144 Transactions of the Society. 



nucleolen." These secondary nucleoli pass through the nuclear 

 membrane into the cell cytoplasm, and ultimately give rise to 

 chondriokontes or plasma rodlets. The latter appear to be true 

 mitochondria, and soon segment to form "secondary granules," 

 which swell up to form fat globules. The latter part of this 

 account agrees fully with the work of Murray and Dubreuil, but 

 the former part — i.e. that referring to the formation of the secondary 

 nucleoli and their passage into the cell cytoplasm — has not yet been 

 confirmed by other observers. We should like to know whether 

 the subcutaneous cells before their metamorphosis into fat cells 

 do not already contain mitochondria. 



It should be noted that Schreiner has used the latest cytological 

 methods, and for this reason alone his views demand attention. 

 (See p. 154.) 



The Archoplasm and the Formation of Yolk 

 FROM GoLGi Elements. 



In the undifferentiated cell, such as a spermatogonium or an 

 oogonium, the Golgi apparatus consists of a number of rods stuck 

 upon the surface of the archoplasm or condensed protoplasmic 

 substance surrounding the centrosome. 



In Limn^a or Helix (16) the Golgi apparatus, during oogenesis, 

 spreads out through the cytoplasm, its individual units increasing 

 greatly in number (PL II, fig. 5). During this process' it seems 

 probalDle that the original archoplasm becomes divided out among 

 the various Golgi elements or dictyosomes, so that finally each 

 little group of two to four or five Golgi rodlets reposes on a part 

 of the much-divided archoplasm. In Limnma this archoplasmic 

 substance can be traced back to the original archoplasm of the 

 oogonium. In the subsequent cleavage of the Qgg there comes a 

 time when the Golgi elements, hitherto scattered haphazardly in 

 the cytoplasm of the blastomeres, finally take up their position 

 near the nucleus, and in an excentric position. The archoplasm 

 of each daughter blastomere is therefore regenerated from a part 

 of the original archoplasm of the oogonium which gave rise to the 



egg {10)- 



But now when we turn to the oogenesis of Patella or an 

 ascidian we discover a further complication. In Patella and the 

 ascidians the Golgi apparatus is undoubtedly associated more or 

 less directly with deutoplasmagenesis. From the observations 

 we have made on the oogenesis of Patella it seems certain that 

 the Golgi elements are directly stuck upon the surface of spheres 

 whose chemical reactions are those of true yolk. 



We then enquire as to the fate of the archoplasm in these 

 cases. Do the yolk spheres represent the archoplasm loaded with 

 food substances, or has the original archoplasm degenerated or 



