GLOSSARY 



443 



formed; opposetl to the " troplioplasm '" or nutritive plasm. (Stkashi'RGER, 

 1892.) 



[Lanthanin] (Aav^ctvetv, to conceal), equivalent to oxychromatin. ( Hi:idknhain, 

 1892.) 



Leucoplas'tids (AevKo?, white : TrAaoro?, form), the colourless plastids of plant- 

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

 chromoplastids. (Schlmper, 1883.) 



Li'nin (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. (Zikgler, 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 uf chromosomes 

 is effected. 



Metakine'sis (see Metaphase) (/xera, beyond {i:e. further) ; KLvvrjrrL^;. movement), 

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

 plate. (Flemming, 1882.) 



Metanu'cleus, a term applied to the nucleolus after its e.xtrusion from the germi- 

 nal vesicle. (Hacker, 1892.) 



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

 chromosomes in the equatorial plate. (Strasburger, 1884.) 



Met'aplasm (/xera, after, beyond; TrAacr/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.) 



Micel'la, one of the ultimate supra-molecular units of the cell. (N.ageli. 1884.) 



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

 (Ziegler, 1898.) 



Microcen'trum, the centrosome or group of centrosomes united by a '• primary 

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



Mi'cropyle (fjuKpo^, small: ttvXt], orifice), the aperture in the egg-membrane 

 through which the spermatozoon enters. [First applied by Ti'Ri'i.v, in 1806, 

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



Brown.] 

 Mi'crosome (fxiKpoq, small : croj/xa, body), the granules as opposed to the ground- 

 substance of protoplasm. (Hansteix, 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, i)robal)ly comparable 



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



the anaphases of mitosis. (Flemming, 1890.) 

 Mi'tome (/xtrco/xa, from ^tVos, a thread), the reticulum or thread-work as opposed to 



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

 [Mitoschi'sis (/xiro9, thread ; ax^C^i-v, to split), indirect nuclear division; mitosis. 



(Flemming, 1882.) 

 Mito'sis (iJLLTo<;, a thread), indirect nuclear division typically involving: u, the 



formation of an amphiaster: /\ conversion of the chromatin into a thread 



(spireme) : r, segmentation of the thread into chromosomes : (/. splitting of the 



chromosomes. (Flemming, 1882.) 

 Mi'tosome (^tros, a thread; aCjfxa, body), a body derived from the spindle-fibres 



