eontrmry, pru^sent at one of their polea a little bud, the sue ot" which 

 inereaaea until it becomes eijual to that ol" the maternal cell ; one 

 of the nuclei poiMea to the interior ot" the bud, and thenceforward 

 we m-iv r^'t'o-^i/e two cells, separated from each other by a circular 

 con- . deepens ^radmUly ; the two dau>rhter cells be- 



WKii d. but remain clo«ely conncctetl with each other. 



The two celia. therefort>. are produced by division from a primitive 

 mother ct [!. I have alwavs found it impoisisible to diatin^ruish any 

 trace of rane about these youn>r ovules. 



It is ic .- , • le here to make two observations : — first, that these 



mother cells occur in great (juantity in the ovaries immediately after 

 OTip»>«ition, a8 may be seen from the fact that the ovisacs contain 

 eggs which are still at the first commencement of embryonic deve- 

 lofvmi^nt ; secondly, that the dimensions of the mother cells are the 

 same as those of the little cells which are found in the form of an 

 emiiueiiice situated at one of the poles of the mature eg^. All the 

 other ehAracters of the mother cells are identical with thtwe which 

 mn presented by these polar cells of the mature e'j:»»s. In both we 

 ace a perfectlv transparent protoplasmic body, holdinj; in suspension 

 sioin' ve jylobidcs. and we even find some of 



eoTi- >>sent no difference in ch.iracter from 



tlio«4f u: .,;■.. We distins»uish in them a vesicular nucleus, 



with vei-v outlines, providevl witlx a nucleolus endowed with 



coDdiderubile retfuctive power. 



The mother cells of which I have spoken give origin, by means 

 of diTision, to two daughter cells. At the commencement of their 

 derelopment these cells are all exactly alike. Soon, however, their 

 bulk inereases slightly, and each of them ac<|iiires by degrees the 

 tonensioa"* of the mother cell. They each contain some refractive 

 globoles ; but soon the number of these globules increases greatly 

 in OBe of the two united cells, and, at the same time, its size begins 

 to exceed that of its congener. From this moment it becomes im- 

 poBsible to distinguish, in the miiist of th«»se refractive globules, the 

 nooleus of the enlarged cell. I have never afterwards succeeded in 

 ^,: . . u _, ^jj. jjj^, mature e^ the cell-nucleus in the midst of 

 the .uuss. The cell increases more and more ; it completely 



fills ir.-r lt w ich refractive globules, of which the size increases as 

 quickly as the number. Whilst enlarging, this cell ( which we may 

 now call the ^i/./. since we rtnogni/e distinctly in its contents the 

 chart! r^•^>* '^f v rrne virellnst preserves a perfectly regular spheroidal 

 for . les the second cell, which has remained 



sta; at. is attacheii. When the egg has at- 



tained .m U-I6-«>-l?^ millim. we distinctly recognize 



in it a . which is developed at the expense of the 



periphery of the protnpla-sm of the ovicell, and betrays itselt" by 

 its dark outline. This membrane (vitelline membnine) is not a 

 eommiin envtlope of the enlarged cell (which is the e^^ in course of 

 development I and of the transptvrent cell joined tt) one of its poles ; 

 it does not enclose this latter cell, but, ou the contrary, its contour 

 atopis at the margin of the surface of attachment of the egg and the 



