No. I.] THE EGG OF LIMAX AGRESTIS. 205 



of the nucleus, or in regard to the relation of the aster to the 

 germinal vesicle. 



Sections through the hermaphrodite gland show many large 

 ovarian eggs which are still in contact with the walls of the 

 follicles, and in which the germinal vesicles are evidently in 

 various stages of breaking down. Even in the largest of these 

 ova the germinal vesicle still retains a distinct membrane 

 throughout the greater part of its circumference, and the large 

 nucleolus, which is characteristic of all of the earlier stages of 

 ovarian eggs, still persists. 



In none of these ova is there any radiate structure present, 

 or any evidence of the presence of a centrosome. The germi- 

 nal vesicle must be lost and the archiamphiaster formed after 

 the ovum becomes detached from the wall of the follicle ; but 

 as relatively few ovarian eggs reach maturity simultaneously 

 in Limax, the different steps in the process of ripening are 

 extremely difficult to find. Many of the younger ovarian eggs 

 are oval in outline, with a large surface of attachment to the 

 follicular wall. The structure of these ova is much denser 

 immediately around the germinal vesicle than at the periphery 

 of the cell. This dense region stains more deeply with haema- 

 toxylin than does the rest of the cytoplasm, and with Lyons 

 blue and borax-carmine it takes a deep blue stain. The 

 chromatin of the ovarian eggs also stains blue, as does likewise 

 the chromatin in the head of the spermatozoa that are still in the 

 follicles. These facts agree with Calkin's observations on the 

 color reactions of chromatin and yolk-nuclei in the ovarian q^^ 

 of Lumbricus. Beyond the fact that the chromatin and the 

 cell substance surrounding the nucleus stain alike, however, I 

 have no observations that indicate that the deeply dyed mass 

 around the nucleus has been derived from the chromatin. 



While the younger eggs are still oval in outline, the proto- 

 plasm is peculiarly stringy and irregular in appearance. Numer- 

 ous bodies which appear circular in section, and which stain 

 more deeply than the surrounding cytoplasm, are present at 

 opposite poles of the long axis of the %^^ ; there are also 

 numerous clear spaces in the cytoplasm which resemble vacu- 

 oles. What the significance of these structures is, I have not 



