CLKAV.U1K PLANK AM) ENTRANCE POINT OF SPERM. 24! 



OBSERVATION-. 

 Outline of Development to First Clc<: 



Eggs in sea-water in which India ink has been previously 

 ground up show clearly the formation of the jelly, the formation 

 of the fertilixation cone, and the entrance of the spermatozoon. 



A -in-.ik i if ink points like a dagger or an exclamation point to 

 the entrance cone above which on tin- membrane the spermato- 

 /oon is .in. iched (Fig. 4). This "exclamation point" i- an aid 

 quickly to drtennine in a large number of eggs the relation of 

 the -perm entrance-point. The ^perma to/nun enter- the e^ .n 

 any point . ->. . also Lillie. 'i I . 



FIG. |. Firel clea> 



I 1 !'' i. l "in- and iii'lu.it 

 line Hi.uk- li"iiii' My. 



t"iiiiati"n. 15 ininutc~ .itu-r iii-rminut i"ii. ()utci 



This ink "exclamation p.-int." or ">perm indicator" as I shall 

 call it. i- a very in ten-Mil):; and striking formation worthy of 

 detailed smdv. With me. lunvever. the interest lay not SO much 

 in the lonnation of this indicator as in it- a\ ailability to help 

 ans\\cr the (itie-iion: \\hat is the relation of the sperm entrance 



