[25] ■^'^'^•''MbM)MapM' M^8M6d¥'^ME^:''-' 479 



wrinkle, becomes gTiidually tliiiiiierj'an'ciflhally disappears altogether; 

 the already numerous nucleoli become still more so, but also smaller 

 and smaller, uiitir tKey ar^ 'finally indi^^^^^ so that one' is 



obliged to conclude tliat tliey iiavelDeen dissolved in the intranuclear 

 fluid, finally, the nucleus is brought to lie close against the zona ra- 

 diata, as a wall-less, irregular, viscousV almost homogeneous mass; the 

 inti'ahuclear flliicl' in which tiie nucleoli hWo been dissolved now begins 

 to mix with the egg contents. Accompanying this blending important 

 changes occur, and, as a result of the process, the direction si)indle, the 

 nucleus, and the yelk are difierehtiated. In the pellucid ova of /Scor- 

 pwna the yelk spherules are a^'aiu broken down and the food-yelk 

 then forms a clear, semi-tluid mass; in Jidis, ^crranxs, and Fiems/er, 

 the clear yelk also contains a large, shining oil-sph.ere; in Ct'ciiilabrus 

 the yelk is hot entiretj'^ pellucid', biitcidnttiihs some, not v^y hiirheJCQus, 

 yelk granules ; in the herring and iTen as i s thoi yv\k contaius a great 

 number of yelk spherules, but which, in consccpience of their larger 

 size and less bright appearahce,^Ioc»k' 'Very differently from' tlie yelk 

 spherules of the immature 'cg'ixi - , ■ . . ..:, ^ ^ . ^^ • - ^^ • 



"The direction spindle [polar ^spititite] Ijas^iis'^i^eTiplierM 

 immediately agaiiist the inner opening of the niicropyle. It is best seen 

 in Scorpwna, in which it has a 'length' of .025°'"', and a diameier of 

 .0145'"™; its longitudinal axis forms an angle of 45'^ with that of the 

 axis Of the egg. It is lesS easily Imacte 6nt in Jlt/^ ^w^^^ 

 Crenilahrus, JlcUasis, Gohlkis, Blennius', iBclonc, Clupea, arc too unsatis- 

 factory and opaque as objects in which to seek for, the direction spin- 



die. ^-;i^ r;:';^::'';V:^n^'^'r ' ph.'!-.'^^^ . 



"The form of tlie' ^(irttVlii 'tSe' rnature taken frohrlhe female^' of 



different species, without being brought into contact with water, is very 

 different. In Julis it surrounds, as a relatively thick layer, the entire 

 yelk, and is thickest at the uiicropylar pole of the {^^gg; in Bcorimna 

 it covers in a caip-like manner the micropylar pole of the yelk where it 

 is thickest, and becomes gradually thinner towards the equator, where 

 it disappears almost Avholly, but is continued over the opposite pole^^^as 

 a diistinct but very" thiii'layer. fn fhe eggs of the herring and Heliasis 

 it docs not form a very thick stratum beneath the luicropyle, and extends 

 from this region as irregular fhick apid thin processes down amongst the 

 yelk spheres'' t/ft'Ue'''#tlbr(^'e^g^^ '^i'iie'^jrect^on spindle ^ a is always 

 Imbedded in 'tile "geinh 'disir.' ' ' I^upffer's statement that the germ pf t-^lie 

 herring is developed under the inlluence of the ,sea-water and the s^jeym 

 rests upon inaccurate observations; in the uuimpregiiated,e^"g pf, flie 

 herring, as in Heliasis, tha germinal matter still remains in greatpart 

 strewn amongst the yelk spherules, as is apparently the case with all 

 eggs in which the yelk does not consist of fluid material,.bu^^ 

 ptitt of larger and smaller yelk spherules.. ,,,',,.. ,,,.,,.. ,jj,, .jin,. ,!,'.: 

 '" The" fact tliat the yelt spherules , of jpejai^W^'g^^^ 

 ^^'IM^ieil'llowu Vind in niatiii^ eggs beicrfme'clear aiid pellucid throughout 

 must probably be regarded as a phenomenon of adaptation, the whole 



