PRELIMINARY GENERAL SKETCH 



189 



form during extrusion of the polar bodies. The two types just 

 described (Fig. 96) are connected by various gradations. Thus, 

 in the lamprey, the frog, the rabbit, and in An.pln.xus one polar 

 body is expelled before, and one after, the entrance of the sper- 

 matozoon ; in the annelid Othryotrocha, entrance takes place when 

 the first polar spindle is in the stage of the equatorial plate ; 



/ 



T<,4»'us,e,, X icoo. (For later stages see t .g.^S^.)^ ^^^^^^^^^^ ^^ ^^^ sperm-nucleus against the 



A. Union of the nuclei ; extension 

 egg-nucleus ; division of the aster. 



of the aster. B. Flattening 



