structure, such as an aril, 
a caruncle, a wing, of seeds en- 
abling them to be wafted away, and 
so aiding in dispersal (bot.). 

paracme (parak'me) n. [Gk. parakme, 
decadence.] The decline of a 
species or race after reaching the 
highest point of development 

paracoel (pSr'asel) n. [Gk. para, 
beside ; koilos, hollow.] The lateral 
ventricle, or cavity of the cerebral 
hemisphere (ana/.). 

paracondyloid (parakon'dlloid) a. 
\Gk.para, beside ; kondylos, a knob ; 
eidos, resemblance.] Appl. a pro- 
cess of the occipital occurring 
beside the condyles of some mam- 
mals (zool.}. 

paracone (par'akon) n. [Gk. para, 
beside ; konos, a cone.] The 
antero-external cusp of an upper 
molar tooth. 

paraconid (parako'nid) n. [Gk. para, 
beside ; konos, cone.] The antero- 
internal cusp of a lower molar 

paracorolla (par'akorSl'a) n. [Gk. 
para, beside ; L. corolla, a small 
crown.] A corolla appendage (dot.). 

paracyst (par'aslst) n. [Gk. para, 
beside ; kystis, a bladder.] The 
antheridium of Pyronema (bot.}. 

paraderm (par'aderm) n. [Gk. para, 
beside ; derma, skin.] The delicate 
limiting membrane of a pronymph 

paradidymis (paradld'imis) n. [Gk. 
para, beside ; didymos, a testicle.] 
A small collection of convoluted 
tubules anterior to the lower part 
of the spermatic cord (ana/.). 

paraflbula (paraf Ib'ula) n. [Gk. para, 
beside ; L. fibula, a buckle.] An 
accessory element outside the fibula 
at its proximal end, seen in some 
Lacertilia and young Marsupials 

paraflagellum (paraflajeTum) n. [Gk. 
Para, beside ; L. fiagellum, a whip.] 
A subsidiary flagellum (zool.). 

paraganglia (par'agang'glla) . flu. 
[Gk. para, beside ; ganglion, swell- 
ing.] Scattered remains or rudi- 
ments of ganglia left along the 
aorta when the suprarenal ganglion 
has been formed (phys.). 

paragaster (paragas'te'r) n. [Gk. 
para, beside ; gasler, stomach.] 
A central cavity of Heterocoela into 
which gastric ostia open (zool.). 




paragastric (paragas'trik) a. [Gk. 

para, beside ; gaster, stomach.] 

Pert, a paragaster ; appl. passages 

! or cavities in the branches of a 

- Sponge ; appl. paired blind canals 
I from the infundibulum to the oral 

f^cone of Ctenophores (zool.}. 

paragastrula (paragas'troola) n. [Gk. 
para, beside ; gaster, stomach.] The 
stage of the amphiblastula of a 
Sponge when the flagellated cells 
are invaginated into the dome of 
rounded cells (zool.}._ 

paragenesia (parajene'sia) n. [Gk. 
para, beside ; genesis, descent.] 
Hybrids' fertility with the parent 
species but not inter se (biol.}. 

paraglossa (paraglos'a) n. [Gk.para, 
beside ; glossa, tongue.] A process 
on each side of the ligula of Insects 

paraglycogen (paragll'kojen) n. [Gk. 
para, beside ; glykos, sweet ; genos, 
production.] Reserve food-material 
stored in protoplasm-grains of 
Gregarines (zool.}. 

paragnatha (paragna'tha) n. plu. 
[Gk. para, beside ; gnathos, jaw.] 
Paired, delicate, unjointed processes 
between maxilla and mandible of 
certain Crustacea (zool}. 

paragnathous (par'agnath'us) a. 
[Gk. para, beside ; gnathos, jaw.] 
With mandibles of equal length ; 
appl. Birds. 

paraheliotropism (par'ah eliot'ropizm) 
n. [Gk. para, beside ; helios, sun ; 
trope, a turning.] Tendency of 
plants to turn the edges of their 
leaves to too brilliant an illumina- 
tion to save their surfaces (hot.}. 

parahormone (par'ah&r'mon) n. [Gk. 
para, beside ; ormao, I arouse to 
activity.] A substance which acts 
like a hormone but is a product of 
the ordinary metabolism of cells ; 
e.g., the sensibility of a nerve to 
carbon dioxide (p^hys.}. 

paralinin (parall'nin) n. [Gk. para, 
beside; L. linum, a linen thread.] 
Nuclear ground-substance (cyt.}. 

parallelinervate, parallelodrome, 
appl. leaves with veins or nerves 
parallel (bot.}. 

paramastigote (paramas'tigot) a. 
[Gk. para, beside ; mastis, a whip.] 
Having one long principal flagellum 

and a short accessory one, as cer- 
tain Mastigophora (zool.}. 

paramastoid (paramas'toid) a. [Gk. 
para, beside ; mastos, breast ; eidos, 
resemblance.] Beside the mastoid ; 
appl. the two paroccipital processes 
of the exoccipitals (zool.}. 

paramere (par'amer) n. [Gk. para, 
beside ; meros, part.] Half of a bi- 
laterally symmetrical structure. 

paraxnetrium (paramet'rium) n. 
[Gk. para, beside ; metra, uterus.] 
Fibrous tissue partly surrounding 
the uterus (anat.}. 

paramitome (paraml'tom) n. [Gk. 
para, beside ; mitos, a thread.] 
The interfilar substance of proto- 
plasm (cyt.}. 

paramylum (parami'lum) n. [Gk. 
para, beside ; amylon, starch.J A 
substance allied to starch, occur- 
ring in Protozoa (phys.}. 

paranephric (paranef'rik) a. [Gk. 
para, beside ; nephros, kidney.] 
Beside the kidney ; appl. a fatty 
body behind the renal fascia (anat.}. 

paranephros (paranefros) n. [Gk. 
para, beside ; nephros, kidney.] 
An adrenal body. 

paranuclein (paranu'klem) n. [Gk. 
para, beside ; L. nucleus, a kernel.] 
The substance of a true nucleolus 

paranucleus (paranu'kleus) n. [Gk. 
para, beside ; L. nucleus, a kernel.] 
A micronucleus ; a spherical mass 
of mitochondria (cyt.\ 

paraphysis (paraf'isis) n. [Gk. para, 
beside \physis, growth.] A slender 
filamentous epidermal outgrowth 
occurring among sporogenous 
organs (hot.) ; a non-nervous out- 
growth on the top of the brain of 
nearly all Vertebrates (zool.}. 

parapineal (paraplne'al) a. [Gk. 
para, beside ; L. pinea, a pine- 
cone.] Appl. an eye-like epiphysis 
of lampreys, the pineal body of 
other Vertebrates (zool.}. 

paraplasm (par'aplazm) n. [Gk. 
para, beside ; plasma, something 
moulded.] The vegetative or less 
active part of cell substance (cyt.). 

parapodium (parapo'dTum) n. [Gk. 
para, beside ; pous, a foot.] A 
paired process on the body- 
segments of Polychaets (zool.}. 




parapolar (parapo'lar) a. [Gk. para, 
beside ; polos, a pivot.] Beside the 
pole ; appl. the first two trunk cells 
in the development of Rhombozoa 

parapophysis (par'apof'isis) n. [Gk. 
para, beside ; apo, from ; physis, 
growth.] A transverse process 
arising from a vertebra centrum. 

parapteron (parap'teron) n. [Gk. 
para, beside ;pteron, a wing.] The 
tegula or shoulder-lappet or scapula 
of an insect mesothorax (zool.}. 

parapterum, parapteron. 

parapyles (par^apllz) n. plu. [Gk. 
para, beside ; pyle, a gate.] Two 
accessory openings in certain de- 
veloping Radiolarians (zool.). 

paraquadrate (parakwod'rat) n. [Gk. 
para, beside; L. quadratus, squared.] 
The squamosal, a hammer-shaped 
investing bone supporting the 
suspensorium, externally (zoo/.). 

pararectal (pararek'tal) a. [Gk. para, 
beside ; L. rectus, straight.] Be- 
side the rectum ; appl. fossa, lymph 
glands (anat.). 

parasite (par'aslt) n. [Gk. para, be- 
side ; sitos, food.] An organism 
living with or within another to its 
own advantage in food or shelter 

parasitic (parasit'lk) a. [Gk. para, 
beside ; sites, food.] Appl. an 
organism living at the expense of 
another, and in or on it (biol.). 

parasitic castration, castration 
caused by the presence of a para- 
site, as in certain male crabs in- 
fested by Sacculina (biol.). 

parasitism (par'asitizm) n. [Gk.para, 
beside ; sitos, food.] A form of 
symbiosis in which one symbiont, 
the parasite, receives advantage 
to the detriment of the other, the 
host (biol.). 

parasitology (par'asitol'oji) n. [Gk. 
para, beside ; sitos, food ; logos, 
discourse.] The science treating 
of parasites, especially those affect- 
ing human beings. 

parasphenoid (parasfe'noid) n. [Gk. 
para, beside ; sphen, wedge ; eides, 
like.] A membrane bone forming 
the floor of the cranium in certain 
Reptiles (zool.). 

parastemon (paraste'mSn) n. [Gk. 

para, beside ; stetnon, a warp.] A 
sterile stamen (dot.). 

parasternum (parasteYnum) n. [Gk. 
para, beside ; stcrnon, the breast.] 
The sum-total of the abdominal 
ribs of certain Reptiles (zool.). 

parastichy (paras'tikl) n. [Gk. para, 
beside ; stichos, row.] A secondary 
spiral in phyllotaxis (bot.). 

parately (parat'eli) n. [Gk. para, 
beside ; telos, end.] Evolution 
from unrelated material to that of 
type, but resulting in superficial 
resemblance (biol.). 

parathyroid (parathl'roid) a. [Gk. 
para, beside ; thyreos, a shield.] 
Beside the thyroid ; appl. small 
brownish-red glands (anat.). 

paratonic (paratSn'ik) a. [Gk. para, 
beside; tonos, pitch.] Stimulating; 
appl. the influence of light on grow- 
ing plants (bot.). 

paravesical (paraveVikal) a. [Gk. 
para, beside ; vesica, bladder.] 
Beside the bladder ; appl. a fossa 

paraxial (parak'sial) a. [Gk. para, 
beside ; L. axis, axle.] Alongside 
the axis ; appl. a medial column of 
mesoderm (emb.). 

parencephalon (par'SnkeTalon, -s6f-) 
n. \Gk.para, beside ; engkephalon, 
brain.] One of paired cerebral 

parenchyma (pareng'kima) n. [Gk. 
para, beside ; engchyma, infusion.] 
The soft, succulent tissue common- 
est in plants (bot.) ; the ground- 
work tissue of organs (zool.). 

parenchymalia (pargng'klma'llaj n. 
plu. [Gk. para, beside ; engchytna, 
infusion.] Spicules of the paren- 
chyma of Hexactinellids (zoo/.). 

parenchymatous (pargngkim'atus) a. 
[Gk. para, beside ; engchyma, in- 
fusion.] Pert, or found in paren- 
chyma ; appl. a kind of cell (bot.). 

parenchymula (pargngkim'ula) n. 
[Gk. para, beside ; engchyma, in- 
fusion.] A flagellate sponge larva 
with cavity filled with gelatinous 
connective tissue (zool.). 

parental generation, see F,, Pj. 

parhomology (par'hdmordji) n. [Gk. 
para, beside ; homos, alike ; logos, 
discourse.] Apparent similarity of 
structure (biol.). 



parles (pa'rlez) n. [L. paries, wall.] 
The central division of a compart- 
ment of Cirripedia (zool.~). 

parietal (parietal) a. [L. paries, wall] 
Pert, or forming part of the wall of 
an organ or structure ; appl. cells, 
membrane, lobe (zool^) ; layer (dot.}. 

parietal bone, a paired bone of the 
roof of the skull. 

parietomastoid (parl'etomas'toid) a. 
[L. paries, wall ; Gk. mastos, breast.] 
Connecting mastoid with parietal ; 
appl. a suture (anat.}. 

parieto-occipital (pari'eto-oksip'ital) a. 
[L. paries, wall ; occiput, back part 
of the head.] Appl. a fissure be- 
tween parietal and occipital lobes 
of the cerebrum (anaf.). 

parietotemporal (pari'etotem'poral) a. 
[L. paries, wall ; temporalis, tem- 
porary.] Pert, parietal and tem- 
poral regions ; appl. an artery 

paripinnate (par'ipin'at) a. [L. par, 
equal ; pinna, a wing.] Pinnate 
without a terminal leaflet (hot.}. 

paroccipital (paroksip'ital) a. [Gk. 
para, beside ; L. occiput^ back of 
the head.] Appl. .ventrally-deted 
processes of the exoccipitals 

paroecious (pare'shus) Si 
beside ; oikos, a house.] 
theridium and archegonium close.' 
to one another ; paroicous (bot.). 

parolfactory (par'olfak'tori) a. [Gk. 
para, beside ; L. olfactorius, ol- 
factory.] Appl. an area and sulcus 
adjoining the olfactory trigone of 
the rhinencephalon (anaf.). 

paronychia (par'omk'ia) n. plu. _[Gk. 
para, beside ; onyx, nail.] Bristles 
on the pulvillus of an insect foot 

paroophoron (par'ooforon) n. [Gk. 
para, beside ; oon, egg ; pherein, to 
bear.] A few scattered rudimentary 
tubules, remnants of the Wolffian 
body in the female (anaf.). 

parosteal (paros'teal) a. [Gk. para, 
beside ; osteon, bone.] Appl. ab- 
normal bone formations. 

parosteosis (par'osteo'sTs) n. [Gk. 
para, beside ; osteon, bone.] Bone 
formation in tracts normally purely 

parotic (parot'ik) n. [Gk. para, be- 
side ; ous, ear.] A process formed 

by 1 fusion of exoccipital and opis- 
thotic in adult lizards (zool.}. 

parotid glands, paired salivary 
glands opening into the mouth 
cavity of Mammals ; in some Am- 
phibians large swellings on the side 
of the head formed of aggregated 
cutaneousglands, sometimes poison- 
ous (zool.}. 

parovarium (par'ova'rium) n. [Gk. 
para, beside ; L. ovarium, ovary.] 
A small collection of tubules an- 
terior to the ovary, the remnant in 
the adult of the embryonic meso- 
nephros (zool.~). 

parthenogenesis (par'thenojSn'esis) n. 
[Gk. parthenos, virgin ; genesis, 
descent.] Reproduction without 
fertilization by a male element 

parthenogenetic (par'thenojenet'ik) a. 

Sjk. parthenos, virgin ; genesis, 
escent.] Appl. plants or animals 
developed from seed or ovum with- 
out fertilization by pollen or 
spermatozoon (biol.\ 

parthenogonidia (par'thenb'gonld'ia) 
n. plu. [Gk. parthenos, virgin ; 
gonos, offspring.] Zooids of a 
protozoan colony, with the function 
of asexual reproduction (sool.\ 

parthenospenn (par'thenosperm) n. 

j [Gk. parthenos, virgin ; sperma, 
seed.] A sperm produced without 
fertilization (hot.}. 

parthenospore (par'thenospor) n. 
[Gk. parthenos, virgin ; sporos, seed.] 
A spore produced without fertiliza- 
tion (bot.). 

partial involucre, see involucel. 

partial segmentation, see mero- 

partial umbel, see umbellule. 

partite (par'tlt) a. [L. partitus, 
divided.] Divided nearly to the 
base (bot.\ 

parumbilical (par'umbil'ikal) a. [Gk. 
para, beside ; umbilicus, the navel.] 
Beside the navel ; appl. small veins 
from the anterior abdominal wall 
to the portal and iliac veins (anat.). 

patagial (pata'jlal) a. [L. patagium, 
a border.] Pert, a patagium. 

patagiate (pata'jiat) a. [L. patagium, 
a border.] Furnished with a 

patagium (pata'jium) n. \L. patagium, 




a border.] The membranous ex- 
pansion between fore and hind 
limbs of bats and flying squirrels 
and foxes ; the similar expansion 
on a bird's wing ; a tegula, or 
dorsal process of the prothorax of 
certain Lepidoptera (zool.}. 

patella (pateTa) n. [L. patella, a 
small pan.] The knee-cap (zool.} ; 
a rounded apothecium of Lichens 

patellar (patel'ar) a. [L. patella, a 
small pan.] Pert, a patella. 

patelliform (patel'iform) a. {L.patella, 
a small pan ; forma, shape.] Shaped 
like a patella ; pan-shaped ; like a 
bordered disc. 

patent (pat'fint) a. [L. patens, lying 
open.] Spreading widely ; ex- 
panded (biol.}. 

pathetic (pathet'ik) a. [Gk. pathos, 
feeling.] Appl. the trochlear nerve 
and the superior oblique muscle of 
the eye (anat.}. 

pathogenic (path'ojSn'ik) a. [Gk. 
patJws, suffering ; genos, offspring.] 
Disease-producing ; appl. a parasite 
in relation to a particular host 

patina (pat'ma) n. [L. patina, a 
dish.] Circles of plates round 
calyx of Crinoids (zool:). 

patulent (pat'ulent),' patulous ( 
iilus) a. [L. patulus, sta 
open.] Spreading open ; expa 

paturon (patu'ron) n. [Gk. patein, 
to trample on.] The basal joint of 
arachnid chelicerae, used for crush- 
ing and expressing the -fluids of 
insects (zool.}. 

paulospore (pol'ospor) n. [Gk. paula, 
rest ; sporos, seed.] A resting or 
winter stage in development, as a 
cyst ; a stage of suspended de- 
velopment (biol.}. 

paunch (ponsh) n. [L. pantex, the 
paunch.] The rumen, an expansion 
of the oesophagus, the first stomach 
of ruminants (zool.}. 

pavement epithelium, simple 
squamous epithelium of flat, nucle- 
ated scales, fitting together like 
mosaic (phys.}. 

paxilla (paksll'a) n. [L. paxi/lits, a 
peg.] A thick plate supporting 
calcareous pillars, the summit of 

each covered by a group of small 
spines, a structure of certain 
Stelleroids (zool.}. 

paxillar (paksll'ar) a. [L. paxillus, 
a peg.] Pert, a paxilla. 

paxilliform (paksll'iform) a. [L. 
paxillus, a peg ; forma, shape.] 
Shaped like a paxilla. 

paxillus, a paxilla. 

pearl (pgrl) n. [F. perle, a pearl.] 
In the shells of some Mussels, an 
abnormal growth formed with a 
grain of foreign matter or a minute 
organism for nucleus and many thin 
layers of nacre surrounding it (zool.}. 

pectase (pek'las) n. \Gk.pektos, con- 
gealed.] An enzyme of plants 
which forms vegetable jelly. 

pecten (pgk'tgn) n. [L. pecten, a 
comb.] Any comb-like structure ; 
a process of the inner retinal 
surface in Reptiles, expanded into 
a folded quadrangular plate in 
Birds ; the stridulating organ of 
certain Arachnids (zool.}. 

pectic (pek'tik) a. [Gk. pektos, con- 
gealed.] Appl. acids and bodies 
consislw^ of pectase, pectin, 

a. [L. pecten, 
a pecten. 

(pgk'tinat) a. [L. pecten, 
.] Comb-like ; pectiniform ; 
appl. leaves (bot.}, a ligament of the 
iris (anat.}, certain gills, pedi- 
cellariae of Asteroids, a septum 
between the corpora cavernosa 

pectlneal (pgkttn'eal) a. [L. pecten, 
comb.] Afpl. a process of the 
pubis of Birds ; appl. a ridge-line 
on the femur and the muscle 
attached thereto (anat.}. 

pectinellae (pek'tlnele) n. plu. [L. 
pectinella, a small comb.] Trans- 
versely-planted, comb-like mem- 
branellae constituting the adoral 
ciliary spiral of some Infusoria 

pectinirhomb (pSk'tlnlromb') n. [L. 
pecten, comb ; Gk. rhombos, a magic 
wheel.] A type of stereom-folding 
in Cystidea (zool.}. 

pectoral (peYtoral) a. [L. pectus, 
breast.] Pert, the chest ; in the 
chest region ; appl. arch, girdle, 
fins, limbs (zool.}. 




pectoralis major and minor, outer 

and inner chest muscles connecting 

the ventral chest wall with shoulder 

and humerus (zool.). 
pectus (pSk'tiis) n. [L. pectus, breast.] 

The chest or breast region. 
pedal (ped'al) a. [L.#es, foot.] Pert. 

the foot or feet ; appl. cords, 

pedate (pgd'at) a. [L. pes, foot.] 

pedatipartite (pedat'ipar'tit) a. [L. 

pes, foot ; partitus, divided.] Appl. 

a variety of palmate leaf with 

cymose branching of the third order 

pedatisect (pedat'rsgkt) a. [L. pes, 
foot ; sectus, cut.] In pedate 
arrangement, and with divisions 
nearly to the midrib (bot.). 

pedicel (pgd'isel) n. [L. pediculus, a 
small foot.] A small, short foot- 
stalk of leaf, flower, fruit, or spor- 
angium (bot.) ; the foot-stalk or 
stem of a stationary and fixed or- 
ganism (zool.). 

pedicellariae (pgd'isglar'ie) n. plu. 
\L. pediculus, a small foot.] Minute 
pincer-like structures studding the 
surface of certain Echinoderms 

pedicellate (ped'isel'at) a. [L. pedicu- 
lus, a small foot.] Supported by a 
pedicel ; appl. Hymenoptera with 
stalked abdomen ; cf. pseudo-sessile 

pedicellus (ped'iseTus) n. [L. pedicu- 
lus, a small foot] A short foot- 
stalk (bot.) ; the second joint of 
insect antennae (zool.). 

pedicle (pgd'ikl) n. [L. pediculus, a 
small foot.] A short stem (bot.) ; 
a backward-projecting vertebral 
process (anat.) ; the narrow stalk 
uniting thorax with abdomen in 
Arachnids (zool.). 

pedipalpus (pgd'ipal'pus) n. [L. pes, 
foot ; palpare, to feel.] In Arach- 
nids, the second cephalothoracic 
paired appendage, variously a 
pincer-like claw, a simple or leg- 
like appendage, a chelate structure 

peduncle (pfidung'kl) n. [L. peduncu- 
lus, a small foot.] A stem or stalk, 
supporting flower or fruit (bot.) ; a 
band of white fibres joining differ- 

ent parts of the brain (anat.) ; the 
stalk of Brachiopods and Barnacles ; 
the link between thorax and ab- 
domen in Insects and Arachnids 

pedunculate (pediing'kulat) a. [L. 
pedunculus, a small foot.] Growing 
on or having a peduncle (biol.) ; 
appl. the primordial cerebral lobe 
of Hymenoptera (zool.). 

pelagic (pglaj'ik) a. [L. pelagus, the 
open sea.] Ocean-inhabiting. 

pelasgic (pelas'jlk) a. [L. Pelasgus, 
a Pelasgian.] Moving from place 
to place. 

pellicle (peTikl) n. [L. pellicula, a 
small skin.] The delicate pro- 
tective investment of Protozoa ; any 
filmy protective covering (biol.). 

pellions (pgl'ionz) n. plu. [Gk. pella, 
a cup.] Ring of plates supporting 
the suckers of Echinoids ; rosettes 

pelma (pel'ma) n. [Gk. pelma, sole.] 
The sole of the foot. 

peloria (pelo'ria) n. [Gk. pelorios, 
monstrous.] Condition of abnormal 
regularity ; a modification of struc- 
ture from irregularity to regularity 

peloric (pelor'ik) a. [Gk. pelorios, 
monstrous.] Appl. a flower which, 
normally irregular, becomes regular 

pelta (pel'ta) n. [Gk. pdte, a shield.] 
The shield-like apothecium of cer- 
tain Lichens (bot.). 

peltate (peTtat) a. [Gk. pelte, a 
shield.] Shield-shaped; fastened 
to the stalk at a point within the 
margin, as a leaf (bot.). 

pelvic (pgl'vik) a. [L. pelvis, a basin.] 
Pert, or situated at or near the 
pelvis ; appl. girdle, cavity, fin, 
limbs, plexus (zool.). 

pelvis (pel' vis) n. [L. pelvis, a basin.] 
In Vertebrates the bony cavity 
formed by the pelvic girdle along 
with the coccyx and sacrum ; the 
expansion of the ureter at its 
junction with the kidney (anat.) ; 
the basal portion of the cup of 
Crinoids (zool.). 

pen (pSn) n. [L. penna, a feather.] 
A leaf midrib (bot.) ; the skeletal 
part of a cuttlefish (zool.). 

pendulous (pgn'dulus) a. [L. pen- 




dere, to hang.] Bending down- 
wards from the point of origin ; 
overhanging ; appl. ovules, branches, 
flowers (bo /.). 

penial setae, paired needle-like 
chitinoid bodies at the anus of a 
round-worm, which also serves as 
reproductive aperture (zool.). 

penicillate (pgn'isll'at) a. [L. peni- 
cillum, a painter's brush.] Peni- 
cilliform ; pencil-shaped ; tipped 
with hairs ; having a structure like 
a camel-hair brush. 

penis (pe'nls) n. [L. penis, a penis.] 
The male copulatory organ. 

pennaceous (pfina'shus) a, [L.penna, 
feather.] Penniform ; like a plume 
or feather. 

pentacapsular (pgn'takap'sular) a. 
\Gk. Pente, five ; L. capsula, a cap- 
sule.] With five capsules (bot.). 

pentacarpellary (pgn'takarpeTari) a. 
[Gk. pente, five ; karpos, fruit.] 
With five carpels (bot.). 

pentachenium (pgn'take'nium) n, 
[Gk. pente, five ; a, not ; chainein, 
to gape.] A form of schizocarp 
with five carpels (bot.). 

pentacoccous (pSn'takok'us) a. [Gk. 
pente, five ; kokkos, kernel.] With 
five seeds or carpels (bot.). 

pentacrinoid (pgn'takrf noid) a. [Gk. 
pente, five ; krinon, a lily ; eidos, 
resemblance.] Resembling a Penta- 
crinus ; appl. a larval stage of 
Feather-stars, the fixed stalked 
stage like a Pentacrinus (zool.). 

pentactinal (pgntak'tTnal) a. [Gk. 
pente, five ; aktis, ray.] Five-rayed ; 

pentacyclic (pgn'tasik'llk) a. [Gk. 
pente, five ; kyklos, a circle.] Ar- 
ranged in five whorls (hot.}. 

pentadactyl (pen'tadak'til) a. [Gk. 
pente, five ; daktylos, a finger.] 
Having all four limbs normally 
terminating in five digits. 

pentadelphous (pgn'tadeTfus) a. [Gk. 
pente, five ; adelphos, brother.] 
Having five clusters of more or less 
united filaments (bot.). 

pentafld (pen'taffd) a. [Gk. pente, 
five ; ~L.findere, to cleave.] In five 
divisions or lobes (bot.). 

pentagonal (pe'ntag'onal) a. [Gk. 
pente, five ; gonia, angle.'] Appl. 
the symmetry of a pentamerous 

flower ; quinary ; having five angles 

pentagynous (pgntaj'inus) a. [Gk. 
pente, five ; gyne, a woman.] Having 
five styles (bot.). 

pentamerous (pentam'e'rus) a. [Gk. 
pente, five ; meros, part.] Com- 
posed of five parts ; in whorls of 
five or a multiple of five (bot.). 

pentandrous (pgntan'drus) a. [Gk. 
pente, five ; andros, male.] Having 
five stamens (&?/.) 

pentapetalous (pgn'tapeYalus) a. [Gk. 
Pente, five ; pefalon, a petal.] 
Having five petals (bot.). 

pentapterous (pfintap'tgrus) a. [Gk. 
pente, five ; pteron, wing.] With 
five wings, as some fruits (bot.\ 

pentasepalous (pgn'tasep'alus) a. 
[Gk. pente, five ; sepalon, sepal.] 
Having five sepals (bot.\ 

pentastichous (pgntas'tlkus) a. [Gk. 
pente, five ; stichos, a row.] Ar- 
ranged in five vertical rows (bot.~). 

pepo (pe'po) n. [Gk. pepon, melon.] 
An inferior one-celled, many- 
seeded pulpy fruit (bot.\ 

pepsin (pgp'sin) n. [Gk. pepsis, a 
digesting.] An enzyme secreted 
by the stomach (phys.}. 

peptic (pgp'tik) a. [Gk. pepsis, a 
digesting,] Relating to or pro- 
moting digestion ; appl. pepsin- 
secreting glands of the stomach 

peptonephridia (pgp'tongfrfd'ia) n.plu. 
[Gk. pepsis, digestion ; nephros* 
kidney.] The anterior nephridia 
of Oligochaets which function as 
digestive glands (zool.}. 

peraeopods, pereiopods. 

percurrent (pgrkur'gnt) a. [L. per- 
currens, running through.] Ex- 
tending throughout the entire 
length, or from base to apex (bot.}. 

pereion (pgrfon) n. [Gk. peraioun, to 
convey.] The thorax of Crustacea 

pereiopods (pgrfopSdz) n. plu. [Gk. 
peraioun, to convey ; ous, foot.] 
The locomotory thoracic limbs of 
Malacostraca ; trunk-legs (zool.). 

perennation (pgr'gna'shun) n. [L. 
per, through ; annus, a year.] 
Condition of living for a number 
of years (bof.). 

perennial (peYgnlal) a. [L per, 




through ; annus, year.] Persisting 
through the year or for a number 
of years (tot.). 

perennibranchiate (pgren'ibrang'kTat) 
a. [L. per, through ; annus, year ; 
Gk. brangchia, gills.] Having 
gills persisting throughout life, as 
certain Amphibians (zoo/.). 

perfoliate (pgrfo'Hat) a. [L. per, 
through ; folium, leaf.] Appl. a 
leaf with basal lobes so united as 
to appear as if the stem ran through 
it (tot.). 

perforate (per'forat) a. [L. perforare, 
to bore through.] Having holes 
or pores, as Corals, Foraminifers 
(zool.) ; appl. certain areas of the 
brain perforated by small blood- 
vessels (anat.). 

perforator (pgr'fora'tor) n. [L. per- 
forare, to bore through.] A barbed 
spear-like head and process of some 
spermatozoa, as of Salamander 

perhydridase (pgrhl'dridas) n. [L. 
per, through ; Gk. hydor, water.] 
An enzyme which causes the 
activation of perhydride hydrogen 

perianth (per'ianth) n. [Gk. peri, 
round ; anthos, flower.] A floral 
envelope ; the external floral whorls, 
including calyx and corolla (tof.). 

periblast (pgr'iblast) n. [Gk. peri, 
round ; blastos, a bud.] The outside 
layer, epiblast, or blastoderm of an 
insect embryo (emb.}. 

periblastic (pgriblas'tlk) a. [Gk.peri, 
round ; blastos, a bud.] Pert, the 
periblast ; superficial, as appl. 
segmentation (emb.}. 

periblastula (pgr'iblas'tula) n. [Gk. 
Peri, round ; blastos, bud.] A blastula 
resulting from periblastic segmenta- 
tion (emb.}. 

periblem (pgrTblgm) n. [Gk. peri, 
round ; blema, a coverlet.] Layers 
of ground or fundamental tissue 
between dermatogen and plerome 
of growing points (tot.). 

peribranchial (pgr'ibrang'klal) a. [Gk. 
peri, round ; brangchia, gills.] 
Around the gills ; appl. a type of 
gemmation and an atrial cavity in 
Ascidians ; appl. circular spaces 
surrounding basal parts of papulae 
of Asteroids (zoo/.). 

pericardiac (per'fkar'diak), peri- 
cardial (pgrTkar'dial) a. [Gk. peri, 
round ; kardia, heart.] Pert, the 
pericardium ; surrounding the 
heart ; appl. cavity, septum (anat.}. 

pericardium (pgrTkar'dium) n. [Gk. 
peri, round ; kardia, heart.] The 
cavity containing the heart ; the 
membrane enveloping the heart 

pericarp (pgr'ikarp) n. [Gk. peri, 
round ; karpos, fruit.] The ovary 
walls of fruits (tot.). 

pericentral (pgr'isen'tral) a. [Gk. 
peri, round ; L. centrum, centre.] 
Round or near the centre ; appl. 
auxiliary cells (tot.}. 

perichaetium (pgr'ike'shlum) n. [Gk. 
peri, round ; chaite, loose hair.] 
One of the membranes enveloping 
the archegonia of Mosses (tot.). 

perichondrium (pgr'ikon'drium) n. 

fGk. peri, round ; chondros, carti- 
age.J A fibrous membrane that 
covers cartilages (anat.}. 
perichordal (per'ikor'dal) a. [Gk. 
peri, round ; chorde, a cord.] 
Enveloping or near the notochord 

perichylous (pgr'iki'lus) a. [Gk. peri, 
round ; chylos, juice.] With water- 
storage cells outside the chlor- 
enchyma (tot.). 

pericladium (per'ikla'dium) n. [Gk. 
Peri, round ; klados, a branch.] 
The lowermost clasping portion of 
a sheathing petiole (tot.). 

periclinal (pgr'ikll'nal) a. [Gk. peri, 
round ; kleiein, to surround.] Appl. 
the system of cells parallel to the 
surface of the apex of a growing 
point (tot.}. 

periclinium (pgr'Iklin'ium) n. [Gk. 
Peri, round ; kline, a bed.] The 
involucre of a composite flower 

pericranium (pgr'ikra'nium) n. [Gk. 
peri, round ; kranion, skull.] The 
fibrous membrane investing the 
skull (anat.}. 

pericycle (pgr'isfkl) n. [Gk. peri, 
round ; kyklos, a circle.] The 
external layer of the stele (tot.). 

peridental (pgrTden'tal) a. [G\L.peri, 
round ; L. dens, tooth.] Investing 
a tooth ; appl. a membrane, or the 
periosteum of a root (anat.}. 




peridenn (pgr'idgrm) n. [Gk. peri, 
round ; derma, skin.] The outer 
layer of bark (dot.} ; the external 
cuticular layer of Hydrozoa (zool.}. 
peridesm (pgr'idgzm) n. [Gk. peri, 
round ; desme, a bundle.] Tissue 
surrounding a vascular bundle (bot.}. 
peridesmium (pgr'fdgz'mium) n. [Gk. 
peri, round ; desmos, a band.] 
Tissue surrounding a ligament 

peridlal (perld'ial) a. [Gk. peridion, 
a small wallet.] Pert, a peridium 

perididymis (pgr'idid'imTs) n. [Gk. 
pert, round ; didymos, a testicle.] 
The fibrous covering of the testis 

peridiolum (pgrid'iolum) n. [Gk. 
peridion, a small wallet.] A small 
peridium or collection of spores 
enclosed within the peridial covering 

peridium (pgrid'ium) n. [Gk. peridion, 
a small wallet.] The coat investing 
the sporophore of Fungi ; the outer 
covering of a puff-ball (dot.}. 
peridural (pgrtdu'ral) a. [Gk. peri, 
round ; L. durus, hard.] Appl. the 
perimeningeal space at a later stage 
of development (emb.}. 
perienteric (pgrtgn'tgrik) a. [Gk. 
peri, round ; enteron, the gut.] Sur- 
rounding the enteron (zool.}. 
perienteron (pgrtgn'tgron) n. [Gk. 
peri, round ; enteron, gut.] A 
cavity surrounding the enteron or 
visceral cavity (emb.}. 
perifbliary (pgrWliari) a. [Gk. peri, 
round ; L. folium, a leaf.] Round 
a leaf margin (bot.\ 
perigastric (pgr'igas'trlk) a. [Gk. 
peri, round ; gaster, stomach.] 
Surrounding the viscera ; appl. the 
abdominal cavity. 

perigastrula (per'igas'troola) n. [Gk. 
peri, round ; gaster, stomach.] 
The gastrula resulting after super- 
ficial segmentation (emb.}. 
perigonium (peVigo'nlum) n. [Gk. 
peri, round ; gone, generation.] A 
floral envelope or perianth ; the 
involucre round the antheridium of 
Mosses (bot.} ; a gonotheca (zool.}. 
perigynium (pSr'fjTn'Ium) n. [Gk. 
peri, round ; gyne, a female.] The 
fruit-investing utricle of the genus 

Carex ; the membranous perianth 
of Mosses (bot.}. 

perigynous (pgrlj'mus) a. [Gk. peri, 
round ; gyne, female.] Having 
sepals, petals, stamens round the 
gynoecium, not underneath ; cf. 
hypogynous (bot.}. 

perigyny (pgrij'inl) n. [Gk. peri, 
round ; gyne, a female.] Arrange- 
ment in a perigynous manner. 
perihaemal (peYlhe'mal) a. [Gk. 
peri, round ; haima, blood.] Appl. 
the blood-vascular system of canals 
and spaces of Echinoderms ; appl. 
dorsal outgrowths of the third body- 
cavity of Enteropneusta (zool.}. 
perilymph (peYllimf) n. [Gk. peri, 
round ; L. lympha, water.] A fluid 
separating the membranous from 
the osseous labyrinth of the ear 

perimedullary (peYime'duTari) a. 
[Gk. peri, round ; L. medulla, the 
marrow.] Surrounding the pith of 
a stem ; appl. a zone (bot.}. 
perimeningeal (pgr'imgnTn'jeal) a. 
[Gk. peri, round ; meningx, a mem- 
brane.] Appl. a space between the 
endorhachis and the meninx primi- 
tiva or spinal cord envelope (emb.}. 
perimysium (pgrTmiz'ium) n. [Gk. 
peri, round ; mys, a muscle.] Con- 
nective tissue binding numbers of 
fibres into bundles and muscles, 
and continuing into the tendons ; 
alternatively, appl. only to fasciculi 
envelopes ; cf. epimysium (anaf.}. 
perinaeal (pgr'Ine'al) a. [Gk. peri- 
naion, the part between anus and 
scrotum.] Pert, the perinaeum ; 
appl. artery, body, nerve (anat.}. 
perinaeum (pgr'Ine'um) n. [Gk. peri- 
naion, the part between anus and 
scrotum.] A surface of the body 
limited by the scrotum in front, the 
buttocks behind, and laterally by 
the medial side of the thigh (anaf.}. 
perinephrium (pgr'ingf'rlum) n. [Gk. 
peri, round ; nephros, kidney.] The 
enveloping tissue of the kidney 

perineurium (pgr'inu'rlum) n. [Gk. 
pert, round ; neuron, a nerve.] The 
tubular sheath of a small bundle of 
nerve fibres (anat.}. 
perinium (pgrln'fum) n. [Gk. peri, 
round ; is, a fibre.] An epispore, 




or microspore-coating of certain 
Pteridophytes (hot.). 

periodicity (pe'riodis'itT) n. [Gk.peri, 
round ; odos, a way.] The fulfil- 
ment of functions at regular periods 
or intervals ; rhythm (&/.). 

perioesophageal (per'ie'sofaje'al) a. 
[Gk.peri, round ; oisophagos, gullet.] 
Surrounding the oesophagus ; appl. 
a nerve ring (zoo/.). 

periosteum (peYlos'teum) n. [Gk. 
pert, round ; osteon, bone.] The 
connective membranous tissue in- 
vesting the surface of bones (anat.). 

periostracum (per'los'trakum) n. [Gk. 
peri, round ; ostrakon, shell.] The 
chitinous external layer of most 
Mollusc shells (zoo/.). 

periotic (peViot'ik) n. [Gk. peri, 
round ; ous, ear.] A cranial bone 
enclosing parts of the membranous 
labyrinth of the internal ear (anat.). 

peripetalous (per'ipet'alus) a. [Gk. 
peri, round ; petalon, a leaf.] Sur- 
rounding petals or a petaloid struc- 
ture (oof.). 

peripharyngeal (peYifarin'jeal) a. 
[Gk.peri, round ; pharyngx, gullet.] 
Encircling or surrounding the 
pharynx ; appl. the cilia of Ascidi- 
ans (zoo/.). 

peripheral (pgrlfgral) a. [Gk. peri, 
round ; pherein, to bear.] Distant 
from the centre ; near the circum- 
ference ; appl. end-organs of nerves, 
nervous system (anal.). 

peripherical (per'ifeYikal) a. [Gk. 
peri, round ; pherein, to bear.] 
Appl. an embryo more or less 
completely surrounding the endo- 
sperm in the seed (dot.). 

periphery (pe'rif'e'ri) n. [Gk. peri, 
round ; pherein, to bear.] The 
boundary outline of a surface or 

periphysis (pgrlf'isis) n. [Gk. peri, 
round ; physis, growth.] In certain 
Fungi, a filament branching from 
a hymenium without asci (bot.). 

periplasin (per'iplazm) n. [Gk. peri, 
round ;^/^wa,somethingmoulded.] 
The region of an oogonium outside 
the oosphere, in Fungi (bot.). 

periplast (peYiplast) n. [Gk. peri, 
round ; plastos, moulded.] The 
attraction-sphere (cyt.) ; the ecto- 
plasm of flagellates ; the firm cuticle 

of certain . Mastigophora ; inter- 
cellular substance of tissues (zoo/.). 

peripneustic (peVipnu'stik) a. [Gk. 
peri, round ;pneustikos,pert. breath- 
ing.] Having stigmata arranged 
along the sides of the body, normal 
in insect larvae (zoo/.). 

periproct (per'iprokt) n. [Gk. peri, 
round ; proktos, anus.] The surface 
immediately surrounding the anus 
of Echinoids (zoo/.). 

perisarc (peYlsark) n. [Gk. peri, 
round ; sarx, flesh.] The tough 
outer membrane of Hydrozoa (zoo/.). 

periscleral (peYiskle'ral) a. [Gk. 
peri, round ; skleros, hard.] Appl. 
a lymph-space external to the sclera 
of the eye (anat.). 

perisome (peYisom) n. [Gk. peri, 
round ; soma, body.] A body-wall ; 
the integument of Echinoderms 

perisperm (peYisperm) n. [Gk. peri, 
round ; sperma, seed.] The re- 
mains of the nucellus of an ovule 
when it is not all absorbed during 
development of the embryo (bot.). 

perispore (per'ispor) n. [Gk. peri, 
round; sporos, seed.] A spore- 
covering ; the mother cell in Algae 
spores (bot.). 

peristalsis (per'istal'sis) n. [Gk. peri, 
round ; s tell fin, to place.] Move- 
ment of the digestive tract, by which 
food is digested and absorbed, by 
means of involuntary muscles 

peristaltic (pgr'istal'tlk) a. [Gk. peri, 
round ; stellein, to place.] Af. 
the movement by which fo 
digested, forced along the aliment- 
ary canal (pkys.). 

peristethium (peYiste'thmm) n. [Gk. 
peri, round ; stethos, breast.] An 
insect mesosternum. 

peristome (peVistom) n. [Gk. peri, 
round; stoma, mouth.] The region 
surrounding the mouth ; used in 
connection with Mosses (bot.), Vorti- 
cella, Actinozoa, Annulates, Insects 

perisystole (peVfsis'tole) n. [Gk. peri, 
round ; systole, a drawing together.] 
The interval elapsing between 
diastole and systole of the heart 

perithecium (per'ithe'shium) n. [Gk. 




peri, round ; theke, a case.] A 
flask-shaped cavity with terminal 
ostiole in stroma of Fungi (hot.}. 

peritoneal (peVitone'al) a. [Gk. peri, 
round ; teinein, to stretch.] Pert. 
the peritoneum ; appl. cavity, fossa, 
membrane (anat.). 

peritoneum (peYitone'um) n. [Gk. 
peri, round ; teinein, to stretch.] 
A serous membrane partly applied 
against the abdominal walls, partly 
reflected over the contained viscera 

peritreme (per'itrem) n. [Gk. peri, 
round ; trema, a hole.] The margin 
of a shell-opening ; the small plate 
perforated by the spiracle-opening 
in Insects (zoo/.). 

peritrichous (peVitrik'us) a. [Gk. 
peri, round ; thrix, hair.] Having 
the adoral band of cilia arranged 
in a spiral as in Vorticella (zoo/.). 

peritrochium (peYitro'klum) n. [Gk. 
peri, round ; trochos, a wheel.] A 
ciliary band ; a circularly ciliated 
larva (zoo/.). 

peritrophic (per'itrof'ik) a. [Gk.peri, 
round ; trophe, food.] Appl. a fold 
of membrane in the latter part of 
the intestine of Insects (zoo/.). 

perivascular (peVivas'kular) a. [Gk. 
peri, round ; L. vasculum, a small 
vessel.] Surrounding the blood- 
vessels ; appl. lymph channels 

perivisceral (peVivIs'gral) a. [Gk. 
peri, round ; L. viscera, bowels.] 
Surrounding the viscera ; appl. the 
body cavity. 

perivitelline (pgr'Tvitglfn) a. [Gk. 
peri, round ; L. vitellus, yolk of 
egg.] Surrounding the yolk of an 

permanent cartilage, cartilage 
which remains unossified through- 
out life ; opp. temporary (zoo/.). 

permanent teeth, the set of teeth 
developed after the milk or decidu- 
ous dentition ; the second set of 
most, the third set of some, the first 
set of other Mammals. 

permanent tissue, tissue consisting 
of cells which have completed their 
period of growth and subsequently 
change little till they lose their 
protoplasm and die (bot.}. 

Permian (peYmtan) a. [Perm, E. 

Russia.] The sixth rock-system of 
the primary group (pall). 

peronate (peVonat) a. [L. peronatus, 
rough - booted.] Covered with 
woolly hairs ; powdery or mealy 
externally (btol.}. 

peroneal (pgrone'al) a. [Gk. perone, 
the fibula.] Pert, or lying near the 
fibula ; appl. artery, nerve (anat.}. 

peroneotibial (peYone'otlb'Ial) a. [Gk. 
perone, fibula ; L. tibia, the tibia.] 
In the region of fibula and tibia ; 
appl. certain muscles (anat.}. 

peronium (pSro'mum) n. \Gk.perone, 
a fibula.] In Trachomedusae, one 
of the mantle-rivets, or cartilaginous 
processes ascending from the disc 
margin towards the centre (zoo/.). 

peroral (pSro'ral) a. [L.fler, through ; 
os, mouth.] Appl. a membrane of 
Infusoria formed by concrescence 
of rows of cilia (zoo/.). 

peroxidase (pgrflk'sidas) n. [L. per, 
through ; Gk. oxys, sharp.] An 
enzyme which causes the activation 
of peroxide oxygen (phys.}. 

perradius (peYra'dtus) n. [L. per, 
through ; radius, a radius.] One of 
four primary radii of Coelenterates 

persistent (pSrsIs'tSnt) a. [L. per, 
through ; sistere, to be fixed.] Re- 
maining attached till maturation, 
as a corolla (dot.} ; appl. organs or 
parts in the adult which normally 
disappear with larval stage or 
youth, as gills (zoo/.). 

person (peVs5n) n. [L. persona, a 
person.] An individual or zooid of 
a colony (zoo/.). 

personate (peYsonat) a. [L. person- 
atus, masked.] Appl. a corolla of 
two lips, closely approximated and 
with a projection of the lower closing 
the throat of the corolla (dot.}. 

perspiration (peYspfra'shun) n. [L. 
per, through ; spirare, to breathe.] 
Exudation or excretion through the 
pores of the skin (phys.}. 

pertusate (pgrtu'sat) a. [L. pertusus, 
thrust through.] Pierced at the 
apex (oof.). 

perula (peVula, pgr'oola) n. [Gk. 
Pera, a wallet.] A leaf-bud scale 

pervalvar (pgrval'var) a. [L. per, 
through ; valvae, folding-doors.] 




Dividing a valve longitudinally 

pervious (per'vius) a. [L.per, through ; 
via, a way.] Perforated ; permeable 
(btol.} ; appl. nostrils with no septum 
between the nasal cavities (zool.}. 
pes (pez) n. [L. pes, foot.] A foot or 
foot-like structure ; as certain parts 
of the brain, branches of the facial 
nerve (anat.}. 

pessulus (peVulus) n. [L. pessulus, a 
bolt.] An internal skeletal element 
in the syrinx of some Birds, 
petal (pet'al) n. \Gk.petalon, a petal.] 
One of the separate parts of a 
corolla (bot.}. 

petaliform (pgtal'iform) a. [Gk. 
petalon, petal ; L. forma, shape.] 
Petal-shaped ; petal-like ; petaloid ; 

petalled (peVald) a. [Gk. petalon, a 
petal.] With petals ; petaliferous ; 
opp. apetalous (bot.}. 
petalody (pgtal'ddi) n. [Gk. petalon, 
petal : eidos, resemblance.] Con- 
version of other parts of a flower 
into petals (hot.). 

petaloid (p&'aloid) a. [Gk. petalon, 
petal ; eidos, resemblance.] Like a 
petal (biol.} ; appl. the ambulacral 
areas of certain Echinoderms (zool.}. 
petaloideous (pet'aloid'eus) a. [Gk. 
petalon, petal ; eidos, resemblance.] 
Petaloid ; appl. monocotyledons 
with coloured perianth (bot}. 
petasma (ptaz'ma) n. \Gk.petasma, 
anything spread out.] A compli- 
cated membranous plate on the 
inner side of the peduncle with 
interlocking coupling hooks, an 
apparatus of certain Crustacea 

petiolar (pgt'iolar) a. [L. petiolus, 
a little foot.] Pert, having, or 
growing on a small stalk (bot.}. 
petiolate (pgt'iolat) a. [L. petiolus, 
a small foot.] Growing on a petiole 
(bot.} ; having thorax and abdomen 
connected by a petiole (zool.}. 
petiole (pet'iol) n. [L. petiolus, a 
small foot.] The foot-stalk of a 
leaf (bot.} ; a slender stalk connect- 
ing thorax and abdomen in Insects 

petiolule (pgt'io'lul) n. [L. petiolus, 
a small foot.] The foot-stalk of a 
leaflet of a compound leaf (bot.}. 

petrohyoid (pet'rohi'oid) a. [Gk. 
petros, stone ; hyoeides, Y-shaped.] 
Pert, hyoid and petrous part of 
temporal (anat.}. 

petromastoid (pet'romas'toid) a. [Gk. 
petros, stone ; mastos, breast.] Pert. 
the mastoid process and the petrous 
portion of the temporal (anat.}. 
petrooccipital (pet'rooksip'ital) a. 
[Gk. petros, stone ; L. occipzit, back 
of the head.] Pert, occipital and 
petrous part of temporal ; appl. a 
fissure (anat.}. 

petrosal (pgtro'sal) a. [Gk. petros, 
stone.] Solidly bony ; appl. a 
sphenoidal process, a ganglion of 
the glossopharyngeal, to nerves and 
sinus in the region of the petrous 
portion of the temporal bone (anat.}; 
appl. the otic bones of Fishes (zool. }. 
petrosphenoidal (pet'rosfenoid'al) a. 
[Gk. petros, stone ; sphen, wedge.] 
Pert, sphenoid and petrous part of 
temporal ; appl. a fissure (anat.}. 
petrosquamosal (pet'roskwamo'sal) a. 
[Gk. petros, stone ; L. squama, 
scale.] Pert, squamosal and petrous 
part of temporal ; appl. sinus and 
suture (anat.}. 

petrotympanic (pSt'rotimpan'ik) a. 
\G\a.petros, stone ; tympanon, drum.] 
Pert, tympanum and petrous por- 
tion of temporal ; appl. a fissure 

petrous (pet'riis) a. [Gk. petros, 
stone.] Very hard or stony ; appl. 
a pyramidal portion of the tem- 
poral .bone wedged in between 
sphenoid and occipital ; also a 
ganglion on its lower border 

Peyer's patches, oval patches of 
aggregated lymph follicles on the 
intestine walls (zool.}. 
phacella (fasgl'a) n. [Gk. phakelos, 
a bundle of faggots.] A delicate 
filament with mesogloea core, and 
supplied with stinging capsules, 
occurring in rows in the stomach 
of certain Coelenterates (zool.}. 
phacoid (fak'oid) a. [Gk. phako, a 
lentil ; eidos, resemblance.] Lentil- 

phaeism (fe'izm) n. [Gk. phaios, 
dusky.] Duskiness ; appl. the 
colouring of butterflies, 
phaeochrome (fe'okrom) n. [Gk. 




phaios, dusky ; chroma, colour.] 

phaeochrous (feSk'rus) a. [Gk.phaios, 
dusky ; chros, colour.] Of dusky 

phaeodium (feo'dlum) n. \Gk..phaios, 
dusky ; eidos, resemblance.] In 
certain Protozoa, an aggregation 
of food and excretory substances 
forming a mass round the central 
capsule aperture (zool.). 

phaeophyll (fe'of il') n. [Gk. phaios, 
dusky; phyllon, a leaf.] The 
colouring matter of brown Algae 

phagocyte (fag'oslt) n. [Gk. phagein, 
to eat ; kytos, hollow.] A colour- 
less blood-corpuscle which tends 
to take in and destroy foreign 
particles (phys.). 

phagocytosis (fag'oslto'sis) n. [Gk. 
phagein, to eat ; kytos, hollow.] 
The ingestion and destruction of 
microparasites by phagocytes 

phagolysis(fagorisTs) n. [Gk. phagein, 
to eat ; lysis, a loosing.] Dissolu- 
tion of phagocytes (phys.}. 

phalange (') n. [Gk. phalangx, 
line of battle.] A bundle of stamens 
united by filaments (dot.). 

phalangeal (falan'jeal) a. [Gk. 
phalangx, line of battle.] Pert, the 
phalanges ; appl. bones, processes 
of Corti's rods, etc. (anat.). 

phalanx (fal'angks) //., phalanges 
(falan'jez) plu. [Gk. phalangx, line 
of battle.] Segments of the digits 
of Vertebrates. 

phallus (fal'us) n. [Gk. phallos, 
penis.] A penis. 

phanerocodonic (fan'erokodon'ik) a. 
[Gk. phaneros, manifest ; kodon, a 
bell.] Appl. detached and free- 
swimming zooids of a hydroid 
colony (zool.). 

phanerogam (fangr'ogam) n. [Gk. 
phaneros, manifest ; games, union.] 
A phaenogam or plant with con- 
spicuous flowers ; cf. cryptogam 

phanerogamous (fanSrog'amus) a. 
[Gk. phaneros, manifest : gamos, 
union.] Appl. plants with flowers 
containing pistils and stamens 

pharyngeal (farin'jeal, far'inje'al) a. 

[Gk. pharyngx, gullet or windpipe.] 
Pert, the pharynx ; ap>pl. artery, 
membrane, nerve, tonsil, tubercle, 
veins (anat.). 

pharyngobranchial (farlng'gobrang'- 
klal) a. [Gk. pharyngx, gullet ; 
brangchia, gills.] Pert, pharynx 
and gills ; appl. certain bones of 
Fishes (zool.). 

pharyngopalatine (farlng'gopal'atin) 
a. [Gk. pharyngx, gullet ; L. pal- 
atus, palate.] Pert, pharynx and 
palatine ; appl. arch and muscle 

pharynx (faYingks) n. {Gk. pharyngx, 
gullet or windpipe.] A musculo- 
membranous tube extending from 
the under surface of the skull to 
the level of the sixth cervical ver- 
tebra (anat.) ; the gullet or anterior 
part of the alimentary canal follow- 
ing the buccal cavity (zool.). 

phelloderm (feToderm) n. [Gk. 
phellos, cork ; derma, skin.] The 
secondary parenchymatous suber- 
eous cortex of trees, formed on the 
inner side of the cork-cambium 

phellogen (fel'ojen) n. [Gk. phellos, 
cork ; gene, production.] The cork 
cambium of tree stems, arising as a 
secondary meristem (dot.). 

philtrum (fil'trum) n. [Gk. philiron, 
a philtre.] The depression on the 
upper lip beneath the septum of the 
nose (anat.). 

phlebenterlsm (fleb6n'tgrtzm) n. [Gk. 
phleps, vein ; enteron, intestine.] 
Condition of having branches of 
the intestine extending into other 
organs, as arms or legs (zool.). 

phleboedesis (flebe'desls) n. [Gk. 
phleps, vein ; oidein, to swell.] 
Condition of having the circulatory 
system cavity so distended and 
insinuated as to diminish the 
coelom, especially so in Molluscs 

phloem (flo'Srn) n. [Gk. phloios, 
smooth bark.] The soft bast of 
vascular bundles, consisting of 
sieve-tube tissue (dot.). 

phloem parenchyma, thin -walled 
parenchyma associated with the 
sieve-tubes of phloem (dot.). 

phloem sheath, the pericycle, to- 
gether with the inner layer of a 



bundle sheath where the latter 
consists of two layers (bot.}. 

phloeoterma (fle'oteYma) n. [Gk. 
phloios, bark ; terma, end.] Endo- 
dermis ; innermost layer of cortex 

pholidosis (fol'ido'sis) n. [Gk. pholis, 
scale.] Scale arrangement of scaled 

phonation (fb'na'shun) n. [Gk. phone, 
sound.] Of Insects, sound pro- 

phoranthium (foran'thium) n. [Gk. 
pherein, to bear ; anthos, flower.] 
The receptacle of composite plants 

phorozooid (fo'rozo'oid) n. [Gk. 
pherein, to bear ; zoon, animal ; 
eidos, resemblance.] Foster forms 
of Doliolum buds, never sexually 
mature but set free with gonozooids 
attached to a ventral outgrowth 

phosphene (fos'fen) n. [Gk. phos, 
light ; phainein, to show.] A light 
impression on the retina due to 
stimulus other than rays of light 

phosphorescence (fos'fores'ens) n. 
[Gk. phosphoros, bringing light.] 
The state of being luminous without 
sensible heat ; common in marine 
Protozoa, some Copepods, and the 
majority of deep-sea animals. 

photodynamics (fo'todinam'iks) n. 
[Gk. phos, light ; dynamis, strength.] 
The study of the effects of light- 
stimulation on plants (hot.}. 

photogen (fo'tojen) n. [Gk. phos, 
light ; gene, production.] The light- 
producing organ of certain Poly- 
chaets (zool}. 

photogenic (fo'tojgn'ik) a. [Gk. phos, 
light ; gene, production.] Light- 
producing ; phosphorescent. 

photopathy (fotop'athi) . [Gk. 
phos, light ; pathos, feeling.] Re- 
sponse 16 light stimulus (bot.}. 

photophilous (fotof'ilus) a. [Gk. 
phos, light ;philos, loving.] Seeking 
and thriving in strong light (hot.}. 

photophore (fo'tofor) n. [Gk. phos, 
light ; pherein, to bear.] A phos- 
phorescent organ of Fishes (zool.}. 

photophygous (fotofigus) a. [Gk. 
phos, light ; phyge, flight] Avoiding 
strong light (biol}. 

photospheres (fo'tosf erz) n. plu. [Gk. 
phos, light ; sphaira, a globe.] 
Luminous organs of certain Crus- 
tacea (zool.}. 

photosynthesis (fo'tosin'thests) n. 
[Gk. phos, light ; synthesis, a putting 
together.] Carbon assimilation 

phototaxis (f 6'totak'sis) n. [Gk. 
phos, light ; taxis, an arrangement.] 
Response to the stimulus of light 

phototonus (fo'toto'nus) n. \Gk.phos, 
light ; tonos, a stretching/] Sensi- 
tiveness to light ; the condition of 
a plant or plant organ induced by 
light (bot.}. 

phototropism (fdtot'ropizm) n. [Gk. 
phos, light ; trope, a turning.] The 
tendency shown by most plants to 
turn their growing parts towards 
the greater light (bot.}. 

pliragma (frag'ma) n. [Gk. phragina, 
a fence.] A spurious dissepiment ; 
a septum (bot.} ; a thoracic partition 
in Insects (zool}. 

phragmocone (frag'mokon) n. [Gk. 
phragma, fence ; konos, a cone.] 
In Belemnites and other Molluscs, 
a cone divided internally by a series 
of septa perforated by a siphuncle 

phrenic (fren'ik) a. [Gk. phren, 
diaphragm.] Pert, or in the region 
of the diaphragm ; appl. artery, 
nerve, plexus, vein (anal}. 

phrenicocolic (fren'lkokol'ik) a. [Gk. 
phren, diaphragm ; kolon, part of 
intestine.] Appl. a ligament, con- 
sisting of a fold of peritoneum from 
left colic flexure to diaphragm (anat.}, 

phrenicocostal (fren'lkokos'tal) a, 
[Gk. phren, diaphragm ; L. costa, 
rib.] Appl. a narrow slit or sinus 
between the costal and diaphrag- 
matic pleurae (anat.}. 

phrenicolienal (frgn'iktille'nal) a. [Gk. 
phren, diaphragm ; L. lien, spleen.] 
Appl. a ligament forming part of 
the peritoneum reflected over the 
spleen and extending to the dia- 
phragm (anat}. 

diak) a. [Gk. phren, diaphragm ; 
peri, round ; kardia, heart.] Appl. 
a ligament extending from dia- 
phragm to pericardium (anat.}. 




phycochrome (fl'kokrom) n. [Gk. 
phykos, seaweed ; chroma, colour.] 
The colouring matter of blue-green 
Algae (dot.). 

phycocyanln (ffkosi'anin) n. [Gk. 
phykos, seaweed ; kyanos, dark blue.] 
The pigment of blue-green Algae 

phycoerythrin (f I'koeVithrin) n. [Gk. 
phykos, seaweed ; erythros, red.] 
The colouring matter of red Algae 

phycology (fikol'qjT) n. [Gk. phykos, 
seaweed ; logos, discourse.] The 
part of Botany dealing with Algae. 

phycophaein (fi'kofe'm) n. [Gk. 
phykos, seaweed ; phaios, dusky.] 
The pigment of brown Algae (hot.}. 

phycoxanthin (fl'kozan'thin) n. [Gk. 
phykos, seaweed ; xanthos, yellow.] 
The buff-coloured substance of 
diatoms (bot.). 

phylactocarp (filak'tokarp) n. [Gk. 
phylaktikos, guard ing; karpos, fruit.] 
A modification of the hydrocladium 
in Hydromedusae for the protec- 
tion of the gonophore (zool.). 

phylepheblc (fi'lefe'bik) a. [Gk. 
phylon, a race ; ephebeia, manhood.] 
Appl. the adult stage in race 
history (biol.). 

phyletic (fllet'ik) a. [Gk. phylon, 
race.] Pert, a phylum or race 

phyllade (fil'ad) n. [Gk. phyllas, 
foliage.] A reduced scale-like leaf 

phyllary (fil'ari) n. [Gk. phyllon, 
leaf.] One of the bracts of the in- 
volucres of Compositae (dot.). 

phyllidia (filid'ia) n. plu. [Gk. 
phyllidion, a little leaf.] Four out- 
growths from the side of the scolex 
ofCestoidea; bothridia (zool.). 

phyllobranchia (fil'obrang'kia) n. 
[Gk. phyllon, .leaf ; brangchia, gills.] 
A gill consisting of numbers of 
lamellae or thin plates (zool.). 

phyllocladium (fil'okla'dlum) n. [Gk. 
phyllon, leaf; klados, sprout.] A 
green flattened or rounded stem 
functioning as a leaf, as in Cactus 

phyllocyst (f il'osTst) n. [Gk. phyllon, 
leaf; kystis, bladder.] The rudi- 
mentary cavity of a hydrophyllium 
or protective medusoid (zool.). 

phyllode (ffl'od) n. [Gk. phyllon, 
leaf ; eidos, resemblance.] A winged 
petiole with flattened surfaces placed 
laterally to the stem, functioning as 
a leaf (bot.). 

phyllody (fil'odi) n. [Gk. phyllon, 
leaf; eidos, resemblance.] The 
metamorphosis of an organ into a 
foliage leaf (bot.). 

phyllogenetlc (ffl'qjeneYik) a. [Gk. 
phyllon, leaf; genesis, descent.] 
Producing or developing leaves 

phylloid (fil'oid) a. [Gk. phyllon, 
leaf; eidos, resemblance.] Leaf-like. 

phyllomania (fiToma'nia) n. [Gk. 
phyllon, leaf; mania, madness.] 
Abnormal leaf-production (bot.). 

phyllomorphosis (fTl'omor'fosis) n. 
[Gk. phyllon, leaf; morphe, form.] 
Phyllody ; variation of leaves at 
different seasons (bot.). 

phyllophagous (filof'agus) a. [Gk. 
phyllon, leaf; phagein, to eat.] 
Feeding on leaves (zool.}. 

phyllophore (fil'ofor) n. [Gk. phyllon, 
leaf; pherein, to bear.] The ter- 
minal bud or growing point of 

phyllophorous (filof'orus) a. [Gk. 
phyllon, leaf; pherein, to bear.] 
Bearing or producing leaves (bot.). 

phyllopode (fil'opod) n. [Gk. phyllon, 
leaf ; pous, foot.] A sheathing leaf 
of Isoetes (bot.). 

phyllopodium (fll'opo'dium) n. [Gk. 
phyllon, leaf; pous, foot.] The 
axis of a leaf (bot.). 

phyllopodous (filop'odus) a [Gk. 
phyllon, leaf; pous, foot.] Having 
leaf-like swimming-feet, as in Bran- 
chiopods and Cladocera (zool.). 

phylloptosis (fllopto'sis) n. [Gk. 
phyllon, leaf; ptosis, a falling.] 
The fall of the leaf (bot.). 

phyllospondylous (fil'ospon'dilus) a. 
[Gk. phyllon, leaf; sphondylos, 
vertebra.] Appl. vertebrae con- 
sisting of hypocentrum and neural 
arch, both contributing to the 
hollow transverse process, as in 
Stegocephals (zool.). 

phyllotaxis (fil'otak'sTs) n. [Gk. 
phyllon, leaf; taxis, arrangement.] 
The system of leaf-arrangement on 
an axis or stem (bot.). 

phylloxanthin, see xauthophyll. 




phyllozooid (fll'ozo'oid) n. [Gk. 
phyllon, leaf; zoon, animal.] A 
shield-shaped medusoid of pro- 
tective function ; a hydrophyllium 
of Hydromedusae (zool.). 

phylogenesis, phylogeny. 
phylogenetic (fl'lqjengt'ik) a. [Gk. 
phylon, race ; genesis, descent.] 
Pert, race - history ; appl. repro- 
ductive cells as opp. autogenetic or 
body cells (biol.). 

phylogeny (flloj'eni) n. [Gk. phylon, 
race ; genesis, descent.] The 
history of the development of a 
species or race, as opp. ontogeny, 
that of the individual {biol.}. 

phylogerontic (fl'lqjgron'tlk) a. [Gk. 
phylon, race ; geron, an old man.] 
Appl. the decadent stage in race- 
history (biol.). 

phylon (fi'lon), phylum (fl'lum) n. 
phyla (fTla) plu. [Gk. phylon, a 
race or tribe.] A group of animals 
or plants constructed on a similar 
general plan ; a division in classifi- 
cation (biol.). 

phyloneanic (fi'lonean'ik) a. [Gk. 
phylon, race ; neanikos, youthful.] 
Appl. the youthful stage in race- 
history (biol.'). 

phylonepionic (fl'longp'ionlk) a. [Gk. 
phylon, race ; nepios, infant.] Appl. 
the post-embryonic stage in race- 
history (biol.). 

physicist (fiz'isist) n. [Gk. physikos, 
physical.] An upholder of the 
theory that vital phenomena are 
explicable on a physico-chemical 
basis (biol.). 

physiogeny (fiziqj'e'ni) n. [Gk. physis, 
nature ; gene, production.] The 
development of vital activities 

physiological zero, see zero. 

physiology (ffz'iol'oji) n. [Gk. physis, 
nature ; logos, discourse.] The 
study of functions and activities of 

physoclistous (fi'soklls'tus) a. [Gk. 
physa, bladder ; kleiein, to close.] 
Having no channel connecting 
swim-bladder and digestive tract, 
as in most Teleosts (zool.). 

physodes (fl'sodz) n. plu. [Gk. physa, 
a bubble.] Spindles of phoro- 
glucin contained in the plasmodium 
of certain Sarcodina (zool.). 

physostomous (fisos'tomus) a. [Gk. 
physa, a bladder ; stoma, mouth.] 
Having swim-bladder and digestive 
tract connected throughout life by 
the pneumatic duct, as in Ganoids 

phytobiology (fl'tobloTqji) n. [Gk. 
phyton, plant ; bios, life ; logos, dis- 
course.] The life-history of plants. 

phytochemistry (fftokem'istri) n. 
[Gk. phyton, plant ; chymeia, an 
infusion.] The chemistry of plant 

phylogenesis (fi'tojen'e'sis) n. [Gk. 
phyton, plant ; genesis, descent.] 
The development of plants. 

phytogeography (fi'tojeog'rafi) n. 
[Gk. phyton, plant ; ge, earth ; 
graphein, to write.] Geographical 
distribution of plants. 

phytoid (fi'toid) a. [Gk. phyton, 
plant ; eidos, resemblance.] Plant- 

phytology (fltol'djl) n. [Gk. phyton, 
plant ; logos, discourse.] Botany. 

phytoma (flto'ma) n. [Gk. phyton, 
plant.] Vegetative plant-substance 

phytomer (fl'tomer) n. [Gk. phyton, 
plant ; meros, part.] A structural 
unit of a plant ; a bud-bearing node 

phytomorphic (fl'tomor'fik) a. [Gk. 
phyton, plant ; morphe, form.] With 
plant-like structure. 

phyton (fl'ton) n. [Gk. phyton, plant.] 
A rudimentary plant ; a phytomer 

phytonomy (fiton'oml) n. \Gk.phyton, 
plant ; nomos, law.] The laws of 
origin and development of plants. 

phytophagous (fitof'agus) a. [Gk. 
phyton, plant ; phagein, to eat.] 
Feeding on plants ; herbivorous 

phytophilous (fltofilus) a. [Gk. 
phyton, plant ; philos, loving.] 
Plant-eating (zool.). 

phytophysiology (fl'tofiz'iol'qji) n. 
[Gk. phyton, plant ; physis, nature ; 
logos, discourse.] Plant physiology, 
a branch of Botany, 
phytoplasm (fl'toplazm) n. [Gk. 
phyton, plant ; plasma, something 

moulded.] The protoplasm of 

plants (bot.). 
pia mater (pe'a mat'eY, pl'a ina'ter) n. 




[L. pia mater, kind mother.] A 
delicate highly vascular membrane 
investing brain and spinal cord 

pigment (pig'me'nt) n. [L. pingere, 
to paint.] Colouring matter in 
plants or animals. 

pigment cell, a chromatophore or 
cell containing colouring matter 

pigmentation (plg'me'nta'shun) n. [L. 
pingere, to paint.] Disposition of 
colouring matter in an organ or 
organism (dio!.). 

pileate i (pll'ea'te'd) a. [L. pileus, a felt 
cap.] Crested ; appl. Birds (zoo!.). 

pileolated (pil'eola'tgd) a. [L. pileolus, 
a small cap.] Furnished with a 
small cap or caps. 

pileolus (plle'olus) n. [L. pileolus, a 
small cap.] A small pileus. 

pileorhiza (pll'eori'za) n. [L. pileus, 
a cap ; Gk. rhiza, root.] A root- 
covering ; a root-cap (dot.). 

pileum (pil'eum) n. [L. pileum, a 
cap.] The top of the head region 
of a bird. 

pileus (pll'eus) n. [L. pileus, a felt 
cap.] The umbrella-shaped struc- 
ture of a mushroom (dot.), or of a 
jelly-fish (zoo/.). 

pilidium (pllid'ium) n. [Gk. pilidion, 
a small cap.] The characteristic 
helmet-shaped larva of Nemertines 

pilifer (pil'Ifgr) n. [L. pilus, hair ; 
ferre, to carry.] Part of the labrum 
of Lepidoptera (zoo!.). 

piliferous (pilif'grus) a. [L. pilus, 
hair ; ferre, to carry.] Bearing or 
producing hair (dto!.) ; appl. the 
outermost layer of a root or epi- 
blema which gives rise to root- 
hairs (oof.). 

pilose (pflos) a. [L. pilus, hair.] 

pilus (pl'lus). [L. fli/us, hair.] One 
of slender hair - like structures 
covering some plants (oof.). 

pinacocytes (pin'akoslts) n. plu. [Gk. 
pinax, a tablet ; kytos, hollow.] 
The flattened plate-like cells of the 
dermal epithelium of Sponges 

pincers, prehensile claws, as of 
lobster ; chelae of Insects ; cheli- 
cerae of Arachnids (zoo!.). 

pinealis (pine'alls) n. [L. pinea, a 
pine-cone.] An upgrowth from the 
roof of the midbrain of Vertebrates ; 
the pineal body or gland or eye. 

pinna (pln'a) n. [L. pinna, a feather.] 
A leaflet of a pinnate leaf (do/.) ; 
the outer ear ; a bird's feather or 
wing ; a fish-fin (zoo!.). 

pinnate (pin'at) a. [L. pinna, a 
feather.] Divided in a feathery 
manner; with lateral processes ; of 
a compound leaf, having leaflets 
on each side of an axis or midrib 

pinnatifld (pinat'ifid) a. [L. pinna, 
feather ; findere, to cleave.] Appl. 
leaves lobed about half-way to the 
midrib (fot.). 

pinnatilobate (plnat'ilo'bat) a. [L. 
pinna, feather ; Gk. lobos, a lobe.] 
With leaves pinnately lobed (oof.). 

pinnation (plna'shun) n. [L. pinna, 
feather.] Pinnate condition (boi.\ 

pinnatipartite (plnat'Ipar'tlt) a. [L. 
pinna, feather ; partitus, divided.] 
With leaves lobed three-quarters of 
the way to the midrib (oof.). 

pinnatiped (pinat'ipgd) a. [L. pinna, 
feather ; pes, foot.] Having lobed 
feet, as certain Birds. 

pinnatisect (ptnat'isekt) a. [L. pinna, 
feather ; sectus, cut.] With leaves 
lobed almost down to the base or 
midrib (dot.). 

pinnatodentate (plnat'odeVtat) a. [L. 
pinna, feather ; dens, tooth.] Pin- 
nate, with toothed lobes (dof.). 

pinnatopectinate (pfnat'opeVtlnat) a. 
[L. pinna, feather ; pecten, a comb.] 
Pinnate, with pectinate lobes (dof.). 

pinnlform (ptn'lform) a. [L. pinna, 
feather; forma, shape.] Feather- 
shaped or fin- shaped (dio!.). 

pinninervate (pln'IneVvat) a. [L. 
pinna, feather ; nervus, a sinew.] 
With veins disposed like parts of a 
feather (dof.). 

pinnule (pln'ul) n. [L. pinna, feather.] 
A secondary leaflet of a bipinnate 
leaf (dot.) ; in Crinoids, one of the 
side-branches, two rows of which 
fringe the arms (zoo!.). 

pinulus (ptn'ulus) n. [L. pinulus, a 
small fir.] A spicule resembling a 
fir-tree owing to the development 
of numerous small spines from one 
radial ray (zool.\ 





piscicolous (pisik'olus) a. [L. piscis, 
fish ; colere, to inhabit.] Living 
within fishes, as certain parasites 

pisciform (pis'iform) a. [L. piscis, 
fish ; forma, shape.] Shaped like 
a fish. 

piscivorous (pisiv'orus) a. [L. piscis, 
fish ; vorare, to devour!] Fish- 

pisiform (pl'siform) a. [L. pisum, a 
pea ; forma, shape.] Pea-shaped ; 
appl. a carpal bone (zool.). 
pisohamate (pi'soham'at) a. [L. 
pisum, pea ; hamus, a hook.] Appl. 
a ligament connecting pisiform and 
hamate bones (anat.). 
pisometacarpal (pl'somet'akar'pal) a. 
[L. pisum, pea ; Gk. meta, beyond ; 
L. carpus, wrist.] Appl. a ligament 
connecting the pisiform bone with 
the fifth metacarpal (anat.}. 
pistil (pTs'tll) n. [L. pistillum, a 
pestle.] The seed-bearing organ 
of a flower, consisting of ovary and 
stigma (bot.). 

pistillate (pis'tilat) a. [L. pistillum, 
a pestle.] Bearing pistils or female 
reproductive organs (bot.). 
pistillidium (pistilid'ium) n. [L. 
pistillum, a pestle.] The female 
sexual organ of Bryophytes, 
Pteridophytes, and Gymnosperms 

pistillody (pis'tllodi) n. [L. pistillum, 
a pestle ; Gk. eidos, resemblance.] 
The conversion of any organ of a 
flower into carpels (bot.). 
pistillum (ptstil'um) n. [L. pistillum, 
a pestle.] A mass of muscle in a 
chitinous tube in the aurophore of 
a medusoid colony (zool.). 
pit (pit) n. [h..S.pyt, a pit.] A de- 
pression formed in the course of 
cell-wall thickening in plant tissue 
(bot.} ; an embryonic olfactory 
depression (smb.}. 

pitcher (pit'sher) n. [L.L. picarium, 
a beaker.] A modification of a leaf 
for insect-catching purposes, as the 
pitcher-shaped leaf of Nepenthes 

pith (pith) n. [A.S./z'Ma, pith.] The 

medulla or central region of a 

dicotyledonous stem (bot.). 

pituitary (pitu'itari) a. [L. pituita, 

phlegm.] Appl. a' body or hypo- 

physis of the hypothalamus of the 
brain (anat.). 

pivot joint, a trochoid joint, or one 
in which the movement is limited 
to rotation (phys.). 

placenta (plasen'ta) n. [L. placenta, 
a flat cake.] The ovule-bearing 
part of the carpel (bot.) ; in eutherian 
Mammals, a double vascular spongy 
structure formed by interlocking of 
foetal and maternal tissue in the 
uterus, and in which maternal and 
foetal blood are in close proximity, 
allowing nutritive and respiratory 
elements to pass from the former to 
the latter by osmosis. 

placental (plasen'tal) a. [L. placenta, 
a flat cake.] Pert, a placenta or 
similar structure ; appl. Mammals 
which develop a placenta. 

placentate (plasen'tat) a. {L. placenta, 
a flat cake.] Having a placenta 
developed (biol,). 

placentation (plas'enta'shun) n. [L. 
placenta, a flat cake.] The manner 
in which seeds are attached to the 
pericarp, whether axile, central, 
marginal, or parietal (bot.). 

placentiferous, placentigerous, pla- 

placochromatic (plak'okromat'ik) a. 
[Gk. plax, a plate ; chroma, colour.] 
With plate-arrangement of chrom- 
atophores (cyt.). 

placoid (plak'oid) a. [Gk. plax, a 
plate ; eidos, resemblance.] Plate- 
like ; appl. the hard scales or dermal 
teeth on the external surface of 
Elasmobranchs (zool.). 

placula (plak'ula) n. \G\a.plax, plate.] 
A flattened blastula with small 
segmentation cavity, an embryonic 
stage of Urochords (emb.). 

plagiotropic (pla'jiotrop'ik) a. [Gk. 
plagios, oblique ; trope, a turning.] 
Obliquely inclined ; appl. roots and 
branches (bot.). 

plagiotropism (pla'jiot'rb'pizm) n. 
[Gk. plagios, oblique ; trope, a 
turning.] Tendency to incline 
from the vertical line (bot.). 

plagiotropous (pla'jiot'ropus) a. [Gk. 
plagios, oblique ; trope, a turning.] 
Obliquely inclined ; appl. the asym- 
metrical polar cap of Rhombozoa 

planiform (pla'niform) a. [L. planus, 




level ; forma, shape.] With nearly 
flat surface ; appl. certain articula- 
tion surfaces. 

plankton (plangk'tSn) n. [Gk. 
plangktos, wandering.] The animal 
and plant life floating through 
water, including animals with weak 
locomotory power (biol.}. 

planoblast (plan'oblast) n. [Gk. 
pianos, wandering ; blastos, bud.] 
A free-swimming hydroid individual 

Planogamete (plan'ogainef) n. [Gk. 
pianos, wandering; gamete, a 
spouse.] A ciliated motile proto- 
plast or microzoospore of Algae 

planont (plan'ont) n, [Gk. pianos, 
wandering.] The initial amoebula- 
stage of Neosporidia (zool.}. 

planta (plan'ta) n. [L. planta, sole of 
the foot.] The sole of the foot ; 
the first tarsal joint of Insects. 

plantar (plan' tar) a. [L. planta, sole 
of the foot.] Pert, the sole of the 
foot ; appl. arteries, ligaments, 
muscles, nerves, veins (anat.}. 

plantigrade (plan'tlgrad) a. [L. 
planta, sole of the foot ; gradus, a 
step.] Walking with the whole sole 
of the foot touching the ground. 

plantula (plan'tula) n. [L. plantula, 
a small sole.] The empodium or 
pulvillus of Insects (zool.}. 

planula (plan'ula) n. [L. planus, 
flat.] The ovoid young free- 
swimming larva of Coelenterates 

planum (plan'um) n. [L. planus, 
flat.] A plane or area ; appl. cer- 
tain cranial bone surfaces (anat.}. 

plasma (plaz'ma) n. [Gk. plasma, 
something formed.] The "liquid 
tissue " of body fluids through which 
leucocytes and corpuscles are dis- 
seminated ; protoplasm generally 

plasm a tic (plazmat'Ik) a. [Gk. 
plasma, something formed.] Pert. 
plasma ; protoplasmic (biol.}. 

plasmatoparous (plaz'matop'arus) a. 

Cik. plasma, something formed ; 
parere, to beget.] Developing 
a mycelium directly upon germina- 
tion instead of zoospores, as the 
grape mildew and other Plasmopara 

plasmocyte (plafmoslt) n. [Gk. 

plasma, something formed ; kytos, 

hollow.] A leucocyte (pkys.}. 
plasmodial (plazmo'dlal) a. [Gk. 

plasma, a mould ; eidos, form.] 

Pert, a plasmodium. 
plasmodiocarp (plazmo'dlokarp') n. 

[Gk. plasma, a mould ; eidos, form ; 

karpos, fruit] A modification of a 

ilasmodium in some slime Moulds 

plasmodium (plazmo'dlum) n. [Gk. 
plasma, a mould ; eidos, form.] A 
collection of amoeboid masses 
without nuclear fusion ; the naked 
protoplasm of Myxomycetes (biol.}. 

plasmogamy , plastogamy. 

plasmolysis (plazmol'isis) n. [Gk. 
plasma, a mould ; lysis, a loosing.] 
The withdrawal of water from plant 
protoplasm, causing contraction of 
cell walls (bot }. 

plasmosome (plaz'mosom) n. [Gk. 
plasma, a mould ; soma, body.] 
The true nucleolus ; cf. karyosome 

plasmotomy (plazmot'oml) n. [Gk. 
plasma, a mould ; tome, a cutting.] 
Division of a plasmodium by cleav- 
age into two or more multinucleate 
parts (biol.}. 

plasome (plas'om) n. [Gk. plasma, a 
mould ; soma, body.] An ultimate 
vital unit ; a biophore. See hypo- 
thetical units. 

plastic (plas'tik) a. [Gk. plastos, 
formed.] Formative ; appl. sub- 
stances used in forming or building 
up tissues or organs ; appl. force 
which gives matter definite form 

plastid (plas'tid) n. [Gk. plastos, 
formed.] A cell-body other than 
nucleus or centrosome (cyt.}. 

plastidogen organ, the axial organ 
of Echinoderms (zool.}. 

plastidule (plas'tldul) n. [G\i-plastos, 
formed.] The ultimate vital unit ; 
a plasome or biophore. See hypo- 
thetical units. 

plastin (plas'tln) n. [Gk. plastos, 
formed.] A substance found in the 
reticulum of cells (cyt.}. 

plastodynamia (plas'todlnam'ia) n. 
[Gk. plastos, formed ; dynatnis, 
power.] Plastic or formative force 




plastogamy (plastog'ami) n. [Gk. 
plastos, formed ; games, marriage.] 
Union of distinct protozoan indi- 
viduals with fusion of cytoplasm 
but not of nuclei (zool.}. 

plastral (plas'tral) a. [F. plastron, a 
breast-plate.] Pert, a plastron. 

plastron (plas'tron) n. [F. plastron, 
a breast-plate.] The ventral bony 
shield of Tortoises and Turtles ; 
some other corresponding struc- 
tures (zool.}. 

plate (plat) n. [L. platus, flat.] A 
flat, broad, plate-like structure or 
surface ; a lamina, scale, disc, etc. 

platydactyl (plat'idak'til) a. [Gk. 
platys, flat ; daktylos, a finger.] 
With flattened-out fingers and toes, 
as certain tailless Amphibians 

platysma (platiz'ma) n. [Gk. platysma, 
a flat piece.] A broad sheet of 
muscle beneath the superficial fascia 
of the neck (anat.}. 

plectonephridia (plek'tonefrid'ia) n. 
plu. [Gk.plektos, twisted ; nephros, 
kidney.] Nephridia of diffuse type 
formed of networks of fine excretory 
tubules lying on the body-wall and 
septa of certain Oligochaetes ; 
plectonephria, nephridia (zool.}. 

pleiocyclic (pll'osfk'llk) a. [Gk. pleion, 
more ; kyklos, circle.] Living 
through more than one cycle of 
activity, as a perennial plant (bot.}. 

pleiomerous (pliom'erus) a. [Gk. 
pleion, more ; meros, part.] Having 
more than the normal number of 
parts, as of petals or sepals (bot.}. 

pleiophyllous (plfoftTus) a. [Gk. 
pleion, more ; phyllon, leaf.] Having 
more than the normal number of 
leaves or leaflets (bot.}. 

pleiotaxy (pli'otak'si) n. [Gk. pleion, 
more ; taxis, arrangement.] A 
multiplication of whorls, as in 
double flowers (bot.}. 

pleomorphous (ple'6m6r'fus) a. [Gk. 
pleon, more ; morphe, form.] Poly- 
morphous ; having two or more 
distinct forms occurring in one life- 
cycle (biol.}. 

pleon (ple'on) n. [Gk. pleein, to sail.] 
The abdominal region of Crus- 
taceans (zool.}. 

pleopod (ple'opod) n. [Gk. pleein, to 
sail ; pous, foot.] An abdominal 

appendage or swimming -leg of 
Crustaceans (zool.}. 

plerocestoid (pler'oses'toid) n. [Gk. 
pleros, full ; kestos, girdle ; eidos, 
form.] A inetacestode, or sexless 
encysted stage of a cestoid worm 

plerome (pleYom) n. [Gk. pleroma, 
completion.] The core or central 
part of an apical meristem (bot.}. 

pleura (ploo/a) n. [Gk. pleura,_ a 
side.] A serous membrane lining 
the thoracic cavity and investing 
the lung (anat.}. 

pleural (ploor'al) a. [Gk. pleura, a 
side.] Pert, a pleura or pleuron ; 
as pleural ganglia (zool.}. 

pleuralia (ploora'lia) n. plu. [Gk. 
pleura, a side.] Defensive spicules 
scattered over the general surface 
of the body (zool.}. 

pleurapophysis (ploor'apofisls) n, 
[Gk. pleura, a side ; apo, from ; 
physis, growth.] A lateral verte- 
bral process or true rib (zool.}. 

pleurite (ploor'lt) n. [Gk. pleura, a 
side.] A pleuron. 

pleurobranchiae (ploor'obrang'kie) n. 
plu. [Gk. pleura, a side ; brangchia, 
gills.] Pleurobranchs, or gills 
springing from the lateral walls of 
the thorax of certain Arthropods 

pleurocarpous(ploor'6kar'pus) a. [Gk. 
pleura, a side ; karpos, fruit.] Appl. 
Mosses with fructification on lateral 
branches (bot.}. 

pleurocentrum (ploor'osen'triim) n. 
[Gk. pleura, a side ; L. centrum, a 
centre.] A lateral element of the 
centrum of many Fishes and fossil 
Amphibians (zool.}. 

pleurocerebral (ploor'6'seYebral) a. 
[Gk. pleura, a side ; L. cerebrum, 
brain.] Pert, pleural and cerebral 
ganglia, in Molluscs (zool.}. 

pleurodont (ploor'odont) a. [Gk. 
pleura, side ; odous, tooth.] Having 
teeth fixed by their sides to the 
lateral surface of the jaw ridge, as 
in some Lizards (zool.}. 

pleuron (ploor'on) n., pleura (ploor'a), 
plu. [Gk. pleuron, a side.] The 
external lateral pieces of the body 
segments of Arthropods ; the 
lateral extensions of Crustacean 
shells (zool.}. 



pleuropedal (ploo/oped'al) a. [Gk. 
pleura, a side ; L. pes, foot.] Pert. 
pleural and pedal ganglia of 
Molluscs (zoo/.), 

pleuroperltoneum (ploor'opeV- 
itone'um) n. [Gk. pleura, side ; 
peri, round ; teinein, to stretch.] 
Pleura and peritoneum combined, 
the body-lining membrane of 
animals without diaphragm (zoo/.). 
pleuropodiuxn (ploor'opo'dmm) n. 
[Gk. pleura, a side ; pous, foot.] 
A lateral glandular process of the 
abdomen of some Insects (zoo/.). 
pleurosteon (plooros'teon) n. [Gk. 
pleura, side ; osteon, bone.] The 
lateral process of the sternum in 
young Birds, afterwards the costal 
process (zoo/.). 

pleurotribe (ploor'otrib) a. [Gk. 
pleura, side ; tribein, to rub.] Appl. 
flowers whose anthers and stigma 
are so placed as to rub the sides of 
insects entering them, a device 
for securing cross-pollination (to/.). 
pleurovisceral (ploor'ovis'e'ral) a. 
[Gk. pleura, side ; L. viscera, in- 
testines.] Pert, pleural and visceral 
ganglia of Molluscs (zoo/.). 
plexlform (pleVstform) a. [L. plexus, 
interwoven ; forma, shape.] En- 
tangled or complicated ; like a 
network ; appl. layers of the retina 
plexifonn gland, the axial organ of 

Echinoderms (zoo/.). 
plexus (pleVsus) n. [L. plexus, inter- 
woven.] A network of interlacing 
blood-vessels or nerves (ana/.). 
plica (plfka) n. [L. plicare, to fold.] 
A fold of skin or membrane (ana/.). 
plicate (plik'at) a. [L. plicare, to 
fold.] Folded like a fan, as a leaf 
(to/.) ; folded or ridged (zoo/.). 
pliciform (plis'iform) a. [L. plicare, 
to fold ; forma, shape.] Resembling 
a fold ; disposed in folds, 
pluma (ploom'a) n. [L. pluma, a 
feather.] A contour feather of birds. 
plumage (ploom'aj) n. [L. pluma, 
feather.] The entire covering of 
feathers of a bird. 

plumate (ploom'at) a. [L. pluma, 
feather.] Plume-like in arrange- 

plume (ploom) n. [L. pluma, feather.] 
A feather, or feather-like structure. 

plumicome (ploomlkom) n. [L. 
pluma, feather ; coma, hair.] A 
spicule with plume-like tufts (zoo/.). 
plumicorn (ploom'IkSrn) n. [L. 
pluma, feather ; cornu, horn.] A 
horn-like tuft of feathers on a bird's 

plumigerous (ploomij'e'rus) a. [L. 
pluma, feather ; gerere, to carry.] 

plumiped (ploom'Tpe'd) n. [L. pluma, 
feather ; pes, foot.] A bird with 
feathered feet. 

plumose (ploom'os) a. [L. pluma, 
feather.] Feathery; having feathers; 
feather-like ; appl. a type arrange- 
ment of skeletal fibre in Sponges, 
plumula, a plumule, 
plumulaceous, plumulate. 
plumulate (ploom'ulat) a. [L. plum- 
ula, a small feather.] Downy ; with 
a downy covering. 

plumule (ploom'ul) n. [L. plumula, 
a small feather.] A primary bud 
which develops the primary axis of 
a stem (to/.) ; the androconia of 
numerous butterflies ; a down- 
feather (zoo/.). 

pluriaxial (ploor'iak'slal) a. [L. plus, 
more ; axis, axle.] Having flowers 
developed on secondary shoots 

plurilocular (ploor'Ilfik'ular) a. [L. 
plus, more ; loculus, a little place.] 
Having two or more loculi. 
pluripartite (ploor'ipar'tit) a. [L. 
plus, more ; ftartitus, divided.] 
With many divisions, lobes, or 

pluriserial (ploor'fse'rTal) a. [L. plus, 
more ; series, a row.] Arranged in 
two or more rows. 

plurivalent (plooriv'alfint, ploor'Iva'- 

iSnt) a. [L. plus, more ; valere, to be 

worth.] Appl. a chromatin-rod with 

more than one chromosome (cyt.). 

pluteal (ploot'eal) a. [L. pluteus, a 

shed.] Pert, a pluteus. 
pluteus (ploot'eus) n. [L. jtluteus, a 
shed.] The free-swimming larva 
of Echinoids and Ophiuroids (zool.). 
pneumatic (numat'lk) a. [Gk.pneuma, 
air.] Appl. bones of birds pene- 
trated by canals connected with 
the respiratory system (zoo/.). 
pneumaticity (numatlsTtf) n. [Gk. 
pneuma, air.] State of having air 




cavities, as in the bones of flying 
birds (zool.). 

pneumatized (nu'matlzd) a. [Gk. 
pneuma, air.] Furnished with air 

pneumatocyst (nu'matosTst) n. [Gk. 
pneuma, air ; kystis, a bladder.] 
The air-bladder or swim-bladder of 
Fishes (zool^j. 

pneuinatophore (nu'matofor) n. [Gk. 
pneuma, air ; pherein, to bear.] The 
air-sac or float of Siphonophores 
(zool.} ; an air-bladder of marsh or 
shore-plants (hot.). 

pneumatopyle (nu'matopll) n. [Gk. 
pneuma, air ; pyle, gate.] One of 
the pores of a pneumatophore, 
opening above to the exterior in 
certain Siphonophores (zool.}. 

pneumogastric (nu'mogas'trik) a. 
[Gk. pneuma, air ; gaster, stomach.] 
Appl. the tenth cranial nerve, 
supplying heart, lungs, and viscera 

pneumotaxis (nu'motak'sis) n. [Gk. 
pneuma, air ; taxis, arrangement.] 
Reaction to the stimulation of 
carbon dioxide in solution ; cf. 
aerotaxy (phys.\ 

pod (pod) n. [M.E. pod, a bag.] A 
superior, one-celled, one- or many- 
seeded fruit of two valves ; a husk 

podal (pS'dal) a. [Gk. pous, a foot.] 
Pert, feet ; j>edal. 

podeon (po'deSn) n. [Gk. pous, foot.] 
The petiole or slender middle part 
of the abdomen of Hymenoptera 
uniting propodeon and metapodeon 

podetiiform (pode'shnform) a. [Gk. 

pous, foot ; L. forma, shape.] Re- 

sembling a podetium (hot.). 
podetium (pode'shium) n. [Gk. pous, 

foot.] A stalk-like elevation from 

the thallus of some Lichens (bot.\ 
podeum, a podeon. 
podex (po'dgks) n. [L. podex, rump.] 

The region about the anus. 
podlcal (pSd'ikal) a. [L. podex, rump.] 

In the anal region ; appl. a pair of 

small hard plates beside the anus 

of Arthropods (zool.~). 
podite (pod'It) n. [Gk. pous, foot.] 

A Crustacean walking leg. 
podium (po'dium) n. [Gk.pous, foot.] 

A foot or footlike structure (biol.\ 

podobranchiae (p5dobrang'kle) n. plu. 
[Gk. pous, foot ; brangchia, gills.] 
Podobranchs or foot-gills, springing 
from the coxopodites of the thoracic 
appendages of certain Arthropods 

podocephalous (podokefalus, -s6f-) 
a. [Gk. pous, foot ; kephale, head.] 
Having a head of flowers on a long 
stalk (&?/.) 

podoconus (pod'b'ko'nus) n. \G\a.pous, 
foot ; konos, cone.] A conical mass 
of endoplasm connecting the central 
capsule with the disc of Sarcodina 

podocyst (pod'osist) n. [Gk. pous, 
foot ; kystis, bladder.] A pedal 
sinus or caudal vesicle in certain 
Gasteropods (zool.}. 

pododerm (pod'oderm) n. [Gk. pous, 
foot ; derma, skin.] The dermal 
layer of a hoof, within the horny 
layer (zool^). 

podogynium (pod'qjm'ium) n. [Gk. 
pous, foot ; gyne, a female.] A stipe 
supporting the gynoecium (dot.*). 

podomere (pod'omer) n. [Gk. pous, 
foot ; meros, part.] A limb segment 
of Arthropods (zool.}. 

podophthalmite (pod'ofthal'mlt) n. 
[Gk. pous, foot ; ophthalmos, eye.] 
In Crustaceans, the eyestalk seg- 
ment farthest from the head (zool.~). 

podotheca (pSd'othe'ka) n. [Gk. 
pous, foot ; theke, a -box.] A foot 
covering, as of Birds or Reptiles. 

pogonion (pogo'nion) n. \G\a.pogonion, 
little beard.] The most prominent 
point of the chin as represented on 
the mandible (anat.}. 

poikilothennal (poik'ilothgr'mal) a. 
[Gk. poikilos, various ; thermos, 
heat.] Appl. cold-blooded animals, 
or those whose temperature varies 
with that of thesurroundingmedium; 
cf. homolothermal (phys.\ 

poikilothermous, poikilothermal. 

poisers, halteres, which see. 

polar (po'lar) a. [Gk. polos, a pivot.] 
In the region of the end of an 
axis ; at a pole. 

polar body, one of two cells divided 
off from the ovum during matura- 
tion, before the germ-nuclei fuse 

polar nuclei, a nucleus remaining 
at each end of an angiosperm em- 




bryo, which later form the second- 
ary nucleus (dot.). 

polar plates, two narrow ciliated 
areas produced in the transverse 
plane, part of the equilibrium ap- 
paratus of certain Coelenterates 

polar rays, astral rays, as opp. 
spindle-fibres (cyt.). 

polar rings, two ring-shaped cyto- 
plasmic masses near the ovum poles 
formed after union of the germ- 
nuclei (cyt.}. 

polarity (polarTti) n. [Gk. polos, a 
pivot.] The tendency of plants to 
develop from the poles, roots 
downwards, stems upwards (bot.) ; 
the tendency of any ovum to place 
itself with its axis corresponding 
to that of the mother (emb.). 

pole plates, the end-plates or achro- 
matic masses at the spindle poles 
in Protozoa mitosis (cyt.\ 

Polian vesicles, interradial vesicles 
opening into the ring-vessel of the 
ambulacral system of most Star- 
fishes and Holothurians (zool.). 

polioplasm (pol'Ioplazm) n. [Gk. 
polios,gray ; plasma, form.] Spongio- 

pollen (pol'6n) n. [L. fallen, fine 
flour.] The male fertilizing element 
of seed plants (&?/.). 

pollen tube, a tubular process de- 
veloped from pollen grains after 
attachment to the stigma (hot.). 

pollex (pol'gks) n. [L. pollex, thumb.] 
The thumb, or innermost digit of 
the normal five in the anterior 
limb (zool.}. 

pollination (pSl'fnashun) n. [L. 
pollen, fine flour.] Fertilization in 
flowers ; transference of pollen from 
stigma to ovule (&>/.). 

polliniferous (pSl'Inlfgrus) a. [L. 
pollen, fine flour ; ferre, to carry.] 
Pollen-bearing (dot.} ; adapted for 
transferring pollen (zool.\ 

pollinium (polin'Ium) n. [L. pollen, 
fine flour.] An agglutinated pollen 
mass of Orchids and some other 
plants (hot.}. 

pollinodium (pol'ino'dlum) n. [L. 
pollen, fine flour ; Gk. eidos, form.] 
A club-shaped branch of mycelium, 
the antheridium of certain Fungi 

pollinoid (pol'moid) n. [L. pollen, 
fine flour ; Gk. eidos, form.] A 
male gamete or spermatium (bot,\ 

polocytes (po'loslts) n. plu. [Gk. 
polos, axis ; kytos, hollow.] Polar 
bodies (cyt.). 

polyadelphous (pol'iadeTfus) a. [Gk. 
polys, many ; adelphos, brother.] 
Having stamens united by filaments 
into more than two bundles (&?/.). 

polyandrous (pol'Ian'drus) a. [Gk. 
polys, many; andros, male.] Having 
twenty or more stamens (bot.). 

polyandry (pSl'ian'drl) n. [Gk. polys, 
many ; andros,* male.] Condition 
of a female consorting with several 
males ; as in some Fishes (biol.\ 

polyarch (p811ark) a. [Gk. polys, 
many ; arche, beginning.] Appl. 
a root having many xylem bundles 
united to form a plate in wood 
tissue (bot.). 

polyaxon (pol'Iak'sSn) n. [Gk. polys, 
many ; axis, an axis.] A type of 
spicule laid down along numerous 
axes (zool.}. 

polycarp (pol'ikarp) n. [Gk. polys, 
many ; karpos, fruit.] One of the 
gonads of some Ascidians dis- 
tributed over the inner surface of 
the mantle (zool.}. 

polycarpeUary (pdl'ikarpeTari) a. 
[Gk. Polys, many ; karpos, fruit] 
With compound gynoecmm (bot.). 

polycarpic, polycarpous. 

polycarpous (pol'ikar'pus) a. [Gk. 
polys, many ; karpos, fruit.] With 
numerous carpels ; appl. perennials 

polycercous (pSl'fseVkus) a. [Gk. 
polys, many ; kerkos, tail.] Appl. 
bladderworms developing several 
cysts, each with a head (zool.). 

polychasium (p8rika.'zium) n. [Gk. 
polys, many ; chasis, division.]" A 
cymose branch system when more 
than two branches arise about the 
same point (&?/.). 

polycotyledon (pSl'lkotlle'don) . 
[Gk. Polys, many ; kotyledon, a 
hollow vessel.] A plant with more 
than two embryo lobes (&>/.). 

polycotyledonary (pSl'ikStlle'donarl) 
a. [Gk. polys, many ; kotyledon^ 
a hollow vessel.] Having the 
placenta in many divisions or 
cotyledons (zool.). 




polycotyledonous (pol'ikotile'donus) 
a. [Gk. polys, many ; kotyledon, 
a hollow vessel.] Having more 
than two cotyledons or seed lobes, 
as the fir embryo (bot.). 

polycotyledony (pol'ikottle'doni) n. 
[Gk. polys, many ; kotyledon, a 
hollow vessel.] A great increase 
in the number of cotyledons (hot.}. 

polycrotism (polik'rotizm) n. [Gk. 
polys, many ; krotos, a beating.] 
Condition of having several second- 
ary elevations in the pulse curve 

polycyclic (pol'isik'lik) a. [Gk. polys, 
many ; kyklos, a circle.] Having 
many whorls or ring structures 

polycystid (pol'ists'tid) a. [Gk. polys, 
many ; kystis, a bladder.] Septate ; 
partitioned off (biol.}. 

polydactyllsm (pol'idak'tilizm) . 
\Gk.polys, many ; daktylos, a finger.] 
Condition of having an excessive 
number of fingers or toes (zool.). 

polyembryony (pSl'igm'brloni) n. 
[Gk. polys, many ; embryon, a 
foetus.] Instance of a zygote 
giving rise to more than one 
embryo (bot.). 

polyenergid (pol'ie'n'e'rjid) a. [Gk. 
polys, many ; energos, active.] 
Appl. nuclei with more than one 
centriole (cyt.). 

polygamous (polig'amus) a. [Gk. 
polys, many ; gamos, union.] Bear- 
ing male, female, and hermaph- 
rodite flowers (bot.) ; consorting 
with more than one mate (zool.}. 

polygamy (polig'ami) n. [Gk. polys, 
many ; gamos, union.] Condition 
of having staminate, pistillate, and 
hermaphrodite flowers upon the 
same individual (bot.) ; condition 
of having more than one mate at 
a time (zool.}. 

polygenetic (pol'ijenet'ik) a. [Gk. 
polys, many ; genesis, descent.] 
Derived from two sources ; sexually 
produced (biol.}. 

polygenic, polygenetic. 

polygoneutic (pol'igonu'tik) a. [Gk. 
polys, many ; goneuein, to beget.] 
Rearing more than one brood in a 
season (zool.). 

polygynoecial (pol'Ijine'shlal) a. [Gk. 
polys, many ; gyne, woman ; oikos, 

house.] Having multiple fruits 
formed by united gynoecia (bot.}. 

polygynous (polij'inus) a. [Gk. polys, 
many ; gyne, female.] Consorting 
with more than one female at a 
time (zool} ; with many styles (bot.}. 

polykaryon (pSl'ikar'Ion) n. [Gk. 
polys, many ; karyon, nut.] A 
polyenergid nucleus ; a nucleus 
with more than one centriole (cyt.). 

polymastigote (porimas'tlgot) a. 

eik. polys, many ; mastix, whip.] 
aving flagella arranged in a tuft 

polymastlsm (pollmas'tlzm) n. [Gk. 
polys, many ; mastos, breast.] Oc- 
currence of more than the normal 
number of mammae. 

polymerisation (polimSrlzashun) n. 
[Gk. polys, many ; meros, part.] 
The uniting together of a number 
of molecules in a liquid with 
chemical combination (phys.). 

polymerous (polim'e'rus) a. [Gk. polys, 
many ; meros, part.] Consisting of 
many parts or members (bot.). 

polymorphism (pol'imor'fizm) n. [Gk. 
polys, many ; morphe, form.] Oc- 
currence of different forms of 
individuals in the same species ; 
occurrence of different forms, or 
different forms of organs, in the 
same individual at different periods 
of life (biol.). 

polymorphonuclear (pol'imor'fonu'- 
klear) a. [Gk. polys, many ; morphe, 
form ; L. nucleus, kernel.] Appl. 
leucocytes with multipartite nuclei 
connected by fine threads of 
chromatin (cyt.). 

polymorphous (pol'imor'fus) a. [Gk. 
polys, many ; morphe, form.] As- 
suming various forms or shapes 

polynucleate (pol'inu'kleat) a. [Gk. 
polys, many ; L. nucleus, kernel.] 
Containing several or many nuclei 

polyp (pol'ip) n. [L. polypus, polyp.] 
A simple Actinozoon, as a sea- 
anemone ; a separate zooid of an 
Actinozoan colony (zool.). 

polyparium (pol'Ipa'rium) n. [L. 
polypus, polyp.] The common base 
and connecting tissue of a colony 
of polyps (zool). 

polypary, a polyparium. 




polypetalous (pol'ipeYalus) a. [Gk. 
Polys, many \petalon, leaf.] Having 
separate, free, or distinct petals 

polyphagous (pollf'agus) a. [Gk. 
polys, many ; phagein, to eat.] 
Eating many and various kinds of 
food ; of Sporozoa, passing different 
phases of life-history in different 
cells (biol.}. 

polyphyletio (pSl'IflleVik) a. [Gk. 
polys, many ; phylon, race.] Con- 
vergent, as appl. a group ; com- 
bining characteristics of more than 
one ancestral type through in- 
dependent acquisition, (biol.}. 

polyphyllous (p81'ifil'us) a. [Gk. 
Polys, many ; phyllon, leaf.] Many- 
leaved (bot.}. 

polyphyodont (p81'ifl'6dont) a. [Gk. 
pofyphyes, manifold ; odous, tooth.] 
Having many successive sets of 

polypide (pol'fpld) n. [L. polypus, a 
polyp.] An individual or person 
of a zooid colony (zoo/.}. 

polypite, a polypide. 

polyplastic (pol'iplas'tlk) a. [Gk. 
Polys, many ; plastos, formed.] Cap- 
able of assuming many forms (biol.}. 

polypod (p51'tp8d) a. [Gk. polys, 
many ; POUS, foot.] Furnished 
with many feet or legs. 

polypoid (poHpoid) a. [L. polypus, 
polyp ; Gk. eidos, form.] Polyp- 

polyprotodont (pSl'Ipro'todont) a. 
[Gk. Polys, many ; protos, first ; 
odous, tooth.] With four or five 
incisors on each side of the upper 
jaw, and one or two fewer on the 
lower as in the Tasmanian Devil 

polyrhizal (pSl'iri'zal) a. [Gk. polys, 
many ; rhiza, root.] With many 
roots or rootlets (dot.}. 

polysepalous (pSl'Isep'alus) a. [Gk. 
polys, many ; sepalon, a sepal.] 
Having free or distinct sepals (dot.}. 

polyslphonic (pol'isiffin'lk) a. [Gk. 
Polys, many ; siphon, a tube.] Appl. 
a hydromedusa stem consisting of 
several hydrocauli bound together 


polysomitic (poTlsomlt'lk) a. [Gk. 
Polys, many ; soma, body ; temnein, 
to cut.] Having many body- 

segments ; formed from fusion of 
the primitive body segments (zool.}. 

polyspermous (pol'ispeYmus) a. [Gk. 
polys, many ; sperma, seed.] Having 
many seeds (bot.}. 

polyspenny (poTispeYml) n. [Gk. 
polys, many ; sperma, seed.] Entry 
of several sperms into one ovum 

polysporous (poTlspo'rus) a. [Gk. 
polys, many ; sporos, seed.] Many- 
seeded ; many-spored (bot.}. 

polystachyous (pSl'IstakKus) a. [Gk. 
polys, many ; stachys, an ear of 
corn.] With numerous spikes (bot.}. 

polystelic (pol'isteTlk) a. [Gk. polys, 
many ; stele, a post.] With several 
steles (bot.}. 

polystely (p5ttste'H) n. [Gk. polys, 
many ; stele, a post.] Arrange- 
ment of axial vascular tissue in 
several steles, each containing 
more than one vascular bundle 

polystemonous (pfil'Istgrn'onus) a. 
[Gk. polys, many; stemon, a warp.] 
Having the stamens more than 
double the number of petals or 
sepals (bot.}. 

polystichous (pSl'Istlk'us) a. [Gk. 
polys, many ; stichos, a row.] 
Arranged in numerous rows or 

polystomatous (pSftstSm'atus) a. 
[Gk. Polys, many ; stoma, mouth.] 
Having many pores, mouths, or 
openings; many-mouthed, as Disco- 
medusae and Sponges (zool.}. 

polystomium (pfil'isto'mium) n. [Gk. 
polys, many ; stoma, mouth.] A 
suctorial mouth of Discomedusae 

polystylar (pSl'Istflar) a. [Gk. polys, 
many ; stylos, pillar.] Many- 
styled (bot.}. 

polysymmetrlcal (pSl'IsImeYrikal) a. 
[Gk. polys, many ; syn, with ; metron, 
measure.] Divisible through several 
planes into bilaterally symmetrical 
portions (boi.}. 

polythalamous (pollthal'Smus) a. 
[Gk. polys, many ; thalatnos, a 
chamber.] Aggregate or collective, 
as appl. fruits (bot.} ; appl. shells 
made up of many chambers formed 
successively (zool.}. 

polythely (pol'fthe'lT) n. [Gk. polys, 




many ; thele, a nipple.] Poly- 

polytocous (polit'okus) a. [Gk. polys, 
many ; tokos, offspring.] Prolific. 

polytomous (p81it'6mus) a. [Gk. 
polys, many ; tome, a cutting.] 
Having more than two secondary 
branches (bot.). 

polytrichous (pol'itrik'us) a. [Gk. 
polys, many ; thrix, hair.] Having 
the body covered with an even 
coat of cilia, as certain Infusorians 

polytrochal (pol'itro'kal, pollt'rokal) a. 
[Gk, polys, many ; trochos, wheel.] 
Having several circlets of cilia 
between mouth and posterior end, 
as in certain Annulates (zool.). 

polytrochous, polytrochal. 

polytrophic (pol'itrofik) a. [Gk. 
polys, many ; trophe, nourishment.] 
Nourished by more than one organ- 
ism or substance (biol.). 

polyzoarium (p51'iz6a'riurn) n. [Gk. 
polys, many ; zoon, animal.] The 
skeletal system of a Polyzoan 
colony ; the colony itself (zool.). 

polyzoic (pol'izo'ik) a. [Gk. polys,;, 
many ; zoon, animal.] Appl. a 
colony of many zooids ; appl. a spore / 
containing many sporozoites (zool-.). ' 

pome (pom) n. [L. pomum, apple.] 
An inferior, indehiscent, two or 
more celled fleshy fruit (bot.). 

pomum Adami, the prominent ridge 
of the thyroid cartilage in the front 
of the neck, more pronounced in 
males (anat.). 

pons (ponz) n. [L. pans, bridge.] A 
structure connecting two parts, as 
the pons Varolii of the cerebellum 

pontal, pontic, pontile, pontlne, 
pert, a pons or the pons Varolii 

ponticulus (p5ntik'ulus) n. [L. ponti- 
culus, a small bridge.] A vertical 
ridge on the auricular cartilage 

popliteal (pSplIt'eal, pop'lite'al) a. 
[L. poples, the ham.] Pert, the 
region behind and above the knee- 
joint ; appl. artery, glands, nerve, 
vein, muscle (anat.). 

pore (por) n. [Gk. poros, channel.] 
A minute opening or interstice, as 
of the skin, of a stone. 

porlcidal (po'risi'dal) a. [Gk. poros, 
channel ; L. caedere, to cut.] De- 
hiscing by valves or pores, as the 
poppy order (bot.'). 

poriferous (porif'grus) a. [Gk. poros, 
channel ; L. ferre, to bear.] Fur- 
nished with numerous openings or 

poriform (po'riform) a. [Gk. poros, 
channel ; L. forma, shape.] Re- 
sembling a pore. 

porocyte (po'roslt) n. [Gk. poros, 
channel ; kytos, hollow.] A per- 
forated cell of Porifera (zool.). 

porogam (po'rogam) n. [Gk. poros, 
channel ; gamos, union.] A plant 
whose pollen-tube enters the ovule 
by the micropyle ; opp. chalazogam 

porogamy (porog'a.mi) n. \Gk. poros, 
channel ; gamos, union.] Entrance 
of a pollen-tube into the ovule by 
the micropyle to secure fertilization 

porophyllous (po'rofil'us) a. [Gk. 
poros, channel ; phyllon, leaf.] 
Appl. leaves with numerous trans- 
^ parent spots (bot.). 

porta (por^ta) n. [L. porta, a gate.] 
A gate-like structure, as the trans- 
verse fissure of the liver (anat.). 

portal (portal) a. [L. porta, gate.] 
Appl. a system of veins draining 
the abdominal part of the alimentary 
canal, spleen, pancreas, and gall- 
bladder (anat.). 

portio (po/tio, por'shio) n. [L.portio, 
portion.] A part or portion of a 
nerve, blood-vessel, etc. (anat.). 

postabdomen (post'a.bdo'me'n) n. [L. 
post, after ; abdomen, belly.] In 
Scorpions, themetasoma or posterior 
narrower five segments of the 
abdomen (zool.). 

postanal (pSsta'nal) a. [L. post, after ; 
anus, vent.] Situated behind the 
anus (zool.). 

postaxial (postak'slal) a. [L. post, 
after ; 'axis, axle.] On the posterior 
side of the axis ; as on the fibular 
side of the leg (anat.). 

postbranchial (postbrang'kial) a. [L. 
post, after ; Gk. brangchia, gills.] 
Behind the gill-clefts ; appl. a 
structure arising in the pharynx 

postcardinal (postkar'dinal) a. [L. 




post, after ; Gk. kardia, heart.] 
Behind the region of the heart ; 
appl. a dorsal vein (anat.}. 

postcava (postka'va) n. [L. post, 
after ; cavus, hollow.] The inferior 
or dorsal vena cava of vertebrates 
above fishes ; the postcaval vein 

postcentral (postsgn'tral) a. [L. post, 
after ; centrum, centre.] Behind 
the central region ; appl. a cerebral 
sulcus (anat.}. 

postcentrum (postsSn'trum) n. [L. 
post, after ; centrum, centre.] The 
posterior part of the vertebral 
centrum of certain vertebrates 

postclavicle (postkl&v'ikl) n. [L. 
post, after ; claviculum, a small 
key.] A membrane bone occurring 
in the shoulder girdle of some 
higher Ganoids and Teleosts (zool.}. 

postclitellian (post'kliteTian) a. [L. 
post, after ; clitellae, a pack-saddle.] 
Situated behind the clitellum 

postcllval (postkllVal) a. [L. post, 
after ; clivus, a hill.] Appl. 
fissure behind the clivus oflti 
cerebellum (ana&. 

postclypeus (po^tklip'eus) n. 
post, after ; cfypeus, shiel 
posterior part of the cly 
Insect (zool.}. 

postdicrotic (post'dlkrSt'ik) a. [L. 
Post, after ; Gk. dis, twice ; krotein, 
to beat.] Appl. a secondary wave 
of a pulse, or that succeeding the 
dicrotic (phys.}. 

postembryonic (post'e'mbrTSn'flc) a. 
[L. post, after ; Gk. embryon, a 
foetus.] Pert, the age succeeding 
the embryonic (biol.}. 

posterior (poste'rlor) a. [L. posterior, 
later.] Situated behind or dorsally ; 
behind the axis ; superior or next 
the axis (bot.). 

posterolateral (pos'tgrolat'eral) a. 
[L. posterior, later ; latus, side.] 
Placed posteriorly and towards the 
side ; appl. arteries (anat.). 

posteromedlal (pos'tfirome'dt&l) a. 
[L. posterior, later ; medius, middle.] 
Placed posteriorly and medianly ; 
appl. arteries (anat.}. 

postfrontal (postfrun'tal) a. [L. post, 
after ; frons, forehead.] Appl. a 

bone occurring behind the orbit of 
some vertebrates, articulating with 
the frontal (zool.). 

postfurca (postfurTca) n. [L. post, 
after ; furca, fork.] A posterior 
sternal furca of an Insect (zool.). 

postganglionic (post'gang'gllfin'ik) a. 
[L. post, after ; Gk. gangglion, 
tumour.] Appl. fibres that leave 
the ganglion ; cf. preganglionic 

postglenoid (postgle'noid) a. [L. 
post, after ; Gk. glene, socket.] 
Behind the glenoid fossa ; appl. 
a small process (anat.). 

posthepatic (post'hepat'ik) a. [L. 
post, after ; hepar, liver.] Appl. 
the latter part of the alimentary 
canal, that from the liver to the 
end (emb.). 

posticous (pos'tlkus) a. [L. posticus, 
behind.] On the outer or posterior 
surface ; extrorse (biol.). 

postminimus (postmm'imus) n. [L. 
post, after ; minimus, smallest.] A 
rudimentary additional digit oc- 
i--Ji occasionally in Amphibia 


rer ; nodulus, a small knot.] 
a cerebellar fissure between 
lule and uvula (anat.). 

postorbltal (posto/bltil) a. [L. post, 
after ; orbis, circle.] Behind the 
orbit ; appl. a bone forming part 
of the posterior wall of the orbit 

postotic (postotlk) a. [L. post, after ; 
Gk. ous, ear.] Behind the ear ; 
appl. a system of nerves (anat.). 

postparletal (post'parfgtal) a. [L. 
post, after ; paries, wall.] Appl. 
paired bones sometimes occurring 
between parietals and interparietals 

postpatagium (post'pata'jtum) n. [L. 
post, after ; patagiutn, border.] In 
Birds, a small fold of skin extending 
postaxially between upper arm and 
trunk (zool.). 

postpermanent (postpSr'manfint) a. 
[L. post, after ; permanens, remain- 
ing.] Appl. traces of a dentition 
succeeding the permanent in man. 

postpubic (postpu'blk) a. [L. post, 
after ; pubis, mature.] At the 
posterior end of the pubis ; appl. 




processes of the pubis parallel to 
the ischium (zool.}. 

postpyramidal (post'piram'Tdal) a. 
[L. post, after ; pyramis, pyramid.] 
Behind the pyramid ; appl. a cere- 
bellar fissure (anat.}. 

postscutellum (post'skuteTum) n. 
[L. post, after ; scutellum, a small 
shield.] A projection under the 
mesoscutellar lobe of Insects, the 
base of the mesophragma (zool.}. 

postsphenoid (postsfe'noid) n. [L. 
Post, after ; Gk. sphen, wedge.] The 
posterior part of the sphenoid 

post-temporal (post-tSm'poral) a. [L. 
post, after ; temporalis, temporary.] 
Behind the temporal bone ; appl. 
bone and fossa (anat.}. 

post-trematic (p5st-tremat'lk) a. [L. 
post, after ; Gk. trema, a hole.] 
Appl. nerves running in the 
posterior wall of the first gill cleft 
to the pharynx (zool.}. 

postzygapophysis (post'zlg&pof'isis) n. 
[L. post, after ; Gk. zygon, yoke ; 
apo, from ; physis, growth.] An 
articular process on the posterior 
face of the neural arch for articula- 
tion with the succeeding vertebra 

potential (potgn'sh&l) a. [L. potens, 
powerful.] Latent, as appl. char- 
acteristics (biol.}. 

pouch (powch) n. [O.Y.pouche, bag.] 
A bag-like structure ; a sac or 
bladder, as the pharyngeal pouches 
(emb.} ; a marsupial pouch (zool.} 
a pod (bot.}. 

powder-down feathers, those which 
do not develop beyond the early 
stage, and which disintegrate at 
the tip into powder (zool.}. 

praeabdomen (pra'-, pre'abdo'mgn) n. 
[L. prae, before ; abdomen, belly.] 
The anterior, broader part of the 
abdomen of Scorpions (zool.}. 

praeauricular (pra'-, pre'orik'ular) a. 
[L. prae, before ; auricula, a small 
ear.] Appl. a sulcus at the anterior 
part of the auricular surface of the 
hip-bone (anat.}. 

praeaxial (pra-, preak'sial) a. [L. 
prae, before ; axis, axle.] On the 
anterior border or surface. 

praecentrum (pra-, presen'trum) n. 
[L. prae, before ; centrum, centre.] 

The anterior part of the vertebral 
centrum of certain lower vertebrates 

praecoces (pra-, preko'sez) n. phi. 
[L. prae, before ; coquere, to cook.] 
Newly-hatched birds able to take 
care of themselves ; cf. altrices 

praecostal (pra-, prekos'tal) a. [L. 
prae, before ; costa, rib.] Appl. 
short spurs on the basal portion of 
the hind wing of Lepidoptera (zool.}. 

praecmral (pra-, prekroor'al) a. [L. 
prae, before ; crus, leg.] On the 
anterior side of leg or thigh (anat.}. 

praecuneus (pra-, preku'neus) n. [L. 
prae, before ; cuneus, wedge.] The 
quadrate lobe of the cerebrum 

praemaxilla (pra'-, pre'maksil'a) n. 
[L. prae, before ; maxilla, jaw.] 
The anterior portion of the upper 
jaw ; the os incisivum (anat.}. 

praemorse (pra'-, pre'mors) a. [L. 
praemorsus, bitten off.] With 
irregular and abrupt termination, 
as if bitten off (bot.}. 

praeoccipital (pra'-, pre'oksip'Ttal) a. 
[L. prae, before ; occiput,, back of 
the head.] Appl. an indentation 
or notch anterior to the occipital 
pole of the cerebral hemispheres 

praeoral (pra-, preo'ral) a. [L. prae, 
before ; os, mouth.] Pert, the part 
of the body of a larva anterior to 
the mouth ; appl. process, loop, 
lobe, ciliated rings (zool.}. 

praepubic (pra-, prepu'bik) a. [L. 
prae, before ; pubes, mature.] On 
the anterior part of the pubis : 
appl. the elongated processes of 
the pubis of certain vertebrates 

praepuce (pra'-, pre'pus) n. [L. prae- 
putium, the foreskin.] That part 
of the integument of the penis 
which leaves the surface at the 
neck and becomes folded upon 
itself; the foreskin. 

praeputial (pra-, prepu'shtal) a. [L. 
praeputium, the foreskin.] Pert. 
the praepuce ; appl. glands, sac 

praeputium, the praepuce. 

praescutum (pra-, presku'tum) n. 
[L. prae, before ; scutum, shield.] 




The anterior part of the notum of 
an insect thoracic ring (zool.}. 

praesphenoid (pra-, presfe'noid) n. 
[L. prae, before ; Gk. sphen, wedge.] 
The anterior part of the sphenoid 

praesternal (pra-, presteYnal) a. [L. 
prae, before ; sternum, breast-bone.] 
Appl. the jugular notch, on the 
superior border of the sternum 

preaxlal (preak'slal) a. [L. prae, 
before ; axis, axle.] In front of 
the axis. 

precava (preka'va) n. \L..prae, before ; 
cavus, hollow.] The anterior vena 
cava ; the precaval vein (zool.). 

precentral (presen'tral) a. [L. prae, 
before ; centrum, centre.] An- 
teriorly to the centre ; appl. a 
sulcus parallel to the central sulcus 
of the cerebrum (anat.~). 

prechordal (prekor'dal) a, [L. prae, 
before ; Gk. chorde, a cord.] An- 
teriorly to the notochord or spinal 
cord ; appl. part of the base of the 
skull (emb.\ 

precipitin (preslp'ltln) n. \L.praeceps, 
headlong.] A precipitate developed 
in blood serum (phys.). 

preclival (preklfval) a. [L. prae, 
before ; clivus, hill.] Appl. a 
fissure in front of the clivus of the 
cerebellum (anat.~). 

precoracoid (prekor'akoid) . [L. 
prae, before ; Gk. korax, crow.] 
An anterior ventral bone of the 
pectoral girdle of higher vertebrates 

predelineation (pre'dellnea'shun) n. 
[L. prae, before ; de, down ; linea, 
a line.] Formation and individual- 
ization of the various physiological 
molecules in definite areas and 
substances of the undevelopedegg, 
the theory of germinal localization 

predentary (predSn'tarl) . [L. prae, 
before ; dens, tooth.] A bone at 
the tip of the jaw of many Dinosaurs 

preepistome (prefip'istom) n. [L.prae, 
before ; Gk. epi, upon ; stoma, 
mouth.] A plate covering the 
basal portion of the epistome of 
certain Arachnids (zool.}. 

prefloration (pre'flora'shun) . [L. 

prae, before ; flos, flower.] The 
arrangement of floral leaves in a 
flower-bud (hot.}. 

prefollation (pre'folia'shun) n. [L. 
prae, before ; folium, leaf.] The 
arrangement of foliage leaves in 
the bud stage (hot. ). 

preformatlon theory, the theory of 
evolution according to which it 
was supposed that each ovum of 
an animal contained a miniature 
adult, and that nourishment only 
was required to develop it into the 
perfect form (dial.). 

prefrontal (prefrun'tal) a. [L. prae, 
before ; frons, forehead.] Appl. a 
bone anterior to the frontal bone 
of certain vertebrates ; appl. paired 
plates or scales anterior to the 
frontal scale in some Reptiles (zool.}. 

preganglionic (pregang'glion'ik) a. 
[L. prae, before ; Gk. gangglion, a 
tumour.] Appl. the (usually) 
medullated fibres from the spinal 
cord to the sympathetic cell station 

preglobultn (preglSb'ulIn) n. [L. 
prae, before ; globulus, a small 
globe.] A compound proteid of 
white blood corpuscles (phys.}. 

prehallux (prehal'uks) n. [L. prae, 
before ; hallex, the great toe?] A 
rudimentary additional digit on the 
hind limb, in some Amphibia and 
Mammals (zool.\ 

prehalteres (prehal'tgrez) n. plu. [L. 
prae, before ; Gk. halter, a weight.] 
The squamae of Diptera (zool.}. 

prehaustorium (pre'hosto'rium) n. [L. 
prae, before ; haurire, to drink.] 
A rudimentary root-like sucker 

prehensile (prehgn'sil) a. [L. pre- 
Jiendere, to seize.] Adapted for 
catching hold, as a suctorial 
tentacle (zool.}. 

prehepatic (pre'he"pat'lk) a. [L. prae, 
before ; hepar, liver.] Appl. that 
part of the digestive tract anterior 
to the liver (emb.\ 

prelacteal (prelak'teal) a. [L. prae, 
before ; lac, milk.] Pert, a denti- 
tion which may occur previous to 
the milk dentition (emb.\ 

prelocallzation (prelo'kaliza'shun) n. 
[L. prae, before ; locus, place.] 
The theory that certain portions of 




the ovum are predestined to develop 
into certain organs or parts (dial.). 

premaxilla (pre'maksil'a) n. [L. 
prize, before ; maxilla, jaw.] A 
paired bone anterior to the maxilla 
in most vertebrates (zool.). 

premaxillary (pre'maksil'ari) a. [L. 
prae, before ; maxilla, jaw.] An- 
terior to the maxillae ; pert, the 
premaxilla (zoo/.). 

premedian (preme'dlan) a. [L. prae, 
before ; medius, middle.] Anterior 
to the middle of a body or part ; 
appl. a vein in front of the median 
vein of certain insect wings (zoo!.). 

premolar (premo'lar) a. [L. prae, 
before ; mola, mill.] Appl. the 
teeth developed between canines 
and molars, the bicuspid teeth 

prenasal (prena'zal) a. [L. prae, 
before ; nasus, nose.] A bone 
developed in the septum in front 
of the mesethmoid in certain 
Mammals (zoo/.). 

preocular (preSk'iilar) a. [L. prae, 
before ; oculus, eye.] In front of 
the eye ; as antennae, scales (zool.). 

preopercle, preoperculum. 

preoperculum (pre'oper'kulum) n. 
[L. prae, before ; operculum, cover.] 
The anterior membrane bone of 
the operculum or gill-cover (zool.). 

preoral (preo'ral) a. [L.prae, before ; 
os, mouth.] Situated in front of 
the mouth ; appl. cilia, etc. (zool.}. 

preorbital (preor'bital) a. [L. prae, 
before ; orbis, circle.] Anterior to 
the orbit ; appl. a membrane bone 
of Teleosts (zool.}. 

prepatagium (prepata'jium) n. [L. 
prae, before ; patagium, border.] 
The alar membrane, or fold of 
skin extending between upper arm 
and forearm of Birds (zool.). 

preplacental (pre'plasgn'tal) a. [L. 
prae, before ; placenta, a flat cake.] 
Occurring before placenta forma- 
tion or development (emb.). 

prepollex (prepol'gks) n. [L. prae, 
before ; pollex, thumb.] A rudi- 
mentary additional digit occurring 
sometimes preaxially to the thumb 
digit of certain Amphibians and 
Mammals (zool.}. 

prepotency (prepo'tgnst) n. [L. prae, 
before ; potens, powerful.] The 

fertilization of a flower by pollen 
from another flower in preference 
to pollen from its own stamens, 
when both are offered simultane- 
ously (dot.) ; capacity of one parent 
to transmit more characteristics to 
the offspring than the other parent 

prepotent (prepo'tent) a. [L. prae, 
before ; potens, powerful.] Trans- 
mitting the majority of character- 
istics (&#/.) ; appl. a flower exhibiting 
a preference for cross-pollination 

prepubis (prepu'bis) n. [L. prae, 
before ; pubes, mature.] Part of 
the pelvic girdle of certain Reptiles, 
anterior to the pubis (zool.). 

prepyramidal (pre'piram'idal) a. [L. 
prae, before ; pyramis, pyramid.] 
In front of the pyramid ; appl. a 
cerebellar fissure (anat.). 

presphenoid (presfe'noid) n. [L. 
prae, before ; Gk. sphen, wedge.] 
In many vertebrates, a cranial bone 
anterior to the basisphenoid (zool.). 

pressor (prgs'or) a. [L. pressare, to 
press.] Appl. nerve-fibres which, 
when stimulated, cause a rise of 
arterial pressure (phys.). 

pressure (presh'iir) n. [L. pressare, 
to press.] Tension in plant tissue 
caused by the turgidity of the cells 

presternal (prester'nal) a. [L. prae, 
before ; sternum, breast - bone.] 
Situated in front of the sternum or 
breast-bone ; pert, the anterior part 
of the sternum (zool.). 

presternum (prester'num) n. [L. 
prae, before ; sternum, breast-bone.] 
The manubrium, or anterior part of 
a sternum (zool.). 

pretrematic (pre'tremat'ik) a. [L. 
prae, before ; Gk. trema, hole.] 
Appl. nerves running in the anterior 
wall of the first gill cleft to the 
pharynx (zool.}. 

prevertebral (preveYtgbral) a. [L. 
prae, before ; -vertebra, a vertebra.] 
Pert, or situated in the region in 
front of the vertebral column ; appl. 
a portion of the base of the skull 
(emb.) \ appl. ganglia of the sympa- 
thetic system (zool.). 

prezygapophysis (prezl'gapofiisTs) n. 
[L. prae, before ; Gk. zygon, yoke ; 




apo, from ; physis, growth.] A 
process on the anterior face of the 
neural arch for articulation with 
the vertebra in front (anat.). 

prickle (prik'l) n. [A.S. prica, a 
point.] A pointed process arising 
through epidermal tissue (bot.). 

prickle cells, cells of the deeper 
layers of stratified squamous 
epithelium : they have short, 
fine, marginal, connecting fibrils 

primary (prl'mari) a. [L. primus, 
first.] First ; principal ; original ; 
appl. axis, feathers, meristem, root, 
wood (biol.). 

primaxil (primak'sil) n. [L. primus, 
first ; axilla, armpit.] The first 
axillary arm of a Crinoid (zool.). 

primibrachs (pri'mibraks) n.plu. [L. 
primus, first ; brachia, arms.] In 
Crinoids, all brachials up to and 
including the first axillary (zool.). 

primine Qpri'min) n. [L. primus, 
first] The external integument 
of an ovule ; occasionally appl. the 
first-formed or internal coat (bot.). 

primite (prim'it) n. [L. primus, first.] 
The first of any pair of individuals 
.of a catenoid colony in the pseudo- 
conjugation of Gregarinida, in 
which the protomerite of one (the 
satellite) becomes attached to the 
deutomerite of another (the primite) 

primitive (prim'itiv) a. [L.primitivus, 
early.] Of earliest origin ; appl. 
groove, knot, streak, aorta, palate, 
ventricle (emb.). 

primordial (prlmdr'dial) a. [L. prim- 
ordium, a beginning.] Primitive ; 
original ; first commenced ; appl. 
ova (emb.), cell, utricle (hot.). 

primordium (primor'dmm) n. [L. 
primordium, a beginning.] Original 
form ; a structure when first in- 
dicating assumption of form ; 
anlage (emb). 

priodont (prfodont) a. [Gk. prion, 
saw ; odous, tooth.] Saw-toothed ; 
appl. stag-beetles with smallest 
development of mandible projec- 
tions (zool.). 

prismatic (prizmat'lk) a. [L. prisma, 
prism.] Like a prism ; appl. leaves 
(bot.) ; consisting of prisms, as the 
prismatic layer of shells (zool.}. 

proamnion (proam'nlon) n. [Gk. 
pro, before ; amnion, a vessel for 
receiving blood.] An area of blasto- 
derm in front of the head of early 
embryos of higher vertebrates 

proangiosperm (proan'jIospSrm) n. 
[Gk. pro, for ; anggeion, vessel ; 
sperma, seed.] A fossil type of 
angiosperm (bot.). 

proatlas (proat'las) n. [Gk. pro, 
before ; Atlas.'] A median bone 
intercalated between atlas and 
skull in certain Reptiles (zool.). 

proboscidiform (pro'bosid'iform) a. 
[Gk. proboskis, trunk ; L. forma, 
shape.] Proboscis-like ; appl. In- 
fusorians with tentacles on a pro- 
boscis-like process (zool.}. 

proboscis (probos'Is) n. \Gk. proboskis, 
trunk.] A trunk-like process of 
the head, as of Insects, Annelids, 
Nemerteans, Elephants (zool.}. 

procambial strand, a longitudinal 
strand of elongated cells near the 
periphery of the plerome of a 
vascular bundle ; a desmogen 
strand (dot.). 

procambium (prokam'blum) n. [L. 
pro, before ; L.L. cambium, nutri- 
ment.] The tissue from which 
vascular bundles are developed 

procarp (pro'karp) . [Gk. pro, for ; 
karpos, fruit.] The female organ 
of red Seaweeds, a one or more 
celled structure containing no differ- 
entiated oosphere (bot.). 

process (pro'sgs) n. [L. pro, forth ; 
cedere, to go.] An outgrowth, pro- 
longation, projection, or eminence 
of any structure. 

processus, a process. 

prochorion (proko'riSn) n. [Gk. pro, 
before ; chorion, skin.] An envelop- 
ing structure of the blastodermic 
vesicle preceding formation of a 
chorion (emb.). 

prochromatin (prokro'matln) n. [Gk. 
Pro, for ; chroma, colour.] Plasmo- 
some substance (cyt.). 

procoelous (prose'lus) a. [Gk. pro, 
before ; koilos, hollow.] With con- 
cave anterior face, as vertebral 
centra (zool.). 

procoracoid (prok6r'akoid) n. [Gk. 
pro, before ; korax, crow.] An 




anteriorly directed process from 
the glenoid fossa of Urodeles (zool.). 

procryptic (prokrlp'tik) a. [Gk. pro, 
for ; kryptos, hidden.] With colora- 
tion adapted for concealment (zoo/.). 

proctal (prok'tal) a. [Gk. proktos, 
anus.] Anal ; appl. fish fins 

proctodaeum (prok'tode'um) n. [Gk. 
proktos, anus ; odos, a way.] The 
latter part of the embryonic ali- 
mentary canal ; formed by anal 
invagination ; a similar ectoderm- 
lined part in certain invertebrates 

procumbent (pr5kum'bent) a. [L. 
pro, forward ; cumbens, lying down.] 
Prostrate ; trailing on the ground ; 
appl. stems (bot.). 

prodentine (proden'tin) n. [L. pro, 
before ; dens, tooth.] A layer of 
uncalcified matrix capping tooth 
cusps before the formation of dentine 

proembryo (progm'brio) n. [Gk. pro, 
for ; embryon, a foetus.] An embry- 
onic structure preceding the true 
embryo ; the first results of spore 
segmentation (hot.). 

progamete (pro'gamet') n. [Gk. pro, 
before ; gamos, union.] A structure 
giving rise to gametes by abstriction, 
in certain Fungi (bot.). 

progamic (progam'ik) a. [Gk. pro, 
before ; gamos, union.] Appl. 
brood-division for gamete produc- 
tion (zool.). 

progeotropism (pro'jeot'ropizm) n. 
[Gk. pro, for ; ge, earth ; trope, a 
turning.] Positive geotropism (&?/.). 

proglottides (prSglot'idez) n. plu. 
[Gk. pro, for ; glotta, tongue.] The 
propagative body-segments of a 
tapeworm, formed by stabilization 
from the neck (zool.) ; sing, pro- 

prognathous (prognath'us) a. [Gk. 
pro, forth ; gnathos, jaw.] Having 
prominent or projecting jaws. 

prohydrotropism (pro'hidrot'ropizm) 
n. [Gk. pro, for ; hydor, water ; 
trope, a turning.] Positive hydro- 
tropism (oof.). 

projectile (prqjeVtil) a. [L. pro, 
forth ; jacere, to throw.] Protrus- 
ible ; that can be thrust forward 

projection (projek'shiin) n. [L. pro, 
forth ; jacere, to throw.] The 
referring of stimulations to end- 
organs of sense by means of the 
connecting projection nerve-fibres 

proleg (pro'leg) n. [L. pro, for ; 
M.E. leg, a leg.] An unjointed 
abdominal appendage of arthropod 
larvae (zool.). 

proliferate (prolif'erat) v. [L. proles, 
offspring ; ferre, to bear.] To re- 
produce repeatedly (biol.). 

proliferation (prolif'era'shun) n. [L. 
proles, offspring ; ferre, to bear.] 
Prolification ; increase by frequent 
and repeated reproduction of any 
kind (biol.). 

proliferous (prolif'erus) a. [L. proles, 
offspring ; ferre, to bear.] Multiply 
ing quickly (biol.) ; appl. bud-bearing 
leaves ; developing supernumerary 
parts abnormally (bot.). 

promitosis (pro'mitd'sis) n. [Gk. pro, 
for ; mitos, thread.] A simple type 
of mitosis exemplified in nuclei of 
protokaryon type (cyt.). 

promontory (prom'ontorl) n. [L. pro, 
forth ; mons, mountain.] A prom- 
inence or projection, as of the 
cochlea (anat.). 

promorphology (pro'morfol'oji) n. 
[Gk. pro, for ; morphe, form ; logos, 
discourse.] Morphology from the 
geometrical standpoint. 

promuscis (promus'is) n. [L. pro- 
muscis, a proboscis.] The proboscis 
of Hemiptera (zoo/.). 

promycelium (pro'mlse'Hum) n. [Gk. 
pro, for ; mykes, mushroom.] The 
mycelium developed from a zygo- 
spore, itself giving rise to a spor- 
angium (bot.),_ 

pronate (pro'nat) a. [L. pronare, to 
bend forward.] Prone ; inclined 

pronation (prona'shun) n. [L. pronare, 
to bend forward.] The act by which 
the palm of the hand is turned 
downwards by means of pronator 
muscles ; cf. supination (phys.). 

pronephric (pronef'rik) a. [Gk. pro, 
before ; nephros, kidney.] Pert, or 
in the region of the pronephros ; 
appl. duct, tubules (emb.). 

pronephros (pronef'ros) n. \, 
before ; nephros, kidney.] The 




head-kidney of embryonic life, 
arising from mesomeric somites, 
functional for a time in lower 
vertebrates, later replaced by meso- 
or meta-nephros (emb.~). 

pronotum (prono'tum) n. [Gk. pro, 
before ; noton, back.] The dorsal 
part of the prothorax of Insects 

pronucleus (pronu'kleus) n. [L. pro, 
before ; nucleus, kernel.] The egg- 
nucleus or sperm-nucleus during 
fertilization (emb.}. 

pronymph (pro'nlmf) n. [L. pro, 
before ; nympha, a maid.] The 
stage in the metamorphosis of 
Diptera preceding the nymph stage 

proostracum (proos'trakum) n. [Gk. 
pro, for ; ostrakon, a testacean 
shell.] The horny pen of a deca- 
pod dibranchiate shell or Belemnite 

prootic (proot'ik) n. \, before ; 
ous, ear.] The anterior bone of the 
otic capsule in vertebrates (zoo/.). 

propagative (prop'aga'tiv) a. [L. 
propagare, to propagate.] Repro- 
ductive ; appl. a cell, a phase, an 
individual of a colony (biol.}. 

propagulum (propag'ulum) n. [L. 
propagare, to propagate.] A bud 
or shoot capable of developing into 
an adult (bot.}. 

propatagium, a prepatagium. 

prophase (prS'faz) n. [Gk. pro, 
before ; phasis, appearance.] The 
preparatory changes, the first stage 
in mitosis (cyt.}. 

prophloem, protophloem. 

prophototropism (pro'fotot'ropizm) n. 
[Gk. pro, for ; phos, light ; trope, a 
turning.] Positive phototropism 

prophyllum (profll'iim) n. [Gk. pro, 
for ; phyllon, leaf.] A small bract 

propleuron (proploor'on) n. [Gk. pro, 
before ; pleura, side.] A lateral 
plate of the prothorax of Insects 

propodeon (propo'deon) n. [Gk. pro, 
before ; pous, foot.] An abdominal 
segment of Hymenoptera in front 
of the petiole or podeon ; otherwise 
the median segment, Latraille's 
segment, etc. (goo/.). 

propodeum, propodeon. 
propodlte (pro'podlt) n. [Gk. pro, 
before ; pous, foot.] In Malacos- 
traca, the segment of a foot sixth 
from the body (zoo/.). 
propodium (propo'dlum) n. [Gk. pro, 
before ; pous, foot.] The small 
anterior part of a Molluscan foot 

propteryglum (pro'tSrij'ium, prop'- 
tgrij'ium) n. [Gk. pro, before ; 
pterygion, a little wing.] The fore- 
most of three basals supporting the 
pectoral finof Elasmobranchs (zoo/.). 
propulsive pseudopodium, in some 
Neosporidia, a pseudopodium de- 
veloped posteriorly which by its 
elongation pushes the body forward 

propupa (propu'pa) n. [, before ; 
pupa, a puppet.] A stage in insect 
metamorphosis preceding the pupa 
stage (zoo/.). 

propygidium (pro'prjld'ium) n. [Gk. 
pro, before ; pyge, the rump.] The 
dorsal plate anterior to the pygidium 
in Coleoptera (zoo/.). 
prorachls (prorak'Ts) n. [Gk. pro, 
before ; rhachis, spine.] The face 
of Pennatulacea which is sterile and 
coincides with the asulcar aspect of 
the terminal zooid (zoo/.). 
proscapula (proskap'ula) n. [L. pro, 
before ; scapula, shoulder - blade.] 
The clavicle (zoo/.). 
proscolex (prosko'le'ks) n. [Gk. pro, 
before ; skolex, worm.] A rounded 
cyst with fluid-filled cavity, a stage 
in the development of the Tape- 
worm (zoo/.). 

prosecretin (pro'sekre'tTn) n. \, 
before ; secretus, separated.] The 
precursor of secretin (phys.\ 
prosencephalon (pr6s'6nkgf'alon, -sef-) 
n. [Gk. pro, before ; engkephalon, 
brain.] The telencephalon, or fore- 
brain (anat.). 

prosenchyma (prose'ng'kima) n. [Gk. 
pros, near ; engchyma, infusion.] 
Tissue of prosenchymatous cells, 
prosenchymatous (pros'gngkim'atus) 
a. [Gk. pros, near ; engchyma, 
infusion.] Appl. elongated pointed 
cells, with thin or thick cell-walls, 
in plant tissue (bot.}. 
prosethmoid (prosgth'moid) . [Gk. 
Pros, near ; ethinos, sieve.] An 




anterior cranial bone of Teleosts 

prosiphon (prosi'fon) n. [Gk. pro, 
for ; siphon, tube.] A spout-like 
prolongation of the edges of the 
mantle - flaps of certain Molluscs 

prosocoel (pros'osel) n. [Gk. pros, 
near ; koilos, hollow.] A narrow 
cavity in the epistome of Mollus- 
coidea, the first main part of the 
coelom (zool.}. 

prosodetic (pros'odSt'Tk) a. [Gk. 
prosodos, advance.] Anterior to 
the beak ; appl. certain bivalve 
ligaments (zool.}. 

prosodus (pros'odus) n. [Gk. prosodos, 
advance.] A delicate canalicule 
between chamber and incurrent 
canal in some Sponges (zool.}. 

prosoma (proso'ma) n. [Gk. pro, 
before ; soma, body.] The anterior 
part of the body ; a cephalothorax 

prosopyle (pros'opil) n. [Gk. proso, 
forward ; pyle, gate.] The aperture 
of communication between adjacent 
incurrent and flagellate canals in 
some Sponges (zool.}. 

prostalia (prosta'lia) n. plu. [L. pro, 
forth ; stare, to stand.] Projecting 
spicules of Hexactinellids (zool.}. 

prostate (pros'tat) a. [, before ; 
stare, to stand.] Appl, a gland 
placed around the commencement 
of the male urethra in the pelvic 
cavity (anat.}. 

prostatic (prostat'Ik) a. [L. pro, 
before ; stare, to stand.] Pert, the 
prostate gland ; appl. duct, nerve, 
sinus, utricle (anat.}. 

prostemmate (prdste'm'at) a. [Gk. 
pro, before ; stemma, wreath.] 
Appl. an ante-ocular structure or 
organ of some Collembola, of 
doubtful function (zool.}. 

prostemmatic, prostemmate. 

prosternum (prosteYnum) n. [L. 
pro, before ; sternum, breast-bone.] 
The ventral part of the prothorax 
of Insects (zool.}. 

prosthion (pros'thion) n. [Gk. pros- 
thios, foremost.] The alveolar 
point ; the middle point of the 
upper alveolar arch (anat.}. 

prostomiate (prosto'miat) a. [Gk. 
pro, before ; stonia, mouth.] Having 

a portion of the head in front of the 
mouth (zool.}. 

prostomium (prosto'mium) n. [Gk. 
pro, before ; stoma, mouth.] In 
Worms and Molluscs, the part of the 
head anterior to the mouth (zool.}. 

prostrate (pros'trat) a. [L. prostratus, 
thrown down.] Procumbent ; trail- 
ing on the ground (hot.). 

protandrism (protan'drizm) n. [Gk. 
protos, first ; andros, male.] Pro- 
tandry ; sometimes exclusively in 
zoological application (biol.}. 

protandrous (protan'drus) a. [Gk. 
protos, first ; andros, male.] Ex- 
hibiting protandry (biol.}. 

protandry (protan'dri) n. [Gk. protos, 
first ; andros, male.] Condition of 
hermaphrodite plants and animals 
where the male elements mature 
and are shed before the female 
elements mature (biol.}. 

protegulum (proteg'ulum) n. [L. pro, 
before ; tegulum, a covering.] The' 
semicircular or semielliptical em- 
bryonic shell of Brachiopods (zool.}. 

proteid (pro'teid) n. [Gk. protos, 
first ; eidos, resemblance.] The 
nitrogenous material of plant cells ; 
albuminous substance ; a term 
subject to varying restrictions in 
different authors (phys.}. 

protein (pro'tein) n. [Gk. protos, first.] 
Albuminous substance ; a nitro- 
genous compound of cell proto- 
plasm ; the sum-total of nitrogen 
present in protoplasm ; a term of 
variable application (phys.}. 

proteolytic (pro'teollt'lk) a. [Gk. 
protos, first ; lysis, a loosing.] 
Appl. ferments which change pro- 
teins into proteoses and peptones, 
as pepsin, trypsin (pkys.}. 

proteose (pro'teos) n. [Gk. protos, 
first.] The first cleavage product 
of the action of hydrolysis on a 
protein molecule (phys.}. 

proterandric (pro'teran'drik) a. [Gk. 
proteros, earlier ; andros, male.] 
Appl. hermaphroditism in which 
ovaries and testes are functional 
at different times (biol.}. 

proterandrous, protandrous. 

proteranthous (pro'teran'thus) a. 
\G\s..proteros,c.a.r\iei:; anthos, flower.] 
Flowering before foliage leaves 
appear (bot.}. 




proteroglyph (pro'tgrogHf) a. [Gk. 

proteros, earlier ; glyfihein, to carve.] 

I Having the specialized fang teeth 

permanently erect ; opp. soleno- 

- glyph (zool.}. 

proterogyny, protogyny. 

prothallium, prothallus. 

prothalloid (prothal'oid) a, [Gk. pro, 
before ; thallos, young shoot ; eidos, 
form.] Like a prothallium (hot.}. 

prothallus (prothal'us) n. [, 
before ; thallos, young shoot.] A 
small, thin, fleshy mass developed 
from spores of ferns, itself produc- 
ing antheridia and archegonia (dot.}. 

protheca (prothe'ka) n. [Gk. pro, 
before ; theke, a box.] The rudi- 
ment of coral formation ; the basal 
part of the coral calicle (zool.}. 

prothorax (protho'raks) n. [Gk. pro, 
before ; thorax, breast.] The an- 
terior thoracic segment of Arthro- 
pods (zool.}. 

prothrombin (prothrom'bln) n. [Gk. 
pro, before ; thrombos, clot.] Throm- 
bogen (phys.}. 

prothyalosome (prothfalosom) n. 
[Gk. pro, before ; hyalos, glass ; 
soma, body.] The area surrounding 
the germinal spot in the germinal 
vesicle (emb.}. 

protista (protts'ta) n. plu. [Gk. pro- 
tistos, first of all.] The assemblage 
of simple and primitive living beings 
from which animals and plants 
arise (owl.}. 

protobasidium (pro'tobasid'Ium) n. 
[Gk. protos, first ; basidion, a small 
pedestal.] A basidium producing 
a mycelium of four cells from each 
of which a sporidium is developed 
by abstriction (bot.}. 

protoblast (pro'toblast) n. [Gk.protos, 
first ; blastos, bud.] A naked cell, 
devoid of membrane ; the first or 
single-cell stage of an embryo ; the 
internal-bud stage in the life-history 
of Neosporidia (zool.}. 

protocercal (pro'toseVkal) a. [Gk. 
protos, first ; kerkos, tail.] Having 
the caudal fin divided into two ecjual 
lobes ; diphycercal, the primitive 
form of caudal fin (zool.}. 

protocerebrum (pro'toseVgbrum) . 
[Gk. protos, first ; L. cerebrum, 
brain.] The anterior pair of gangli- 
onic centres of Crustacea (xool.}. 

protocnemes (pro'toknemz) n. plu. 
[Gk. protos, first ; knetne, a wheel- 
spoke.] The six primary pairs of 

larval shell of Molluscs, indicated 
by the cicatrix on the adult shell 

protocone (pro'tokon) n. [Gk. protos, 
first ; konos, cone.] The inner cusp 
of an upper jaw molar (anat.}. 

protoconid (pro'toko'nld) n. [Gk. 
protos, first ; konos, cone ; eidos, 
form.] The external cusp of a 
lower jaw molar (anat.}. 

protoconule (prd'toko'nul) n. [Gk. 
protos, first ; konos, cone.] An an- 
terior intermediate cusp of an upper 
jaw molar (anat.}. 

protocranium (pro'tokra'nlum) n. 
[Gk. protos, first ; kranion, skull.] 
A name sometimes given to the 
posterior part of the epicranium of 
Insects (zool.}. 

protoepiphyte (pro'togp'iflt) n. [Gk. 
Protos, first ; epi, upon ; phyton, 
plant.] A plant growing upon 
another and getting all its nourish- 
ment from that other (bot.}. 

protogenic (pr6'tqjgn'ik)a. [Gk.. protos, 
first ; genos, offspring.] Persistent 
from the beginning of development 
onwards (biol.}. 

protoarynous (protSj'inus) a. [Gk. 
protos, first ; gyne, woman.] Hav- 
ing female elements mature before 
male (biol.}. 

protogyny (prot8j'mi) n. [Gk. protos, 
first ; gyne, woman.] Condition of 
hermaphrodite plants and animals 
in which female elements mature 
and are spent before maturation of 
male elements (biol.}. 

protokaryon (pro'tokar'lon) n. [Gk. 
protos, first ; karyon, nut.] A simple 
or primitive nucleus consisting of 
a mass of chromatin suspended in 
nuclear sap, as in small limax 
Amoebae (cyt.}. 

protoloph (pro'toldf) n. [Gk. protos 
first ; lophos, crest.] The anterior 
transverse crest of upper jaw molars 

protomala (pro'tb'ma'la) n. [Gk. 
protos, first ; L. mala, cheek.] A 
myriapod mandible (zool.}. 




protomerite (pr6t6m'6rit) n. [Gk. 
protos, first ; meros, part.] The an- 
terior part of the medullary proto- 
plasm of adult Gregarines ; cf. 
deutomerite (zool.}. 

protomonostelic (pro'to mon'ostel'ik) 
a. \Gk. protos, first ; monos, alone ; 
stele, column.] Appl. a stem or 
root with a protostele or central 
cylinder (bot.}. 

protonema (pro'tone'ma) n. [Gk. 
protos, first ; nema, thread.] The 
germination structure of Mosses, 
from which the moss plant buds 

protonematoid (pro'tonem atoid) a. 
[Gk. protos, first ; nema, thread ; 
eidos, form.] Like a protonema 

protonephridial (pro'tonefrid'ial) a. 
[Gk. protos, first ; nephros, kidney.] 
Appl. the excretory water-vascular 
system of Flat-worms (zool.}. 

protopepsia (pro'to pep'sia) n. [Gk. 
protos, first ; pepsis, a digesting.] 
Solution and alteration of food- 
material accomplished in the di- 
gestive tract (phys.}. 

protophloem (pro'toflo'em) n. [Gk. 
protos, first ; phloios, tree-bark.] 
The first phloem elements of a 
vascular bundle (dot."). 

protophyte (pro'tofit) n. [Gk. protos, 
first ; phyton, plant.] A unicellular 
vegetable organism or primitive 
plant (bot.}. 

protoplasm (pro'toplazm) n. [Gk. 
protos, first ; plasma, form.] Cell 
substance ; cytoplasm and karyo- 
plasm (cyt.}. 

protoplasmic (pro'toplaz'mik) a. [Gk. 
protos, first ; plasma, form.] Pert. 
or consisting of protoplasm (biol.}. 

protoplast (pro'toplast) n. \Gk.protos, 
first ; plastos, formed.] An energid ; 
a living uninucleate primitive pro- 
toplasmic unit (biol.}. 

protopodite (protop'odit) n. [Gk. 
protos, first ; pous, foot.] The 
basal segment of a typical crus- 
tacean limb (zool.}. 

protospore (pro'tospor) n. [Gk. protos, 
first ; sporos, seed.] A spore of 
the first generation ; a mycelium- 
producing spore (hot.}. 

protostele (pro'tostel) n. [Gk. protos, 
first ; stele, column.] The concentric 

bundle or central cylinder of vascu- 
lar tissue of most roots and some 
stems (hot.}. 

prototheca (pro'tothe'ka) n. [Gk. 
protos, first ; theke, box.] A skeletal 
cup-shaped plate at the aboral end 
of a coral embryo, the first skeletal 
formation (zool.}. 

prototroch (pro'totrok) n. [Gk. protos, 
first ; trochos, wheel.] A pre-oral 
circlet of cilia of a trochosphere or 
trochelminth larva (zool.}. 

prototrophic (pro'totrof'ik) a. [Gk. 
protos, first ; trophe, nourishment.] 
Nourished from one supply or in 
one manner only : appl. bacteria 

prototype (pro'totip) n. [Gk. protos, 
first ; typos, model] An original 
type species or example ; an an- 
cestral form (biol.}. 

protovertebrae (pro'to veVtSbre) n. plu. 
[Gk. protos, first ; L. vertebra, a 
vertebra.] A series of primitive 
segments in a vertebrate embryo, 
once thought to be the beginnings 
of vertebrae (emb.}. 

protoxylem (pro'tb'zl'lem) n. [Gk. 
protos, first ; xylon, wood.] Primary 
xylem lying next the pith of stems 

protozoaea (pro'tozo'ea) n. [Gk. protos, 
first ; zoon, animal.] A stage in 
the life-history of certain Arthropods 
succeeding the free -swimming 
nauplius (zool.}. 

protozoology (pro'tozool'ojl) n. [Gk. 
protos, first ; zoon, animal ; logos, 
discourse.] The department of 
Zoology dealing with the simplest 
animal organisms. 

protozoon (pro'tozo'on) n. [Gk.protos, 
first ; zoon, animal.] A unicellular 
animal organism (zool.}. 

protractor (protrak'tor) n. [L. pro, 
forth ; tractus, drawn out.] A 
muscle which draws out or extends 
a part (anat.}. 

protriaene (pro'trlen) n. [Gk. pro, 
before ; triaina, trident.] A triaene 
with anteriorly-directed branches 

proventriculus (pro'ventrik'ulus) n. 
[L. pro, before ; ventriculus, a small 
stomach.] In Insects, the digestive 
chamber anterior to the stomach ; 
in Worms, that anterior to the 




gizzard ; in Birds, the glandular 
stomach anterior to the gizzard 

provinculum (proving'kulum) n. [L. 
pro, before ; vinculum, a chain.] 
A primitive hinge of young stages 
of certain Lamellibranchia (zool.). 

proximal (prok'simal) a. [L. proxi- 
mus, next.] Nearest the body or 
centre ; opp. distal (biol.). 

pruinose (proo'inos) a. [L. pruina, 
hoar-frost.] Covered with whitish 
particles or globules ; covered by 
bloom (bot.). 

psalterium (solte'rium, sal-) n. [L. 
psalterium, a psalter.] The third 
stomach of Ruminants, the omasus, 
or manyplies (zool.) ; the lyra, a 
thin triangular lamina joining 
lateral portions of the fornix 

psammophilous (samof'ilus, psam-) a. 
\G\a.psammos, sand \philos, loving.] 
Thriving in sandy places (dot.). 

psamxnophyte (sam'oflt, psam-) n. 
{Gk.. psammos, sand ;phyton, plant.] 
A plant growing in dry, sandy 
ground (oof."). 

pseudambulacrum (su'dambula'krum, 
psu-) n. [Gk. pseudes, false ; L. 
ambulare, to walk.] A term for 
the lancet-plate, with adhering side- 
plates and covering plates of Blast- 
oidea (zool.). 

pseudannual (sudan'ual, psu-) n. [Gk. 
pseudes, false ; L. annus, year.] A 
plant which completes its growth 
in one year but provides a bulb or 
other means of surviving winter 

pseudaposematic (sudap'6s6mat'ik, 
psu-) a. [Gk. pseudes, false ; apo, 
from ; sema, sign.] Imitating the 
warning coloration or other pro- 
tective features of hurtful animals 

pseudaxis (sudak'sis, psu-) n. [Gk. 
pseudes, false ; axis, axle.] An 
apparent main axis (bot.). 

pseudhaemal (sudhe'mal, psu-) a. 
[Gk. pseudes, false ; Jiaima, blood.] 
Appl. the vascular system of cer- 
tain Worms and Echinoderms 

pseudholoptic (su'dholop'tik, psu-) a. 
[Gk. pseudes, false ; holes, whole ; 
optikos, relating to sight.] Inter- 

mediate between holoptic and 
dichoptic, conditions in the eyes 
of Diptera (zool.). 

pseudimago (su'dima'go, psu-) n. [Gk. 
pseudes, false ; L. imago, image.] 
A stage between pupa and imago 
in the metamorphosis of certain 
Insects (zool.). 

pseudoalveolar (su'doalve'olar, psu-) 
a. [Gk. pseudes, false ; L. al-vetts, 
a hollow.] Appl. a structure of 
cytoplasm containing starch grains 
or deutoplasm spheres (cyt.). 

pseudoaquatic (su'doakwat'lk, -kwot-, 
psu-) a. [Gk. pseudes, false ; L. 
aqua, water.] Thriving in moist 
ground (bot.). 

pseudobrachium (sii'dobra'kmm, psu-) 
n. [Gk. pseudes, false ; brachion, 
arm.] The kind of arm formed 
from elongated pterygials of the 
pectoral fin of Pediculates (zool.). 

pseud obranchia (su'dobrang'kla, psu-) 
n. [Gk. pseudes, false ; brangchia, 
gills.] An accessory gill of some 
Fishes, not respiratory in function 

pseudobulb (su'dobulb, psu-) n. [Gk. 
pseudes, false ; L. bulbus, bulb.] A 
thickened internode of Orchids for 
storage of water and reserves (bot.). 

pseudobulbll (su'dobul'bil, psu-) n. 
[Gk. pseudes, false ; L. bulbus, bulb.] 
An outgrowth of some Ferns, a 
substitute for sporangia (bot.). 

pseudobulbous (su'dobul'biis, psu-) a. 
[Gk. pseudes, false ; L. bulbus, bulb.] 
Adapted to xerophytic conditions 
through development of pseudo- 
bulbs (bot.). 

pseudocarp (su'dokarp, psu-) n. [Gk. 
pseudes, false ; karpos, fruit.] A 
false fruit, or one in which other 
parts than the ovary assist in 
formation (bot.). 

pseudocentrous (su'dosfin'triis, psu-) a. 
[Gk. pseudes, false ; L. centrum, 
centre.] Appl. vertebrae composed 
of two pairs of arcualia meeting and 
forming a suture laterally (Pal.). 

pseudochromatln, prochromatin 

pseudoconch (su'd6k8ngk, psu-) n. 
[Gk. pseudes, false ; kongche, shell.] 
A structure developed above and 
behind the true concha in Crocodiles 




pseudocoue (su'dokon, psu-) n. [Gk. 
pseudes, false ; konos, cone.] A 
soft gelatinous cone occurring in 
numbers in some insect eyes 

pseudoconjugation (su'dokonj ooga'- 
shun, psu-) n. [Gk. pseudes, false ; 
L. cum, with ; jugum, yoke.] Con- 
jugation of Sporozoa in which two 
individuals, temporarily and without 
true fusion, join end to end, proto- 
merite to deutomerite, or side to 
side (sool.). 

pseudocostate (su'dokos'tat, psu-) a. 
[Gk. pseudes, false ; L. costa, rib.] 
False-veined ; having a marginal 
vein uniting all others (bot.). 

pseudocyst (su'dosist, psu-) n. [Gk. 
pseudes, false ; kystis, bladder.] A 
residual protoplasmic mass which 
swells and ruptures, liberating spores 
of Sporozoa (zool.). 

pseudodeltidium (su'dodeltid'ium, 
psu-) n. [Gk. pseudes, false ; delta, 
D.] A plate partly or entirely 
closing the deltidial fissure in the 
ventral valve of certain Testi- 
cardines (zool.). 

pseudoderm (su'doderm, psu-) n. [Gk. 
pseudes, false ; derma, skin.] A 
kind of covering or skin of certain 
compact sponges, formed also 
towards the pseudogastric cavity 

pseudodont (su'dodont, psu-) a. [Gk. 
pseudes, false ; odous, tooth.] Hav- 
ing false or horny teeth, as Mono- 
tremes (zool.). 

pseudofoliaceous (su'dofolla'shus, 
psu-) a. [Gk. pseudes, false ; L. 
folium, leaf.] With expansions 
resembling leaves (bot.). 

pseudogaster (su'dogas'tgr, psu-) n. 
[Gk. pseudes, false ; gaster, stomach.] 
An apparent gastral cavity of 
certain Sponges, opening to the 
exterior by a pseudoosculum and 
having the true oscula opening into 
itself (zool.). 

pseudogastrula (su'dogas'troola, psu-) 
n. [Gk. pseudes, false ; gaster, 
stomach.] The stage of Sycon 
development when the archaeocytes 
become completely enclosed by the 
flagellate cells (zool.). 

pseudoheart, the axial organ of 
Echinoderms (zool.). 

psu-) n. [Gk. pseudes, false ; L. 
manubrium, handle.] The manu- 
brium considered as a process of 
the subumbrella where the former 
contains the gastric cavity in 
certain Trachylinae (zool.). 

pseudometamerism (su'dometam'- 
erlzm, psu-) n. [Gk. pseudes, false ; 
meta, between ; meros, part.] Ap- 
parent serial segmentation ; an 
approximation to metamerism, as in 
certain Flat-worms (zool.). 

okotile'db'nus, psu-) a. [Gk. pseudes, 
false ; monos, alone ; kotyledon, a 
cup-like hollow.] With two coty- 
ledons coalescing to appear as one 

pseudomonocyclic (su'domon'b'sik'lik, 
psu-) a. \Gk.pseudes, false ; monos, 
alone ; kyklos, circle.] Appl. Crin- 
oids with infrabasals absent in 
adults but present in the young or 
in near ancestors (zool.\ 

pseudonavicella (su'donavisel'a, psu-) 
n. [Gk. pseudes, false : L. namcella, 
small boat.] A small boat-shaped 
spore containing sporozoites, in 
Sporozoa (zool.). 

pseudonuclein, paranuclein (cyt.). 

pseudonucleoli (su'donukle'olT, psu-) 
n. plu. [Gk. pseudes, false ; L. 
nucleus, kernel.] Knots or granules 
in nuclear reticulum not true nucleoli 

pseudonychium (su'donik'ium, psu-) 
n. [Gk. pseudes, false ; onyx, claw.] 
A lobe or process between claws 
of Insects (zool.). 

pseudoosculum (su'doos'kulum, psu-) 
n. [Gk. pseudes, false ; L. osculum, 
small mouth.] The exterior opening 
of a pseudogaster (zool.). 

pseudoparenchyma (su'dopareng'- 
kima, psu-) n. [Gk. pseudes, false ; 
para, beside ; engchyma, infusion.] 
A tissue-like collection of hyphae 
resembling parenchyma (bot.). 

pseudoperculum (su'doper'kulum, 
psu-) n. [Gk. pseudes, false ; L. oper- 
culum, lid.] A structure resembling 
an operculum or closing membrane 

pseudoperlanth (su'do'peVianth, psu-) 
n. [Gk. pseudes, false ; peri, round ; 
anthos, flower.] An archegonium- 




investing envelope of certain Liver- 
worts (bot.). 

pseudoperidium (su'dope'rld'ium, psu-) 
n. [Gk. pseudes, false ; peridion, 
small wallet.] The aeciospore en- 
velope of certain Fungi (hot.). 

pseudoplasmodium (su'ddplazmo'- 
dlum, psu-) n. [Gk. pseudes, false ; 
plasma, form.] An aggregation of 
amoebulae without fusion of their 
protoplasmic bodies (zool}. 

pseudopodiospore (sudopo'diospor, 
psu-) n. [Gk. pseudes, false ; pous, 
foot ; sporos, seed.] An amoebula 
or amoeboid swarm-spore which 
moves by means of pseudopodia 

pseudopodium (su'dopS'dlum, psu-) n. 
[Gk. pseudes, false ; pous, foot.] A 
blunt protrusion of ectoplasm serv- 
ing for locomotion and prehension 
in Protozoa (zool.) ; in certain 
Mosses, the sporogonium-supporting 
pedicel (bot.). 

pseudopore (su'dopor, psu-) n. [Gk. 
pseudes, false ; poros, channel.] A 
small orifice between outermost 
tube and intercanal system of cer- 
tain Sponges (zool.). 

pseudopupa (su'dopu'pS, psu-) n. [Gk. 
pseudes, false ; L. pupa, puppet.] 
The semi-pupa or coarctate stage 
of certain insect larvae (zool.). 

pseudoramose (su'dora'mos, psu-) a. 
[Gk. pseudes, false ; L. ramus, 
branch.] Having false branches 

pseudoramulus (su'dor&m'ulus, psu-) n. 
[Gk. pseudes, false ; L. ramulus, 
small branch.] A spurious branch 
of certain Algae (bot.}. 

pseudo-reduction, the preliminary 
division of chromatin-rods preced- 
ing the formation of tetrads and 
the actual reduction in maturation 

pseudorhabdltes (su'dor&b'dlts, psu-) 
n.plu. [Gk. pseudes, false ; rhabdos, 
rod.] Granular masses of formed 
secretion produced by gland-cells 
of Rhabdocoelida (zool.). 

pseudoscolex (su'dosk5'16ks, psu-) n. 
[Gk. pseudss, false ; skolex, worm.] 
Modified anterior proglottides of 
certain Cestoids where the true 
scolex is absent (zool.). 
pseudoseptate (su'dosSp'tat, psu-) a. 

S3k. pseudes, false ; L. septum, 
ivision.] Apparently, but not 
morphologically, septate (bot.).' 

pseudosessile (su'dosSs'il, psu-) a. 
[Gk. pseudes, false ; L. sedere, to sit.] 
Appl. the abdomen of petiolate 
Insects when the petiole is so short 
that the abdomen is close to the 
thorax ; cf. pedicellate (zool.). 

pseudosperm (su'ddspgrm, psu-) n. 
[Gk. pseudes, false ; sperma, seed.] 
A false seed or carpel (bot.). 

pseudospore (su'dospor, psu-) n. [Gk. 
pseudes, false ; sporos, seed.] A 
teliospore or winter-spore of certain 
Rusts (bot.). 

pseudostoma (su'dosto'ma, psu-) n. 
[Gk. pseudes, false ; stoma, mouth.] 
A temporary mouth ; a mouth-like 
opening ; a pseudoosculum (zool.). 

pseudovarium (su'dova'rlum, psu-) n. 
[Gk. pseudes^ false ; L. ovarium, 
ovary.] An ovary producing pseu- 
dova (zool.). 

pseudovitellus (su'ddvttgl'us, psu-) n. 
[Gk. Pseudes) false ; L. -vitellus, egg- 
yolk.] A cellular double-string 
structure of Aphidae, a supposed 
substitute for absent Malpighian 
tubes (zool.). 

pseudovum (sudo'vum, psu-) n. [Gk. 
pseudes, false ; L. ovum, egg.] An 
ovum that can develop without 
fertilization ; a parthenogenetic 
ovum ; the earlier condition of the 
viviparously - produced Aphidae 

pseudozoaea (su'dozo'eS, psu-) n. [Gk. 
pseudes, false ; zoon, animal.] A 
larval stage of Stomatopods, so- 
called from its resemblance to the 
zoaea stage of Decapods (zool.). 

psoas (so'as, pso-) n. [Gk. psoa, 
loins.] Name of two loin muscles 

psorosperms (so'rpspSrmz, pso-) n. 
plu. \Gk.psora, itch ; sperma, seed.] , 
Sporozoa ; parasitic organisms 
generally (biol.). 

pteridology (teYldSl'bjf, pteY-) n. [Gk. 
pteris, fern ; logos, discourse.] The 
branch of Botany dealing with ferns. 

pteridophyte (teYldoflt, pt6r-) n. 
[Gk. pteris, fern ; phyton, plant.] 
A plant of the fern group (bot.). 

pterion (teVl6n, ptfir-) n. [Gk. pteron, 
wing.] The point of junction of. 



parietal, frontal, and great wing of 

sphenoid (anat.). 
pterocarpous (ter'okar'pus, pter-) a. 

[Gk. pteron, wing ; karpos, fruit.] 

With winged fruit (bot.}. 
pteroid (ter'oid, pter-) a. [Gk. pteris, 

fern ; eidos, resemblance.] Like a 

fern (bot.}. 
pteropaedes (teYope'dez, pt6r-) n. plu. 

[Gk. pteron, wing ; pats, child.] 

Birds able to fly when newly 

hatched (sool.). 
pteropegum (teYope'gum, pter-) n. 

[Gk. pteron, wing ; pegos, firm.] 

An insect's wing socket (zool.). 
pteropodium (teYopo'dium, pt6r-) n. 

[Gk. pteron, wing ; pous, foot.] A 

winged foot, as of certain bats (zool.). 
pterospermous (ter'osper'mus, pter-) 

a. [Gk. pteron, wing ; sperma, 

seed.] With winged seeds (bot.}. 
pterostigma (ter'ostig'ma, ptSr-) n. 

[Gk. pteron, wing ; stigma, mark.] 

An opaque cell on certain insect 

wings (zool.). 

pterotheca (teYothe'ka, pt6r-) n. [Gk. 
pteron, wing ; theke, a case.] The 

wing-case of pupae (zool.). 
pterotic (tfirot'ik, pter-) n. \Gk.pteron, 

wing ; ous, ear.] A cranial bone 

overlying the horizontal semicircular 

canal of the ear (zool.). 
pterygial (terij'ial, pt6r-) a. [Gk. 
pteryx, wing.] Pert, a wing or fin ; 
appl. a bone supporting a fin-ray 
pterygiophore (tSrij'ipfor, ptSr-) n. 

gik. pteryx, wing ; pherein, to bear.] 
ne of a row of cartilaginous rays 
forming the skeleton of median 
fins (zool.}. 

pterygium (terlj'ium, pt6r-) n. [Gk. 
pteryx, wing.] A prothoracic pro- 
cess of weevils ; a vertebrate limb 

pterygobranchiate (teVigdbrang'kiat, 
pter-) a. [Gk. pteryx, wing ; 
brangchia, gills.] Having spread- 
ing or feathery gills, as certain 
Crustaceans (zool.). 

pterygoda (teYfgp'da, ptfir-) n. plu. 
[Gk. pteryx, wing ; eidos, resem- 
blance.] The tegulae of an Insect 

pterygoid (tgr'igoid, ptSr-) n. [Gk. 
pteryx, wing ; eidos, form.] A 
cranial bone (zool.) ; a. wing-like ; 

appl. the wing-like processes of the 
sphenoid, also canal, fissure, fossa, 
plexus, muscles (anat.). 

pterygomandibular (ter'igomandib'- 
ular, pter-) a. [Gk. pteryx, wing ; 
L. mandibulum, jaw.] Pert, ptery- 
goid and mandible ; appl. a 
tendinous band of the buccopharyn- 
geal muscle (anat.). 

pterygomaxillary (ter'igomaksirari, 
pter-) a. [Gk. pteryx, wing ; L. 
maxilla, jaw.] Appl. a fissure 
formed by divergence of the maxilla 
from the pterygoid process of the 
sphenoid (anat.). 

pterygopalatal, pterygopalatine. 

pterygopalatine (ter'igb'pal'atin, pter-) 
a. [Gk. pteryx, wing ; L. palatus, 
palate.] Pert, the region of ptery- 
goid and palatal cranial bones ; 
appl. canal, fossa, groove (anat.). 

pterygoquadrate (ter'igokwod'rat, 
ptgr-) a. [Gk. pteryx, wing ; L. 
quadratus, squared.] Appl. a carti- 
lage constituting the dorsal half of 
the mandibular arch of certain 
Fishes (zool.). 

pterygospinous (tSr'igospl'nus, pter-) 
a. [Gk. pteryx, wing ; L. spina, 
spine.] Appl. a ligament stretching 
from lateral pterygoid plate to 
spinous process of sphenoid (anat.). 

Pterylae (ter'ile, pter-) n. plu. [Gk. 
pteron, feather ; yle, a wood.] The 
feather tracts of a bird's body, or 
the areas on which feathers spring, 
as distinguished from the un- 
feathered areas or apteria (zool.). 

pterylosis (terilo'sis, ptgr-) n. [Gk. 
pteron, feather ; yle, a wood.] Ar- 
rangement of pterylae and apteria 
in Birds (zool.). 

ptilinum (tili'num,.ptil-). [Gk.ptilon, 
feather.] A head- vesicle or bladder- 
like expansion of the head of a 
fly emerging from the pupa, useful 
for rupturing the hard covering, 
introverted when the insect is 
mature ; found in about one-half of 
the Diptera (zool.). 

ptyalin (tl'alin, ptl-) n. [Gk. ptyalon, 
saliva.] A digestive ferment of 
saliva (phys.). 

ptyxis (tik'sis, ptik-) n. [Gk. ptyxis, 
a folding.] The form in which 
young leaves are folded or rolled 
on themselves in the bud (bot.). 




puberty (pu'beYtif) n. [L. pubertas, 
adult state.] Sexual maturity (phys.). 

puberulent (puber'ul6nt) a. [L. pubes, 
adult.] Covered with down or 
fine hair (dot.). 

pubes (pu'bez) n. [L. pubes, adult.] 
The pubic region (anat.). 

pubescence (pu'be's'e'ns) n. [L. pu- 
bescere, to become mature.] Downy 
or hairy covering on some plants 
and certain insects (biol.). 

pubescent (pube's'e'nt) a. [L. pubescere, 
to become mature.] Covered with 
soft hair or down (dot.'). 

pubic (pu'blk) a. [L. pubes, mature.] 
In the region of the pubes ; appl. 
arch, ligament, tubercle, vein 
(a nat.). 

pubis (pu'bls) n. [L. pubes, mature.] 
The anterior part of the hip-bone, 
consisting of body and ramus 
(anat.) ; the antero-ventral portion 
of the pelvic girdle (zool.). 

pudendal (pudSn'dal) a. [L. pudere, 
to be ashamed.] In the region of 
the pudendum ; appl. artery, cleft, 
nerve, veins (anat.). 

pudendum (pudSn'dum) n. {L.pudere, 
to be ashamed.] The vulva, or 
externals of the female organs of 
generation (anat.). 

pudic, pudendal. 

pullulation (pul'ula'shun) n. [L. 
pullulare, to sprout.] Gemmation ; 
reproduction by vegetative budding, 
as in yeast cells (oof.). 

pulmobranchia (puTmobrang'kia) n. 
[L. pulmo, lung ; Gk. brangchia, 
gills.] A gill-like organ adapted to 
air-breathing conditions ; a lung 
book, as of Spiders (zool.}. 

pulmogastric (pul'mogas'trik) a. [L. 
pulmo, lung ; gaster, stomach.] 
Pert, lungs and stomach (anat.}. 

pulmonary (pul'monari) a. {L. pulmo, 
lung.] Pert, lungs ; appl. artery, 
ligament, valves, veins, pleura 

pulmonary cavity or sac, the mantle- 
cavity of Molluscs without ctenidia : 
it functions as a lung (zool.}. 

pulmones (pulmo'nez) n. plu. [L. 
pulmo, lung.] Lungs (anat.}. 

pulp (pulp) n. [L. pulpa, fruit-pulp.] 
The dental papilla ; the soft mass 
of splenic tissue (zool.} ; the soft, 
fleshy part of a fruit (bot.}. 

pulsating vacuole, a contractile 

pulse (puls) n. [L. pulsus, beaten.] 
The beat or throb observable in the 
arteries, due to the action of the 
heart (phys.). 

pulse wave, a wave of increased 
pressure over the arterial system, 
started by the ventricular systole 

pulsellum (pulseTum) n. [L. pulsus, 
beaten.] A flagellum situated at 
the posterior end of a protozoan 
body (zool.}. 

pulvillar (pulvil'ar) a. [L. pulvillus, 
a little cushion.] Pert, or at a 
pulvillus of an Insect (zool.}. 

pulvilliforni (pulvil'if&rm) a. [L. 
pulvillus, a small cushion ; fortna, 
shape.] Like a small cushion. 

pulvillus (pulvil'us) n. [L. pulvillus, 
small cushion.] A free pad or 
membrane under each claw of 
Diptera (zool.). 

pulvinar (pulvr'nar) n. [L. pulyinus, 
cushion.] An angular prominence 
on the optic thalamus (anat.) ; a. 
cushion-like ; pert, a pulvinus (bot.). 

pulvinate (pul'vinat) a. [L. pulvinus, 
cushion.] Cushion-like ; having a 
pulvinus (biol.). 

pulvinulus (pulvin'ulus) n. [L. pul- 
vinus, cushion.] A pulvillus. 

pulvinus (pulvr'nus) n. [L. pulvinus, 
cushion.] A cellular swelling at 
the junction of axis and leaf-stalk 

pulviplume (pul'viploom) n. [L. 
pulvis, powder ; pluma, feather.] 
A powder-down feather (zool.). 

punctate (pung'ktat) a. [L.punctum, 
point] Dotted ; having the surface 
covered with small holes or dots 

punctulate (pung'ktulat) a. [L. 
Punctum, point.] Covered with 
very small dots or holes (biol.). 

punctum (pung'ktum) n. [L. punctuw, 
point.] A minute dot, point, or 
orifice ; as puncta lacrimalia, puncta 
vasculosa (anat.) ; the apex of a 
growing point (bot.). 

puncture (pungTctur) n. [L.functura, 
prick.] A small round surface 
depression (btol.). 

pupa (pu'pa) n. [L. pupa, puppet.] 
The third or chrysalis stage of 




insect life ; the stage in insect 
metamorphosis preceding the imago 
or adult (zoal.). 

pupal (pu'pal) a. [L. pupa, puppet.] 
Pert, the pupa stage (zool.). 

puparium (pupa'rium) n. [L. pupa, 
puppet.] A coarctate pupa ; the 
pupal instar, exemplified in the 
blow-fly (zool.). 

pupiform (pu'p!f6rm) a. [L. pupa, 
puppet ; forma, shape.] Pupa- 
shaped ; pupa-like. 

pupigerous (pupij'firus) a. {L.. pupa, 
puppet ; gerere, to bear?) Con- 
taining a pupa (zool.). 

pupil (pu'pil) n. [L. pupilla, the 
pupil of the eye.] The aperture of 
the iris through which rays pass to 
the retina (anat.). 

pupillary (pupil'ari, pu'pilar!) a. [L. 
pupilla, pupil of the eye.] Pert. 
the pupil of the eye ; appl. a mem- 
brane (anat.). 

pupiparous (pupip'arus) a. [L. pupa, 
puppet ; parere, to beget.] Bring- 
ing forth young already developed 
to the pupa stage, as certain para- 
sitic Insects (zool.). 

Purkinje, cells of, an incomplete 
stratum of flask - shaped cells 
between the two layers of the grey 
matter of the cerebellum (anat.). 

pustule (piis'tul) n. [L. pustula, 
pimple.] A blister-like prominence 

pusules (pus'ulz) n. plu. [L. pus, 
matter.] Non-contractile vacuoles 
consisting of two sacs containing 
watery fluid, each emptying by its 
own duct, found in many Dino- 
flagellates_ (zool.). 

putamen (puta'mfin) n. [L. putamen, 
pod.] The hard endocarp or stone 
of some fruits (bot.) ; the lateral 
part of the lentiform nucleus of the 
cerebrum (anat.) ; the shell mem- 
brane of a bird's egg (zool.). 

pycnidiophore (piknid'iofor) n. [Gk. 
pyknos, dense ; pherein, to bear.] 
A conidiophore producing pycnidia 

pycnidiospore (plkmd'iospor) n. [Gk. 
pyknos, dense ; sporos, seed.] The 
spore produced by pycnidia (bot.). 

pycnidium (plknid'ium) n. [Gk. 
pyknos, dense.] A small flask-shaped 
organ or spermogoniurn containing 

slender filaments which form 
pycnidiospores or spermatia by 
abstriction, a stage in the life- 
history of wheat rust (bot.). 

pycnium, a pycnidium. 

pycnoconidium, pycnogonidium, 
pycnospore, varieties of pycnidio-