Nucleoli during' the Oogenesis of the Dragon-fly. 211 



bodies take the cliromatin stains, there must be a transformation of 

 the oxyphile substance of the nucleolus into basiphile material. 



(JoLDscHMiDT (1905) iu actlve gland-cells and muscle-cells of 

 Ascaris has described cytoplasmic chromatin which, instead of being- 

 gathered into irregular masses as in the Nissl bodies of nerve cells, 

 is arranged in fibres or coarse reticula. In most instances, however, 

 this chromatin, which he calls the "('hromidialapparat", is not derived 

 from nucleolar material but represents nuclear chromatin which has 

 made its way into the cytoplasm. In fact, in many cases, the 

 chromatic fibres of the cytoplasm extend directly through the nuclear 

 membrane and ai-e continuous with the chromatic reticulum of the 

 nucleus. Since the chromatic apparatus is more highly developed in 

 active than in resting cells, Goldschmidt concludes that it must 

 fnnction in the metabolism of the cytoplasm. 



i). The Function of the Nucleolus. 



Many nucleoli possess contractile vacuoles, and have, therefore, 

 been considered as excretory organs: B AhBixm {iS64:) m Phalanghtm, 

 Helix and Vortex; Böhm (1888) in Fetromyson; HXckek (1893) in 

 Echinus. Others regard them as a reserve supply of chromatin. 

 Flemming (1882) looks upon them as nuclear organs for the for- 

 mation of chromatin; Rhumbler (1893), Lavdowsky (1894) and 

 Hacker (1895) regard them, not as organs, but simply as deposits 

 of chromatic material. 



Montgomery (1899), adhering as he does to the extra-nuclear 

 origin of the nucleoli, is of the opinion that they represent sub- 

 •stances taken in from the cell-body, which stand in some relation 

 to the nutrient processes of the nucleus. His best proof is the fact 

 that in tlie period of rapid growth the nucleoli are very large. 



7. Relation of the Nucleolus to Synapsis. 



Gl-enther (1904) is of the opinion that the massing of the 

 chromatin around the nucleolus in the growth of many eggs is com- 

 parable to the synapsis as it occurs in spermatogenesis. 



III. Material and Methods. 



The work was done upon the larvae of tiie two dragon-flies 

 mentioned in tlie introduction, Anax Junius and Flatliemis lydia. 

 These larvae are found in ponds and streams, and in this locality 



Zool. Jahii). XXIII. Abt. f. Aiiat. 14 



