No. 2.] THE OVARIAN EGG OF LIMULUS. 165 



Balbiani's explanation of an extruded body in eggs of 

 Geophilus, as being a tube, would lose much of its incredible 

 features if the term tube had not been applied to it. The 

 observations themselves are no doubt correct, but his figures 

 are as diagrammatic as his language is colored by a vivid 

 imagination. 



Space will not permit an extended consideration of the many 

 problems concerning the nature and function of the nucleolus. 

 Most of them are well known, and the bearings of these 

 observations will be readily perceived. I would refer the 

 reader to the following authors : Cramer ('48), Ludwig ('74), 

 V. Wittich ('49), Leuckart ('53), Pfltiger ('63), Will ('86), Rhumbler 

 ('93), Balbiani ('83), Aime Schneider ('75), Valentin Hacker ('95), 

 Gegenbaur ('6l), Stuhlmann ('86), Bumpus ('9i), VValdeyer ('88), 

 Leydig ('55), Brandt ('78), Korschelt ('89), La Valette St. George 

 ('66), Gustav Mann ('93), McFarlane ('92), Goette ('75), Balfour 

 <'78), Henking ('82), O. Hertwig ('77, '92), Flemming ('75), Auer- 

 bach ('74), R. Zacharias ('87), Scharff ('88), Mertens ('93), Klein 

 ('78), Holl (-93), Jordan ('93), G. R. Wagener ('79), Platner ('86), 

 Wielowiejski ('85). 



Connection of the Egg with the Ovarian Tube. 



Before the formation of the egg membrane the cytoplasm of 

 the egg is continuous with the cytoplasm of the epithelium of 

 the ovarian tube. At times the neck of the egg, by which it is 

 joined to the epithelium, is comparatively large, so that the 

 epithelium appears to lie in direct contact with the egg over a 

 considerable area ; and its cytoplasm appears continuous with 

 several of the epithelial cells. In most cases the neck of the 

 egg is constricted to a narrow bridge of fibrous protoplasm, 

 proceeding from the epithelial cells and continuing into the egg 

 body as a polar mitosome. This polar mitosome can often be 

 seen to be continuous with a modified layer of protoplasm sur- 

 rounding, the egg immediately under the investing tunic ; and 

 it can also be seen to spread out in a fan-shaped manner in that 

 part of the egg adjoining the stalk. In a few cases the parallel 

 fibers of which the mitosome is composed have been seen to 



