314 Elliot R. Downing, 



eggs and ovarian cells do not multiply longer, but the}' change so 

 that by a sort of degeneration on the part of the ovarian cells and 

 a cellular digestion on the part of the growing egg only the latter 

 remains (p. 285). The yolk-filled protoplasmic region of the egg forces 

 its processes into the spaces among the remaining ovarian cells in 

 order to reach them more easily; so the incorporation of the ovarian 

 cells into the egg is probably accomplished by the mobility of the 

 protoplasm. The egg nourishes itself just as a protozoan which 

 with its amoeboid protoplasm surrounds nutrition and takes it into 

 itself (p. 287). In the region where egg and ovarian cells are 

 sharply distinct, one from the other, the nuclei are well filled out. 

 When however the border line is disappearing, the ovarian nuclei 

 collapse, frequently disappear entirely, and rows of granules appear, 

 running from the ovarian cell body up into the egg. A chemical 

 influence must be exerted upon the ovarian cells which furnish from 

 their cell substance the granules that stain with the osmic acid 

 and which are taken up by the egg by its active protoplasmic 

 movement (p. 288)." 



The second type of procedure in the appropriation of the 

 interstitial cells occurs when the latter have completely transformed 

 the nutritive matter they have received into yolk substance. This 

 process may be described briefly, thus: A pseudopodium, or other 

 portion of the egg, comes into contact with the interstitial cell; 

 gradually, through some influence likely ascribable to the egg, the 

 protoplasm of the interstitial cell assumes the appearance of the 

 egg cell (Fig. 7. Plate 11). The cell wall separating egg and 

 interstitial cells is then absorbed and the cytoplasm of the two 

 becomes confluent. The nucleus of the interstitial is transferred to 

 the center of the egg mass and so becomes a pseudocell (Fig. 6, 

 Plate 11). AVhen a nutritive cell is mature, so to speak, it is 

 ingested entire by the egg and its nucleus becomes a pseudocell: 

 when the nutritive cell is immature it suflers disintegration and 

 then is absorbed by the egg which utilizes the material after it has 

 further elaborated it, to make other pseudocells. I do not believe 

 that Tanneeuther correctly interprets appearances when he ascribes 

 an amitotic division to the pseudocells; it seems more probable, in 

 the light of the earlier observations already referred to. tliat he 

 has seen stages in the fusion. I shall later show, too, that the 

 pseudocells are of a nature to preclude such active division. 



19. The yolk bodies or pseudocells are granules of lecithin 



