No. 2.] THE OVARIAN EGG OF LIMULUS. 151 



At the proximal pole the egg membrane is often partially 

 or completely destroyed ; and a nucleated mass of proto- 

 plasm within the egg appears directly continuous with the 

 protoplasm of the cells lining the stalk (PI. XIV, Fig. 31). 



That these bodies in the egg are real nuclei there is no 

 reason to doubt. They differentiate very excellently with the 

 ordinary nuclear stains. Diluted Delafield's haematoxylin, 

 slightly acidulated, makes them prominent ; and they show the 

 differential green stain of the Biondi-Ehrlich triple mixture. 

 From material collected at New Haven, where the animals 

 were in their normal habitat, preparations showing these 

 nuclei were obtained by means of the double stain of Lyon's 

 blue and lithium-carmine, the nuclei alone taking the carmine 

 stain. 



The final result of this process of absorption, both where 

 nuclei are present and where these are not to be observed, 

 seems to be the removal of the entire substance of the egg. 

 The last traces that are to be observed are those of the 

 egg membrane, which appears to persist for some time after 

 its contents have been absorbed. 



The lymph spaces adjoining the ovary containing such eggs 

 are often seen to be crowded with granular cells resembling 

 very much the granular cells surrounding the egg. 



Strahl ('92) found that, in the mature follicles of Lacerta 

 agilis, when the animals are kept in confinement and separated 

 from the males, an atrophy takes place in the mature ovarian 

 egg. The first evidence of this is the disappearance of the 

 nucleus ; second, the segmentation of the yolk as in cleavage, 

 and finally the entrance of leucocytes. These at first appear 

 aggregated around the point where the nucleus was situated, 

 but later they distribute themselves throughout the cg%. 



The segmentation of the egg of the domestic fowl in an 

 unfertilized state has frequently been afifirmed, among others, 

 by Oellacher ('72). In these, as well as in the unfertilized 

 eggs of bony fishes, according to him, a division of the nu- 

 cleus and a real cleavage takes place. The same has been 

 described in the egg of the dove by Motta and Mayo. 



Born claims to have observed a cleavage of the unfertilized 



