nucleolus 
the network (Klein). The nuclenlim of the human ovum 
was discovered by \Vaii'T in iva;, :iml hence i*s<nu< -linn - 
eallcd tlie *i*tt of Within'/- in aiiatninlral text-tn,okH. See 
cut under ctU, 6. 
A large, clear, spherical nucleus is seen In the interior 
of the nerve-cell ; HIK! in tin- centiv of this i.- a well-deilm d 
small round particle, the nuclei/tun. 
Uuxley. Crayfish, p. 187. 
St. Specifically,' in Iufn.inriti,i\ minute particle 
attached to the exterior or the nucleus (or 
"ovary"), supposed to function aw a testicle. 
But since It Is the essential characteristic of a nucleolus 
to be contained within a nucleus, these Bo-called nucleoli 
of protozoans are now differently Interpreted, and called 
paranuclei. See paranuclr tu, 
3. In hot., a small solid rounded granule or 
particle in the interior of the nucleus. There 
may bo several nucleoli in each nucleus. 
nucieoplasm (nu'kle-o-plazm), n. [<. L. nurli'n.i, 
a kernel, + NL. plasma = E. plamn.] The more 
fluid part of the nucleus, found between the 
nuclear threads. See nucleus, 1 (a). 
nucleoplasmic (nu*kle-o-plaz'mik), n. [< ni<- 
cleiijilaxm + -ic.j Pertaining to or of the nature 
ill' nurlr)>hism. 
nucleospindle (nu'kle-o-8pin*dl), . [(. L. nu- 
cleus, a kernel, + E. spindle.] The nucleus- 
spindle; a fusiform figure occurring in karyo- 
kinesis, formed of striated achromatin figures, 
and often bearing pole-stars at each pole. 
nucleus (nu'kle-us), n.; pi. nuclei (-i). [< L. 
nucleus, a little nut, a kernel, the stone of a 
fruit, for "nuruleus (cf. equiv. nucitla), dim. of 
nux (nuc-), a nut. Not related to E. nut.'] 1. 
A kernel; hence, a central mass about which 
matter is collected, or to which accretion is 
made ; any body or thing that serves as a cen- 
ter of aggregation or assemblage ; figuratively, 
something existing as an initial or focal point 
or aggregate : as, a nucleus of truth ; a nucleus 
of civilization. 
Then, such stories get to be true In a certain sense, and 
Indeed in that sense may he called true throughout ; for 
the very nucleus, the fiction In them, seems to have come 
out of the heart of man in a way that cannot be Imitated 
of malice. Hawthorne, Septimius Felton, p. 111. 
The regiments fashioned by his [Cromwell's] master 
hand, steady, perfectly ordered, and enthusiastic in their 
cause, became the nudeua of the far-famed Ironsides. 
Edinburgh Ret}., CLXV. 466. 
(a) In '"'/. the kernel of a cell, in general; a central or 
Interior differentiated mass of protoplasm, found in near- 
ly all cells, vegetable or animal, and consisting of an oval 
or rounded body composed of (1) a nuclear membrane, (2) 
nuclear network, and (3) nucleoplasm, and containing 
nucleoli. The nuclear network is made up of threads 
or fibrils which are composed of a deeply staining part, 
"chromatin," and a feebly staining intermediate substance, 
"linin " or parachromatin (nucleohyaloplasm). In the 
meshes of the network is found the more fluid part of 
the nucleus, the nucieoplasm (achromatin, karyochylema, 
paralinin). Nucieoplasm, according to Carnoy, consists 
of a plastin network and a granular fluid, "enchylema." 
The nuclear membrane la considered by some observers 
to be an inner limiting layer of cell-protoplasm surround- 
ing the nucleus, by others to be a condensation of the 
peripheral portion of the nuclear network. There may 
be but one nucleus or several nuclei in one cell; and a 
nucleus may be nucleolate or not. Nuclei are generally 
proportionate in size to the cell containing them ; in some 
instances, however, they form almost the entire cell-mass. 
A structural difference between the nucleus and the rest 
of the cell-protoplasm is indicated by Its greater resist- 
ance to powerful reagents, and by its varied reaction with 
status. Functionally, the nucleus is the most important 
portion of the cell, as it is here that the complex series of 
changes known as karyokinesis take place, resulting in 
the division of the nucleus and followed by the division 
of the cell. This process of mitosic or Indirect cell-divi- 
sion is found In all varieties of cells, whether vegetable or 
animal, fetal or adult, normal or pathological. Instances of 
cell-division not mitosic have, however, been noted. The 
nucleus of the human ovum was discovered by Purklnje 
in 1825, and hence is often called the corpuscle of Purltinje. 
Its usual name in text-books of anatomy is germinal vesi- 
cle. See cut under cell, 5. (b) In zool. : (1) In ascidians, the 
alimcntm-y and reproductive viscera collectively, when 
these are aggregated into a mass, as in the sains. (2) In 
protozoans, a solid rod-like or strap-shaped body, having 
In many cases the functions of an ovary in connection 
with a nucleolus (see nucleolus, 2). (3) In echluoderms, 
the madreporiform body, (c) In mutt., a collection of 
ganglion-cells in the brain or other portion of the cere- 
hrosplnal axis, (d) In conch., the embryonic shell which 
remains at the apex of the mature shell, as of a gastro- 
pod; also, the initial point from which the opereuluiu of 
a gastropod grows. See protoconch. (e) A body having a 
stronger or weaker attraction for the gas, vapor, or salt 
of a solution than for the liquid part of it, and therefore 
modifying by its presence the freezing- and boiling-points. 
Jtiaater. (/) In a*tni., the bright central point usually 
present in the head of a comet and often in a nebula. 
H. [cap."] A genus of gastropods: same as 
Colunibrllii. Aoriotw, 1 s '-"-. Accessory auditory 
nucleus, the group of ganglion-cells situate. 1 at the junc- 
tion of the lateral and median roots of the auditory nerve. 
Also called rrntt'i-tor auditor'/ nitcldt*. lateral nucleus of the 
medial root, ganglion of the auditory nerve, nucleus aoumo 
rius acustifi. and H"r/.>^ r<'fh{>'ftr\x. Amygdaloid nu- 
cleus. same as ni/"/;;-/ri?,i, 4. Caudate nucleus. See 
caudate. Cervical nucleus, a group of ganglion-cells 
opposite the origin of the roots of the third and fourth 
4035 
cervical nerves, and corresponding in position to Clarke's 
column. Clavate nucleus. se rforti. External 
accessory olivary nucleus, a short band of gray matter 
in tile ret ieulai i" u't i" .1, just dorwid of the nucleus olivaris. 
Also called superior or lateral accessory olivart/ nucleus. 
Inferior auditory nucleus, that part of the accessory 
mi 1. us which lie* between the two auditory root*. 
Inner accessory olivary nucleus, an elongated col- 
lection of gray matter lying Just behind the pyramid 
and t., the inner \< ntlal .-ide of the (lower) olive. Also 
called anterior accessory olivary nucleus and pyramidal 
nucleus. Lenticular nucleus. See lenticular. Nuclei 
arcuati. small collections of gray matter near the ven- 
tral surface of the pyramid, beneath and among the 
external arcuate fibers. The largest group forms the 
nucleus arcuatwt triangularis, or nucleus arctftrnnis, or 
ni"-t>"< //'/''"""V"'''*' "nfi /-ii'i'. AN' r.illcd ntn-l.i 1 tl,.' 
ttftrtcinl in-rn:il, ;/',.,. Nuclei IClllIlisci 1110(lj:iliH, 
small groups of ganglion-cells in the Immediate vicinity 
of the lemniscus medialls.- Nucleus abducentis, the 
nucleus of origin of the abducens nerve, a round mass 
of gray matter In the lower part of the pons, near the 
fioor of the fourth ventricle and not far from the middle 
line. Nucleus amblgllUB, a tract of large ganglion-cells 
in the substantia reticularis grisea of the oblongata. It 
furnishes fibers to the vagus and glossopharyngeus ; other 
fibers from it turn toward the raphe. It is continued up- 
ward as the facial nucleus. Also called nucleus lateratis 
tnedius. Nucleus amygdalae, a rounded gray moM con- 
tinuous with the cortex of the tip of the gyrus hippocampi, 
projecting Into the end of the descending comu of the 
lateral ventricle. Also called amygdala and amygdaloid 
tubercle. Nucleus anterior thalaml, the gray matter 
of the thalamus corresponding to the anterior tubercle, 
separated from the inner ana outer nuclei by septa of 
white matter. Also called nucleus superior thalami, nu- 
clcusofthe anterior tubercle, and nucleus caudatus thalami. 
Nucleus bulbi fomicis, the gray matter within a cor- 
pus albicum. Nucleus caudatus, the caudate nucleus, 
the upper ganglion of the corpus striatnm, separated 
from the lenticular nucleus by the internal capsule. Also 
called the intraoentricular ganglion of the stnate body. 
Nucleus centralis Inferior, a group of ganglion-cells 
in the substantia alba of the upper part of the oblongata 
and lower part of the pons, between the lemniscus and the 
posterior longitudinal fasciculus, on both sides of the 
middle line. Also called nucleus centralis of Roller. Nu- 
cleus centralis superior, a collection of ganglion-cells 
in the tegmentum of the upper part of the pona, on either 
side of the middle line and between the posterior longitudi- 
nal fasciculus and the decussation of the superior pedun- 
cles of the cerebellum. Nucleus cuneatus externus, 
a small separate gray mass external to the principal nu- 
cleus funieull cuneatL Nucleus dentatus. Same as 
corpus dentatum (a) (which see, under corpus). Nucle- 
us dentatus cerebelli, the convoluted shell of gray 
matter lying in the white substance of either hemisphere 
of the cerebellum, and open on its median side. Also 
called corpus dentatum cerebelli. nucleus denticulatus, nu- 
cleus Amlrriatus, nucleus lenticulatus, corpus ciliare, corpus 
rhoniboideuin, and corpus rhomboidale. Nucleus embO- 
lifonnis, a clavate mass of gray substance lying mesially 
to and partially covering the hilum of the nucleus denta- 
tus cerebelli. Also called embolus. Nucleus externus 
thalaml, the gray matter of the outer part of the thala- 
mus, extending posteriorly into the pulvinar, and sepa- 
rated from the inner nucleus by the lamina medullaris 
medialis. Also called nucleus lateralis thalami. Nucleus 
funieull anterioris, a group of large ganglion-cells lying 
on the median side of the hypoglossal roots, at about the 
middle of their course through the oblongata. Also called 
nudeusofanteriorroot-zone. Nucleus funiculi cuneati, 
the body of gray matter with ganglion-cells in the upper 
end of the cuneate funiculus. Also called cunealr nucleus 
and restiftrnn nucleus. Nucleus funiculi lateralis, the 
separated part of the anterior cornu of the spinal cord 
continued into the oblongata, lying in the lateral column 
near the surface, behind the olivary nucleus. Also called 
nucleus anterolateralis, nucleus lateralis. Nucleus funi- 
culi teretls, a tract of fusiform ganglion -cells lying close 
to the middle line and close to the surface in the funi- 
culus teres of tin floor of the fourth ventricle. Also called 
nucleus medialis. Nucleus glODOSUS, a small round mass 
of gray matter between the nucleus emboliformis and the 
nucleus tecti. Nucleus internus thalaml, the gray 
matter of the inner part of the thalamus, separated from 
the outer and anterior nuclei bytepta of white matter. 
The Internal nuclei of the two sides are united by the 
middle commissure. Also called nucleus medialis thalami. 
Nucleus lateralis. (a) The nucleus funiculi lateralis. 
(6) Same as claustrum, l. Nucleus lemnlscl lateralis, a 
collection of ganglion-cells in the tegmental region of the 
upper part of the pons, close to the lateral surface, giving 
fibers to the lateral lemniscus. Nucleus lentlcularis, 
the lenticular nucleus, the lower layer nucleus of the 
corpus striatum, divided by medullary lamina- into three 
zones, the outer of which is called the putamen, while the 
two inner are called the globus pallidus. Also called the 
fxtraventricular ganglion of the striate body and nucleus 
lentifortnis. Nucleus of Bechterew, the ill-defined 
group of ganglion-cells lying dorsad of Deiters's nucleus, 
from which It is claimed by Bechterew that some of the 
fibers of the medial root of the auditory nerve arise. Also 
called nucleus angularis, principal nucleus of the nervus 
vestibulari*, and nucleus vestibularis. Nucleus Of Del- 
ters, a mass of gray matter containing large cells lying 
on the inner side of the restiform body, and giving origin 
to the medial root of the auditory nerve. Also called outer 
auditory nucleus, ascending root, medial nucleus of the me- 
dial root, and lateral part of the nucleus superior. Nucleus 
Of Luys, an almond-shaped gray mass with pigmented gan- 
glion-cells In the regio subthalamica. Also called corpus 
subthalamicum, Luys's body, nucleus amygdaltformis, and 
nucleus pedunculi cerebri. Nucleus Of Pander, the ex- 
panded extremity of the white yolk of an egg, beneath the 
blastoderm. Nucleus olivaris superior, a convoluted 
plate of gray matter lying dorsad of the trapezium, not 
prominent in man. It appears to be connected with the 
accessory auditory nucleus of the opposite and to a less de- 
gree of the same side through the trapezium, with the poste- 
rior quadrigemlnal body of the same side through the lat- 
eral lemniscus, and also with the abduccns nucleus of the 
same side. Also called nucleus dentatus partis commissu- 
nude 
raiu.anil upper or superior olivary body or Mce. Nucleus 
pontls, or, in the plural, nuclei pontia, gray matter 
with numerous small nerve-cells inclnd. d l,etueen the 
filters of the ventral or crustal part of the pons. Nucleus 
reticularis tegmentl pontls, an assemblage of acatter- 
i-d gungllon-fc!l in the pom, on both sides of the raphe, 
l,.tei -n the lemniseus and the posterior longitudinal faa- 
clculua, and cerebralward from the nucleus central!* in- 
ferior. Nucleus tecti, a small mass of gray matter in 
the white center of the anterior part of the vermls of the 
cerebellum, close to the median line on either side. Also 
called roof nucleus, nucleus fattigii, and substantia ferru- 
ginea superior. Nucleus trapezll, ganglion-cells acat- 
tered among the fibcra of the trapezium. Also called nu- 
cleus irapczoidcs.- Principal auditory nucleus, a gray 
mass of triangular cross-section, forming a prominence on 
the floor of the fourth ventricle (tuberculum acuatlcnm). 
The strite medullarea pans over It. Also called central, in- 
ner, or posterior nucleus, median nucleus of the lateral rtiot, 
and median portion of the nucleus superior. Pyramidal 
nucleus, the Inner acceaaory olivary nucleus. Eed nu- 
cleus, a mass of gray matter with numerous large pig- 
mented cells In the tegmentum of the crus cerebri. To 
It the superior cerebellar peduncle of the opposite side 
proceeds. Also called nucleus of the tegmentum, nucleus 
terrmenti, and tegmental nucleus. Restiform nucleus. 
Same as nucleus funiculi cuneati. 
Nucula (nu'ku-la), . [Nl., < L. nucnla, a 
little nut, dim. of nux (nuc-), 
a nut.] A genus of acepha- 
lous or conchiferous mol- 
lusks, formerly referred to 
the ArcitUe or ark-shells, now 
made type of the family Nu- 
eulidtr. The size is small, and the 
shape resembles that of a beech- 
nut, whence the name. There are 
about 70 living species, of which 
If. nucleus is typical, and numer- 
ous extinct ones, among which is A", cnbboldite of the Eng- 
lish crag. 
Nuculacea (nu-ku-la'se-a), N. pi. [NL., < A T - 
cula + -ncea.] A superfamily or suborder of 
bivalves, including the families Nuculidtc and 
Ledidai. 
nuculanium (nu-ku-la'ni-um), /.; pi. nuculania 
(-a). [NL.,< L. nucula, a little nut: see nucule.'] 
In Oof., a superior indehiscent fleshy fruit, con- 
taining two or more cells and several seeds, as 
the grape. 
nucule (nu'kul), . [< L. nucula, a little nut, 
dim. of nux (nuc-), a nut : see nucleus.] In Cha- 
racece, the female sexual organ. 
In ( 'hnraeea- the female organ has a peculiar structure, 
and Is termed a nucule. Encyc. Brit., IV. 158. 
Nuculidse (nu-ku'li-de), n.pl. [NL., < Nucula 
+ -idee.'] A family of bivalves, typified by the 
genus Ifiieula ; the nutshells. The shell la of small 
size and angular trigonal form. The cartilage is Internal, in 
a pit, and the hinge has two rows of diverging compressed 
teeth. The animal has a large discoidal foot, with a trans- 
verse serrate periphery ; the mantle-flaps are freely open 
and asiphonate ; the gills are small and plumiform. They 
are found In all seas, and have great geological antiquity. 
The family i- used with varying limits, and sometimes 
extended to include the Ledidai and various extinct rela- 
tives. 
Nuda (nu'dii), n.pl. [NL., neut. pi. of L. nudux, 
naked: see n udv,~\ A name that has been vari- 
ously used as that of an order or group of naked 
animals, (a) Naked reptiles, or batrachians, the third 
order of reptiles, corresponding to the modern Amphibia. 
Oppel, 1811. (t>) The "naked molluaks" of Cuvier thatls, 
the tunicories, ascidians, or sea-squirts, (c) Naked lobose 
protozoana, having no test, as ordinary amcebas. The ^'en- 
era Amoeba, Ouratnoeba, IMhamceba, Dinamaeba, and others 
are Nuda. (d)The term is also repetitively applied to sev- 
eral different groups of infusorians, members of each of 
which are classified as either Nuda or Loricata. 
nudatipn (nu-da'shqn), n. [< L. nuihitio(n-), a 
stripping naked, nakedness, < nudarc, pp. nuda- 
ttiK, make naked.bare, < nudus, naked: see nude.} 
The act of making bare or naked. Johnson. 
nuddle 1 (nud'l), . [Var. of noddfel.] The 
nape of the neck. Halliiccll. [Prov. Eng.] 
nuddle 2 (nud'l), r. i. ; pret. and pp. nuddted, 
ppr. nuddling. [Origin obscure.] To stoop in 
walking; look downward. [Prov. Eng.] 
Whether this proverb may have any further reflection 
on the people of this Country, as therein taxed for covet- 
ousness and constant nudliwt on the earth, I think not 
worth the enquiry. Ray, Proverbs (1678), p. S10. 
nude (nud), a. [= F. nu = Sp. nudo = Pg. MM 
= It. nudo, < L. H fid ii.i, naked, bare, exposed: 
nee nnked.'] 1. Naked; bare; uncovered; spe- 
cifically, in art, undraped; not covered with 
drapery: as, a nude statue. 
We shift and bedeck and bedrapc us ; 
Thou art noble and nude and antique. 
A. C. Swinburne. Dolores. 
2. In law, naked ; made without consideration : 
said of contracts and agreements in which a 
consideration is wholly lacking. 3. In hot. 
and rooV. : (a) Bare; destitute of leaves. h:tir>. 
bristles, feathers, scales, or other exterior out- 
growth or covering, (b) Not supported by diag- 
nosis or description ; mere ; bare : said of ge- 
