An important feature of these cells, in contrast with the finely granular cells elsewhere, is 

 their coarsely granular nature. They are more and more coarsely granular as we pass from the 

 inner to the outer margin. The outer half of these cells is thinnest and more coarsely granular 

 than the inner half. 



Notice also that the nuclei of these cells are in the first stages of division; i. e. they are 

 elongated radially and are faintly striated with a darker dotted line in the middle zone. The 

 achromatic spindle and stellate rays are not to be made out, the preparation not being favorable 

 to making out fine details of nuclear structure. 



These cells fit into the other floor-cells which arc shrunken away from them at this point. 



Fig. 4. One hour 30 minutes after 32-cell [stage], [pb = periblast). Section near middle. 



(87) Here the marginal cells are very distinct, but owing to method of treatment the subgerminal 



plate is very indistinct. Cap two cells deep at margin (sometimes two sometimes only one), 



three cells deep in middle. All the central cells from top to bottom are blackened alikr. 



Fig. 5. Transverse section near middle of 64-cell [stage], (30 minutes after 32-eell) Os and CrOa 3 



(85) da vs. 



The marginal cells are lighter and redder than the central, the latter being sUghtly more 

 tinged with osmic. The cells are closely packed and the subgerminal plate everywhere in 

 contact with cells except at one point where it "is broken. This is probably due to the con- 

 traction caused by the chromic acid. 

 Fig fj. One hour after 32-cell = fig. 1 in age). Transverse [section] near middle. (Os and Mk. 



(86) 3 days), [he = blastocoele; pb = periblast). 



The periblast is continuous under cap in most places. The marginal cells are distinct in color. 

 In all caps of this age, I find the central cells smaller than marginal and from two to three 

 cells deep; the marginal are from one to two deep. 



