CHONDRIOSOMES IN CELLS OF FISH-EMBRYOS 475 



driosomes and of chondrioconts especially, which Corti repre- 

 sents in his drawings, suggests to me imperfect preservation. 

 Judging by Aunap's figure 4, it appears that the disposition of 

 the chondriosomes in the intestinal cells of the embryo of 

 Coregonus is quite different from what I found both in Fundulus 

 and in trout. 



I have also had the opportunity of making a few observations 

 in connection with the question of the primordial germ-cells. 



In embryos of Fundulus of three days and older, I found a 

 number of cells, the large size of which attracted my attention. 

 At nine days, the last stage I have studied, such cells can be 

 made out anywhere in the embryo (some are identified between 

 peritoneum and intestinal wall), but most of them are located 

 in the anterior region of the trunk, in the mesenchyme which 

 occupies the space comprised between pharynx and central nerv- 

 ous system. Felix and Biihler ('06) state that the primordial 

 germ-cells of the teleosts are remarkable because of their large 

 size and the lightness of their cytoplasm and nucleus. Aunap 

 ('13) (see also Dodds, '10) expressly mentions that these cells 

 do not contain any special yolk-granules nor centroteka, in con- 

 trast to the primordial germ-cells of birds. The cells I find in 

 Fundulus have these characteristics and furthermore, no other 

 cells were seen which could be considered primordial germ-cells. 

 Against their qualification as such, I must, however, mention 

 their close connection with the surrounding mesenchyme-cells 

 (fig. 7a) or with endothelial cells. This latter connection is so 

 •frequent that I at first thought these large cells were merely 

 endothelial cells seen in a tangential section of a vessel, — an 

 idea which for several reasons I was finally induced to drop. 

 Such connections have never been mentioned before, but on the 

 contrary, the majority of authors expressly state that the pri- 

 mordial germ-cells are round or oval, and not stellate, in shape. 

 I am unfortunately unable to decide as to the significance of these 

 cells, as, at nine days, no genital gland is yet developed in the 

 embryo of Fundulus. 



Another point of variation is the difference between the 

 chondriosomes of these cells and those described by Aunap in 



