GLOSSARY 



443 



formed; opposetl to the •' trophoplasm " or nutritive plasm. (Strasburger, 

 1892.) 



[Lanthanin] {X-avBdvuv, to conceal), equivalent to oxychromatin. (Heidexhain, 

 1892.) 



Leucoplas'tids (Aci-ko?, white: TrXao-To?, form), the colourless plastids of plant- 

 cells from which arise the starch-formers (amyloplastids). chloroplastids. and 

 chromoplastids. (Schemper, 1883.) 



Linin (linum, a linen thread), the substance of the -achromatic" nuclear reticu- 

 lum. (SCHWARZ. 1887.) 



Lininoplast, the true nucleolus or plasmosome. (Eisen, 1899.) 



Macrocentrosome. a term applied to the " centrosome " in Boveri's sense, i.e. to 

 the larger body in which lies the central granule. (Ziegler, 1898.) Probably 

 svnonymous with entosphere. 



Maturation, the final stages in the development of the germ-cells. More spe- 

 cifically, the process by which the reduction of the number of chromosomes 

 is effected. 



Metakine'sis (see Metapliase) (jxtTa, beyond {i.e. further) : Kivvr](n?. movement), 

 the middle stage of mitosis, when the chromosomes are grouped in the equatorial 

 plate. (Flem.mixg, 1882.) 



Metanu'cleus. a term applied to the nucleolus after its extrusion from the germi- 

 nal vesicle. (Hacker, 1892.) 



Met'aphase. the middle stage of mitosis during which occurs the splitting of the 

 chromosomes in tlie equatorial plate. (Strasburger, 1S84.) 



Metaplasm (fxerd. after, beyond ; TrAaa/xa. a thing formed), a term collectively 

 applied to the lifeless inclusions (deutoplasm. starch, etc.) in protoplasm as op- 

 posed to the living substance. (Hansteix. 1868.) 



Micella, one of the ultimate supra-molecular units of the cell. (Nageli, 1884.) 



Microcentrosome. equivalent to the central granule or centriole of Boveri. 



(ZlECiLER, 1898.) 



Microcentrum, the centrosome or group of centrosomes united by a •• primary 

 centrodesmus," forming the centre of the astral system. (Heidenhaix, 1894.) 



Mi'cropyle (/xtK-pos, small : irvkr]. orifice), the aperture in the egg-membrane 

 through which the spermatozoon enters. [First applied by Turpex, in 1806, 

 to the opening through which the pollen-tube enters the ovule. /. Robert 

 Browx.] 



Mi'crosome (piiKpd?. small : awfrn, body), the granules as opposed to the ground- 

 substance of protoplasm. (Hansteex, 1880.) 



Microsphere, the central region of the aster (centrosphere) at the centre of which 

 lie the centrosomes. (Kostanecki and Siedlecki, 1896.) 



Middle-piece, that portion of the spermatozoon lying behind the nucleus at the 

 base of the flagellum. (Schweigger-Seidel. 1865.) 



Mid-body ("Zwischenkorper "), a body or group of granules, probably comparable 

 with the cell-plate in plants, formed in the equatorial region of the spindle during 

 the anaphases of mitosis. (Fle.mmexg, 1890.) 



Mi'tome (/xtrw/xa, from /xtros. a thread), the reticulum or thread-work as opposed to 

 the ground-substance of protoplasm. (Flemming, 1882.) 



[Mitoschi'sis (/xtVos. thread ; (rxL^f-i-v- to split), indirect nuclear division: mitosis. 

 (P'le.nemixg. 1882.) 



Mito'sis (/xtros. a thread), indirect nuclear division typically involving: a, the 

 formation of an amphiaster; d, conversion of the chromatin into a thread 

 (spireme) ; e, segmentation of the thread into chromosomes; d, splitting of the 

 chromosomes. (Flem.mixg, 1882.) 



Mi'tosome (/utVos, a thread; awijui, body), a body derived from the spindle-fibres 



