194 



semblance to the preceding example in one feature. Nearly all its 

 germ -cells are represented by large products or megaspheres, each 

 equal to 4 or 8 ordinary germ-cells. 



There are in all at least 64 large germ-cells or megaspheres, many 

 of them being somewhere or other along the germ-path. In addition 

 there are 70 single germ-cells of 0.02 mm on each side of the body. 

 Allowing the right proportion of ordinary primary germ-cells for each 

 of the large products, we obtain: 



Germ-cells in the mid-line ... 4 



„ „ on the actual left side . 265 



„ „ „ right side 189 



458 



The result of a previous, but less exact, count gave 442. The 

 missing ones, required to bring the number up to 511, must have 

 been somewhere or other in the part of the blastoderm and yolk- 

 surface not preserved, but 13 or 14 megaspheres would suffice. 



Raja batis no. 745, In this, the representative of a 10 mm em- 

 bryo, the actual left side of the body is deficient. As in the first two 

 cases, for some reason or other the germ-cells are crowded into the 

 defective side of the body. It was impossible to enumerate them here, 

 owing to the numerous large clumps formed by them. But in the 

 whole embryo on the actual right side of the body there 

 are in all 11 germ-cells, of which 4 only are normally 

 placed. 



Kaja batis no. 746. There are several gill -clefts. Part of the 

 head is absent. There are no traces of eyes, ears, or nose, or of the 

 regions associated with these. In addition, the actual left side of the 

 embryo is somewhat dwarfed. Judging by the number of germ -cells, 

 this was probably an arrested potential female. In some points, such 

 as the well developed germinal nidus, it represents a much older em- 

 bryo, and one of more than double the size. 



The attempt to tabulate and enumerate the aberrant germ -cells 

 was abandoned as impossible. They occur all over and in every con- 

 ceivable place. There are very many of the normal size upon the 

 somatopleure, and also two large ones of 0.036 mm. 



The result of the census of normally placed gerni- 

 cells in this embryo reveals 46 on the right side of the 

 body, on the left only 14. 



