GAMETOGENESIS OF SACCOOIRRUS 11 



unravelling the intricate story of the origin and nature of the 

 complicated granulations of the oocyte cytoplasm. After a 

 year's work, and the making of a large number of preparations, 

 I feel that this present account is the correct interpretation 

 of the oogenesis. The egg cytoplasm of Saccocirrus contains 

 four kinds of grains or formed bodies : (a) Golgi elements, 

 (h) mitochondria, (c) true yolk, (d) nucleolar extrusions or 

 plastin-deutoplasm. 



These can all be distinguished one from another by some 

 staining method, as described on p. 18. 



(a) The Nucleolus during Oogenesis. 



Both Hempelmann and Buchner noted the peculiar peri- 

 nuclear bodies drawn in PL 3, fig. 23, nl, and concluded that 

 they were in some way concerned with yolk-formation. Such 

 a marked process as that depicted in this figure is unknown in 

 any other animal ; the history of the formation of these 

 extraordinary attachments to the nuclear membrane is not 

 at all easy to make out, and it is only after a study of material 

 fixed in Champy-Kull and stained by Benda's crystal violet 

 and alizarin that a satisfactory conclusion can be reached. 



In Champy-Kull-Benda preparations the nucleolus stains 

 a very characteristic orange-brown shade, while the mito- 

 chondria and chromatin are in shades of violet ; true yolk 

 (derived from the Golgi apparatus) is stained by the OSO4 of the 

 Champy's fluid. Now in such preparations the nucleolus of 

 the young oocyte is found to be budding off small pieces, as 

 shown in PI. 3, figs. 24 and 25 ; these pieces appear to wander 

 to the periphery of the nucleus and to pass through, but to 

 remain plastered upon the outer surface of the membrane, 

 as in PI. 3, fig. 24, nl. 



Some considerable variation in the exact method of this 

 process is found : in certain cases the pieces broken from 

 the nucleolus are coarse and easily distinguishable, as in 

 PL 3, fig. 24, but in some other examples, of which fig. 25 

 is hardly typical, the broken-ofl' pieces are so small that they 

 are difficult to identify. 



