The Cell in Development and Inheritance

His, W. — Unsere Korperform und das physiologische Problem ihrer Entstehung. Leipzig, 1874. Loeb, J. — Untersuchungen zur physiologischen Morphologie : I. Heteromorphosis. Wurzburg, 1891. II. Organbildung und Wachsthum. Wiirsburg. 1892. Id. — Some Facts and Principles of Physiological Morphology: Wood's El oil BioL Lectures. 1893. Morgan, T. H. — Experimental Studies of the Regeneration of Phanaria iMaculata : chen u. Leipzig, 1884. Roux, W. — tJber die Bedeutung der Kernteilungsfiguren. Leipzig, 1883. Id. — Uber das klinstliche Hervorbringen halber Embryonen durch Zerstorung einer

der beiden ersten Furchungskugeln, etc. : VirchoTifs Archiv, 114. 1888. Id. — Fiir unsere Programme und seine Verwirklichung : Arch. Entiu., V. 2. 1897. (See also Gesammelte Abhandlungen liber Entwicklungsmechanik der Organ- Whitman, C. 0. — Evolution and Epigenesis : Wood's H oil Biol. Lectures. 1894. Wilson, Edm. B. — On Cleavage and Mosaic-work: Arch, fur Entiuicklungsni., [Obsolete terms are enclosed in brackets. The name and date refer to the first use of the word; subsequent changes of meaning are indicated in the definition.]

Achro'matin (see Chromatin), the non-staining substance of the nucleus, as opposed to chromatin ; comprising the ground-substance and the linin-network. (Flemming, 1879.) A'crosome ( aKpov. apex, o-co/xa, body), the apical body situated at the anterior end of head of spermatozoon. (Lenhossek, 1897.) [Akaryo'ta] (see Karyota), non-nucleated cells. (Flemming, 1882.) Ale'cithal (d-priv. ; AcKt^os, the yolk of an egg), having little or no yolk (applied

to eggs). (Balfour, 1880.) Alloplasma'tic (aAAos, ditferent). Applied to active substances formed by dit^er- entiation from the protoplasm proper, e.g. the substance of cilia, of nerve-hbrillar, and of muscle-fibrillas. Alloplasmatic organs are opposed to •* protoplasmatic."' which arise only by division of preexisting bodies of the same kind. (A. Meyer. Aniito'sis (see Mitosis), direct or amitotic nuclear division ; mass-division of the nuclear substance without the formation of chromosomes and amphiaster.

(Flemming, 1882.) Am'phiaster {afxcj^L, on both sides ; dar-^p, a star), the achromatic figure formed in mitotic cell-division, consisting of two asters connected by a spindle. ( FoL. Amphipy 'renin (see Pyrenin), the substance of the nuclear membrane. Amy'loplasts (a/xyXov, starch: TrAao-ros, TrXdaaeLv. form), the colourless starch- forming plastids of plant-cells. (Errera, 1882.) An'aphase (am, back or again), the later period of mitosis during the divergence of the daughter-chromosomes. (Strasburger. 18S4.)

Aniso'tropy (see Isotropy), having a predetermined axis or axes (as applied to the egg). (Pfluger, 1883.) Anti'podal cone, the cone of astral rays opposite to the spindle-fibres. (\'an' Bexedex. 1883.) Archiam'phiaster (apxi- = first, + amphiaster), the amphiaster by which the tirst or second polar body is formed. (Whit.al-vx, 1878.) Ar'choplasma or Archoplasm (dpx(^^V' a ruler) (sometimes written <7rc////>/<is///). the substance from which the attraction-sphere, the astral rays, and the spindle- fibres are developed, and of which they consist. (Boveri, 1888.)

Arrhe'noid (dpprjv, male). The sperm-aster or attraction-sphere formed during the fertilization of the ovum. (Hexkix(j. 1890.) [As'trocoele] (dcTTrjp, a star: koiAo?. hollow), a term somewhat vaguely api)lied to the space in which the centrosome lies. (Fol, 1891.) As'trosphere (see Centrosphere). i. The central mass of the aster, exckisive of the rays, in which the centrosome Hes. Equivalent to the '• attraction-sphere " of Van Beneden. (Fol, 1891 ; Strasburger, 1892.) 2. The entire aster exclusive of the centrosome. Equivalent to the "astral sphere" of Mark. (BovERi, 1895.)

Attraction-sphere (see Centrosphere), the central mass of the aster from which the rays proceed. Also the mass of '^ archoplasm,'' derived from the aster, by which the centrosome is surrounded in the resting cell. (Van Beneden, 1883.) [Au'toblast] (avrds, self), applied by Altmann to bacteria and other minute organ- isms, conceived as independent solitary "bioblasts." (1890.) Axial filament, the central filament, probably contractile, of the spermatozoon- flagellum. (Elmer, 1874.)

Basichro'matin (see Chromatin), the same as chromatin in the usual sense. That portion of the nuclear network stained by basic tar-colours. (Heidexhain, Bi'oblast (/3tos, life : ^Aao-ro'g. a germ), a term applied by Altmann to the hypo- thetical ultimate vital unit (equivalent to plasome), and identified by him as the "granulum." Equivalent to the pangens of De Vries, the plasomes of Wiesner, etc. (Weismann, opposed to ''formed material." Nearly equivalent to protoplasm in the wider

sense. (Beale, 1870.) Bi'oplast. equivalent to cell. (Beale, 1870.) Bi'valent. applied to chromatin-rods representing two chromosomes joined end to plant-spermatids in connection with which the ciha of the spermatozoids are formed. (Webber. 1897.) Cell-plate (see Mid-body), the equatorial thickening of the spindle-fibres from which the partition-wall arises during the division of plant-cells. (Strasbur- more precisely defined by R. Hertwig. 1876.] Central spindle, the primary spindle by which the centrosomes are connected, as

opposed to the contractile mantle-fibres surrounding it. (Hermann, 1891.) Cen'triole. a term applied by Boveri to a minute body or bodies (" Central-korn ") within the centrosome. In some cases not to be distinguished from the centro- some. (Boveri, 1895.) Centrodes'mus (KeVx/oov, centre; Ses^o?, a band), the primary connection between the centrosomes, formed by a substance from which arises the central spindle. (Heidenhain, 1894.) Centrodeu'toplasm, the granular material of the testis-cells which may contribute

to the formation of the Nebenkern or to that of the idiozome. (Erlanger, Centrole'cithal (KcVrpov. centre : Acki^os, yolk), that type of ovum m which the deutoplasm is mainly accumulated in the centre. (Balfour, 1880.) Cen'troplasm (Kevrpov. centre; irXdo-fxa), the protoplasm forming the attraction- sphere or central region of the aster ; the substance of the centrosphere. (Er- langer, 1895.) Cen'trosome (Kevrpov, centre ; o-w/xa, body), a body found at the centre of the aster or attraction-sphere, regarded by some observers as the active centre of cell- division and in this sense as the dynamic centre of the cell. Under its influence arise the asters and spindle (amphiaster) of the mitotic fi-nire (Boveim

Cen'trosphere. used in this work as equivalent to the " astrosphere " of Stras- burger; the central mass of the aster from which the rays proceed and within which Hes the centrosome. The attraction-sphere. [Stkasburger, 1892: applied by him to the " astrosphere " and centrosome taken together.] ' Chloroplas'tids (xAwpoV green; TrAao-ro?, form), the green plastids or chlorophyll- bodies of plant and animal cells. (Schimper, 1883.) Chromatin (xpw/xa, colour), the deeply staining substance of the nuclear network and of the chromosomes, consisting of nuclein. (Fle.m.minc;. 1879.)

Chro'matophore (xp^/xa, colour; -cf>6po^, bearing), a general term ai)plied to the coloured plastids of plant and animal cells, including chloroplastids and chromo- Chro'matoplasm (xpoifxa. colour; irkacrixa, anything formed or moulded), the sub- stance of the chromoplastids and other plastids. (Strasrurger, 1882.) Chro'miole, the smallest chromatin-granules which by their aggregation form the larger chromomeres of which the chromosomes are composed^ (Eisex, 1899.)

Chro'momere (xpoj/xa, colour; /xepos, a part), one of the chromatin-granules of which the chromosomes are made up. Identified by Weis.manx as the "id." See Chromiole. (Fol, 1891.) Chromoplas'tids (xpoj/xa, colour ; TrAao-ro's, form), the coloured plastids or pigment- bodies other than the chloroplasts, in plant-cells. (Schimper. 1883.) Chro'moplasts, net-knots or chromatin-nucleoli : also used by some authors as equivalent to Chromoplastid. (Eisen, 1899.)

Chro'mosomes (xpa>/xa, colour: o-w/xa. body), the deeply staining bodies into which the chromatic nuclear network resolves itself during mitotic cell-division. ( Wal- deyer, 1888.) Cleavage-nucleus, the nucleus of the fertilized Qgg, resulting from the union of egg-nucleus and sperm-nucleus. (O. Hertwig, 1875.) Cortical zone, the outer zone of the centrosphere. (Van Benedex, 1887.) Cyano'philous (kwi/os, blue; ^lAetv, to love), having an especial affinity for lilue or green dyes. (Auerbach.)

[Cytoblaste'nia] (see Cytoblast), the formative material from which cells were supposed to arise by •• free cell-formation." (Schleidex, 183S.) Cytohy'aloplasma (kvtos, hollow (a cell) ; vaAo9. glass ; irXaafia. anything t"ormed), the substance of the cytorcticulum in which are embedded the microsomes: opposed to nucleohyaloplasma. (Strasrurger. 1882.) Cytomi'crosomes (see Microsome), microsomes of the cytoplasm : opposed to nucleomicrosomes. (Strasburger, 1882.)

Cy'toplasm {KVTo<i, TrXdafxa). i. The protoplasmic ground-substance as opposed to the granules. (Kolliker, 1863.) 2. Equivalent to protoplasm. (Kolliker, 1867.) 3. The substance of the cell-body as opposed to that of the nucleus. (Strasburger. 1882.) Cy'tosome (kvVos, hollow (a cell) : o-oj/xa. body), i. The cell-body or cytoplasmic mass as opposed to the nucleus. (Hackel, 1891.) 2. A term used as parallel to chromosome to denote deeply staining definitely organized cytoplasmic filaments or other cytoplasmic structures composed of "cytochromatin." (Prenant. 1898.)

Der'matoplasm {Sepfxa, skin), the living protoplasm asserted to form a part of the cell-membrane in plants. (Wiesxer, 1886.) Determinant, a hypothetical unit formed as an aggregation of biophores, determin- ing the development of a single cell or independently variable group of cells. (Weismaxx. 1 89 1.) [Deuthy'alosome] (8evT(epo^), second; see Hyalosome), the nucleus remaining in the egg after formation of the first polar body. (Vax Bexedex. 1883.)

Deu'toplasm (8et'T(e/oos), second ; TrAacr/xa, anything formed), yolk, lifeless food- matters deposited in the cytoplasm of the egg : opposed to "protoplasm." (Vax Bexedex. 1870.) Diakine'sis (8ta, through), the segmented-spireme-stage, following the synapsis, in the primarv oocyte or spermatocyte, during which the chromosomes persist for a considerable period in the form of double rods. (Hacker, 1897.) Dispi'reme (see Spireme), that stage of mitosis in which each daughter-nucleus has given rise to a spireme. (Flemmixg, 1882.)

Dy'aster (8m5, two; see Aster. 2), the double group of chromosomes during the anaphases of cell-division. (Flemaiixg, 1882.) Ectosphere (eKTo^, outside), the outer or cortical zone of the attraction-sphere. (Ziegler, 1899.) Egg-nucleus, the nucleus of the egg after formation of the polar bodies and before its union with the sperm-nucleus. Equivalent to the '"female pronucleus" of Van Bexedex. (O. Hertwig, 1875.) Enchyle'ma (ev, in; x^^^^' juice), i. The more fluid portion of protoplasm, consisting of " hyaloplasma."' (Haxsteix, 1880.) 2. The ground-substance (cvtolvmph) of cytoplasm as opposed to the reticulum. (Carxov, 1883.)

Ener'gid, the cell-nucleus together with the cytoplasm lying within its sphere of influence. (Sachs. 1892.) Entosphere, (evrog, inside), the inner or medullary zone of the attraction-sphere. (Ziegler, 1899.) Equatorial plate, the group of chromosomes lying at the equator of the spindle during mitosis. (Vax Bexedex, 1875.) Ergastic (epya^o/xat, to work). Applied to relatively passive substances '• formed anew through activity of the protoplasm.'' Equivalent to metaplasmic. C/. alloplasmatic. (A. Meyer, 1896.)

Ergastoplasm (epya^o/^ac. to work). Nearly equivalent to the '* kinopFasm '' of Strasburger and the •• ergoplasm '' of Davidoff. The more active protoplasmic substance from which fibrillar formations arise. (Gakniek, 1897.) Ergoplasm (epyov, work). The active protoplasm of the egg (in tunicatcs). mainly derived from the achromatic part of the germinal vesicle, and giving rise in jxirt or wholly to the polar spindle. Analogous to archoplasm and kmoplasm.

(Davidoff, 1889.) Erythro'philous (ipvOpoq, red; 4>Ly€tv, to love), having an especial affinity for red Ga'mete (ya/xexT/, wife ; ya/xerrys, husband), one of two conjugating cells. Usually applied to the unicellular forms. Gem'mule (see Pangen), one of the ultimate supra-molecular germs of the cell assumed by Darwin. (Darwix, 1868.) [Ge'noblasts] (yeVos, sex ; fSXaaro^, germ), a term applied by Minot to the mature germ-cells. The female genoblast (egg or '• thelyblast ") unites with the male

(spermatozoon or "arsenoblast") to form an hermaphrodite or indifferent cell. (Minot, 1877.) Germinal spot, the nucleolus of the germinal vesicle. (Wagner, 1836.) Germinal vesicle, the nucleus of the egg before formation of the polar bodies. (PuRKiNjE. 1825.) Germ-plasm, the same as idioplasm. (Weis.mann.) Heterokine'sis (erepo';, different), qualitative nuclear division ; a hypothetical mode of mitosis assumed to separate chromatins of different quality ; opposed to

homookinesis or equation-division. (Weismann. 1892.) Heterole'cithal (^'Tepo<i, different : keKLOoq. yolk), having unequally distributed deutoplasm (includes telolecithal and centrolecithal). (Mark, 1892.) Heterotyp'ical mitosis (erepo?, different ; see Mitosis), that mode of mitotic division in which the daughter-chromosomes remain united bv their ends to form Having little deutoplasm, equally distributed, or none. (Mark, 1892.) Homookine'sis or Homaeokine'sis (o/xo's, the same), equation-division, seijai.iung

equivalent chromatins : opposed to heterokinesis. (Weismann, 1892.) Homoeotyp'ical mitosis (o/xoto?, like: see Mitosis), a form of mitosis occurring in the secondary spermatocytes of the salamander, differing from the usual type only in the shortness of the chromosomes and the irregular arrangement of the daughter-chromosomes. • (Flemming, 1887.) Hy'aloplasma (vaXos, glass ; TrAatr/xa, anything formed), i. The ground-substance of the cell as distinguished from the granules or microsomes. [Hanstein, 1880.]

2. The achromatic substance of the nucleus in which the chromatin-particles are embedded. (Strasburger, 1882.) 3. The ground-substance as distinguished peripheral protoplasmic zone in plant-cells. (Pfeffer.) Hy'alosomes (vaAos, glass; a(ofxa, body), nucleolar-like bodies but slightly stained by either nuclear or plasma stains. ( Lukjanow, 1888.) [Hy'groplasma] {vyp(k. wet: 7rAao-/xa, something formed), the more li(juid part of protoplasm as opposed to the firmer stereoplasm. (Xageli, 1884.) Id, the hypothetical structural unit resulting from the successive aggivgation of

biophores and determinants. Identified by Weismann as the chromomere, or chromatin-granule. (Weismann, 1891.) Idant, the hypothetical unit resulting from the successive aggregation of biophore.s. determinants, and Ids. Identified by Weismann as the chromosome. (Weis- Id'ioblasts (t'Stos, one's own; /^Aacrrd?, germ), the hypothetical ultimate units of the cell; the same as biophores. (O. Hertwig, 1893.) Idioplasm (i,'8ios, one's own ; TrAacr/Aa, a thing formed), equivalent to the germ- plasm of Weismann. The substance, now generally identified with chromatin, which by its inherent organization involves the characteristics of the species. The physical basis of inheritance. (Nageli, 1884.)

Idiozome (tSto?, specially formed; ^oyfxa, girdle). The sphere, often called attrac- tion-sphere and usually enclosing the centrosomes, found in the spermatids of animals. (Meves. 1897.) Interfilar substance, the ground-substance of protoplasm as opposed to the thread- work. (Flemming, 1882.) Interzonal fibres ('• Filaments reunissants '' of Van Beneden. " Verbindungs- fasern " of Flemming and others). Those spindle-fibres that stretch between the two groups of daughter-chromosomes during the anaphase. Equivalent in some cases to the central spindle. (Mark, 1881.)