UN: ntO( M 01 i.i .\ 



In tl T the l-'i.-L''- 'illy, we find it in tin- i 



| i-mented hemisphere. \vliidi i> turn d upuard. 



When iti tliis c:t>e tin- nucleus prepaie> to divide, i'- Q no 



longer a;ime tin- position of any and every ladius of the egg. In 

 con.-etpicnci' of tin- \vant of uniformity in tin- di-t riluit ion f the 



protoplasm. the lUK-leUS collies Ulld'-r the illlliK 'lie 111 >le 



protoj lasmic pigmented part, \\liich nsfs on the more deutopl.ismic 

 I" ii 'On like an inverted cup, and. on a< count of its less >|.ecitic 

 :i:i\i!y. floats at tlie suiface. and is sjnvail out liori/.ontally. lint 

 in a in ri/on<al j)rot(.[)lasmic disc tlie nuclear spindle comes to OC'Ciij.y 

 a lioi-i/.cnial position (liir. '51 -' - v y). Cousequently the plane of 

 division must be formed in a vertical direction. A small furrow now 



x^V^X 



f ---V pr 



^ I ' 



Tig. 31. Diagram of the division of the Frog's egg. 



6 of tlif tir-t di\ i.-inM. />. St.u-i 1 f tin- third division. Tin- fmir x-iiint-nt .> f the second 

 f division :uv l.--iiiiiiM',' I" \n- dividrd l>y an -t[U.it"i i.tl furmw int<> ri-ht seginenU. 

 M' <"4- at tin- animal \>\<.- : /' ''"' l' ;ilt "'' ''" ' -'-' "hich is riclier 

 in j)rut<>iilas;ii ; </. tin- i>art lii^li is riilicr in d-ir -.dlo. 



>how itself at the animal pole lir>t, l.e,-au-e the latter ix 

 more under the inllucnce of the nuclear spindle, which li 

 to it, and l.eciiive it contains more protoplasm, from which proceed 

 the i-heii( meiia (f motion during division. The furrow gradually 

 deepens downward, and cuts thn.uiji to the vegetative pole. 



I'.y the fii:-t act of division we get two heii;i>phe: _'-), ( ach 



f \\ liich is composed of a ijuatlrant richc-r in protopla>in and directed 

 upward, and another poorer in protopla>m and diiec'el ilownwaid. 

 By this meailS both the position ( f the nucleus and the direct ii n of 

 its a\i> are again determined, when it prepares for the second 

 division. A< cording to the rule previously laid tlown, the inu-leii- i^ 

 to he .souglit in the quadrant which i oiitains the more protopla 

 the axis if the spindle mot take a petition parallel to the lon.i: 

 axi of the (juadrant, and must therefore come to lie horizontally 



