224 JOHNS HOPKINS UNIVERSITY MORPHOLOGICAL MONOGRAPHS. 



in size and in their color so closely as to indicate that they are free nuclei, 

 and among these are still smaller deeply stained granules. Seeliger, 

 who believes that the number of embryonic eggs is very much greater 

 than the final number, regards them as abortive eggs, degenerating and 

 breaking up to supply material for the growth of the others, and he says 

 on page 36 that " the greater number of the cells of the ovarian string 

 either become abortive and unite as nutritive material with the devel- 

 oping egg cell, or else they form the follicle and the duct." Exact 

 numerical computation shows, however, that in Salpa pinnata, at least, 

 there is no such excess of ovarian eggs as he assumes. 



Salensky also believes in the occurrence of superfluous eggs, although 

 he disputes Seeliger's statement that they serve as food, as he says, 

 Pyrosoma, p. 79, " I have never met with degenerated egg cells in my 

 preparations of the genital string of salpa. On the contrary, I have 

 often seen that the young egg cells, which are unable to develop farther, 

 move towards the periphery of the ovary and arrange themselves among 

 the follicle cells. The structure of the cells is thus modified ; the nuclei 

 grow smaller, the protoplasm becomes more susceptible to staining fluids, 

 and their size diminishes. They become more and more like the follicle 

 cells and lie close among them. I have often seen such cells in the 

 haBmal part of the ovary, which ultimately becomes the oviduct, and 

 conclude from this that the superfluous egg cells become transformed 

 into follicle cells." 



My own view of the matter is that the cells in question are not egg 

 cells at all, but migratory follicle cells, which wander in among the eggs 

 and degenerate to supply them with food. My reasons for this view, 

 which appears to be the most simple and natural one, will be more 

 intelligible after I have described the process of migration and degen- 

 eration of the follicle cells at a later stage of development, but an exami- 

 nation of Plate XXXI, Figs. 5 and 6, shows, 1st, that the ordinary follicle 

 cells are in active multiplication ; 2d, that in the upper part of the follicle 

 the nuclei of certain cells exhibit evidence of degeneration, since they 

 lose their well-defined structure and become homogeneous, and stain 

 deeply and uniformly; 3d, similar cells are found in the yolk; 4th, 

 deeply stained bodies, like the nuclei of these cells, are also found free 

 in the yolk. In carmine specimens, in which both cell and nucleus 

 are deeply stained, one of these cells might be mistaken for a degen- 

 erating egg nucleus, but in good haematoxylin specimens, the larger 

 ones, which are about as large as the egg nuclei, are seen to be not nuclei 



