10 GEORGE T. HARGITT 



to all egg cells until they become very large; the position of egg 

 cells, deep in the tissues against the supporting layer, is also 

 characteristic. Another egg cell, ov, quite similar, but staining 

 less deeply, is present in the ectoderm. At a in the ectoderm 

 are cells which differ in certain respects from other ectoderm 

 cells, especially in a slightly more compact and deeper staining 

 cytoplasm and in having a nucleus somewhat larger than nuclei 

 of other ectoderm cells. If we may speak of these as primordial 

 egg cells just arising from the interstitial cells of the ectoderm, 

 it would suggest an ectodermal origin of egg cells in Eudendrium. 



Figure 8 — a continuation of the same stem shown in figure 7 — 

 shows at ov two small egg cells in the entoderm and none in the 

 ectoderm. These show all the characteristics enumerated for 

 the larger eggs just described. At various other places in the 

 sections of the same stem similar cells are found, both in ecto- 

 derm and in entoderm. In the entoderm gland cells (fig. 7, gl.) 

 might be mistaken for egg cells, but their shape and position 

 differentiate them, even though the staining capacity is some- 

 what like that of egg cells. Many other cells from a similar 

 portion of colonies, as well as from regions adjacent to hydranths 

 and gonophores, showed these egg cells. The very large eggs 

 were always in the entoderm, but as there were also small cells 

 in the entoderm and some undoubted egg cells in the ectoderm 

 which were larger than some in the entoderm, it is not possible 

 merely on the basis of size to determine which layer is the seat 

 of origin of the eggs. 



Figure 9 is from a transverse section of a portion of a stem 

 at the place of junction with the stalk of a hydranth and de- 

 veloping gonophores. In the entoderm is a very large growing 

 egg and at ov in the ectoderm (lower right side of figure) is a 

 small cell which has much the appearance of an oocyte at the 

 very beginning of its growth period. The deeply staining cyto- 

 plasm, the large, richly chromatic nucleus, the spireme or loop- 

 like character of the chromatin, have every appearance of cells 

 found in other coelenterates which were interpreted as some 

 phase of synizesis or synapsis. This cell can hardly be an 

 ectoderm cell in an ordinary division, since it is the only cell 



