NUCLEOLAR EXTRUSION 139 



Nath (93) describe in the oogenesis of Lithobius forficatus two 

 phases of nucleolar extrusions. The first are budded off and 

 extruded (King), and give rise to secondary nuclei (Nath). King 

 does not trace their fate ; Nath says they disappear. The second 

 phase of nucleolar activity differs from the first in that the nucleo- 

 lus itself fragments, and is apparently totally extruded. King 

 says they grow into yolk spheres, while Nath states that they 

 disappear before the appearance of vitelline (albuminous ?) yolk, 

 but thinks they may have something to do with it. (The two 

 researches were carried on independently and practically simul- 

 taneously.) 



Spaul (117) attributes the formation of yolk to the nucleolar 

 extrusions in Nepa. Harvey (46), in Carcinus moenas, also states 

 that nucleolar extrusions are associated with the yolk droplets. 

 Nath, in scorpions (96), describes basophil and oxyphil extrusions. 

 These disappear later as the albuminous yolk becomes prominent. 

 He does not trace any direct transformation from nucleolar extru- 

 sions into yolk droplets. The same author has stated that the 

 basophil bodies lying in the acidophil nucleolus of the oocyte of 

 Luciola gorhami (101) breaks up, migrates into the cytoplasm, and 

 gives rise directly to albuminous yolk. The nucleolar budding in 

 this case lasts throughout oogenesis. He also finds, however, that 

 there are no extrusions in the spider Crossoproza lyoni (99), although 

 there is albuminous yolk and in the centipede Otostigmus Fece (100) 

 only a few extrusions take place, which disappear long before the 

 albuminous yolk puts in its appearance. Nath and Mohan, in 

 Periplaneta, describe the albuminous yolk as nucleolar in origin, 

 the extrusions moving to the periphery of the cytoplasm and then 

 breaking up into small bodies evenly distributed. They subse- 

 quently grow enormously in size. Gatenby finds, in Sycon com- 

 pressa, nucleolar extrusions in oogenesis, but is unable to assign 

 any definite function to them (32). King, in Peripatopsis capensis, 

 notes nucleolar budding in very young oocytes. These have, 

 however, only been traced as far as the nuclear membrane (70). 

 Hirschler, of course, attributed a nucleolar connection to the yolk 

 nucleus in Ciona intestinalis (49), and Harvey, although he states 

 the yolk nucleus to be formed by the Golgi apparatus, conceives the 



