124 



J. Thomas Patterson. 



1 



Fig. 1. — A two-celled stage, which was drawn from a free-haud sketch and 

 measurements of the living egg.= For the history of this egg see Table 1, hen 

 No. 2. X 18. 



Oi 





Fig. 2. — ^A median section taken transverse to the furrow of the egg illus- 

 trated in the preceding figure. The nucleus of Pander is very poorly developed 

 in this egg. c.n., cleavage nucleus, x 39. 



= In this, as in the succeeding figures of surface views, the anterior margin 

 of the blastodisc is toward the top of the page, and hence the median axis 

 of the later embryo will parallel the sides of the page. In sections the 

 anterior end is always toward the left. In the surface views the area occu- 

 pied by the primary cleavage, together with the first "ring"' of periblast, are 

 shown. 



