33 

 tori --.I and cuts off four s 



four underlying larger ones. ' f Lg. fig- 



ures a "blastoderm for the Trout which is almost 

 counterpart of this. K sectic - ;oderm in 



:■■- -. -' veals the structur L.II, 



"ere the two central cells stand above sal ones, 



ane of d Lally sharp, 



segmentation cavity fs.c.) central „ . 



are bo reduced. 



Another very common form of eight-celled blastoder 



.... - six cells below a 



a 

 two above. This is evi t srivative of a six-celled 



stage frequently Lth, i - blastomeres 



of Fig. 4 f Pi. I, divide by vertical furrows, the other two 



cell: Later, however, a division of 



these in a horizontal plane would give the structure sho 



ig. 11. - ii ire frequently due to 



the shifting of this pair of upper cells. gence 



is shown in Fig. 12, ?i. I., where these two cells reduced in 



size d,ed to one end of the longer axis of the "uiasto- 



placed parallel to the 



axis but over one of the cent- . . 



be shifted to lie at right angles to the long axis 



