No. 2.] THE OVARIAN EGG OF LIMULUS. 153 



In the next stage the germinal vesicle shows a tendency to 

 become irregular, owing to the appearance on its surface of 

 numerous diverticula or pouches (PL XVI, Fig. 105 ; PL XIII, 

 Figs. I, 6-i ; PL XIV, Fig. 24). These are often of consider- 

 able size. They are, for the most part, spherical and remain 

 connected with the germinal vesicle by means of a narrow 

 neck or isthmus. The network and stainable granules of 

 the germinal vesicle extend into these, and they are fre- 

 quently observed to contain pale " Nebennucleoli " (PL XIII, 

 Figs. 7, 8). 



Very frequently there is an accumulation of stainable gran- 

 ules at one point near the periphery of the germinal vesicle, 

 and this is at times so prominent that it might be mistaken for 

 a second " Hauptnucleolus." It, however, lacks the definite 

 form of the " Hauptnucleolus," and consists of irregular bodies 

 of very different sizes that stain deeply. When this is formed 

 in the central part of the germinal vesicle, the strands of the 

 nuclear network appear to radiate from it as a center (PL XIII, 

 Fig. 10). Occasionally this is so marked that it assumes the 

 appearance of an aster. In some cases the granules are less 

 pronounced ; and it can then be seen to have all the features of 

 a centrosome and sphere — a deeply stainable central body, 

 surrounded by a clear zone, which in turn is again surrounded 

 by an outer ring, from which the larger strands of the nuclear 

 network radiate. A somewhat similar arrangement of the 

 nuclear network around the nucleolus is sometimes seen (PL 

 XIII, Figs. 4, 8, 11). It is especially pronounced in material 

 hardened in Flemming's fluid (PL XIII, Figs. 4, 8), but the 

 appearances are by no means confined to such material. The 

 chromatin network seems often to have a centralized arrange- 

 ment, and the center of radiation may coincide with the 

 nucleolus or be independent of it. When it is found near the 

 periphery of the nucleus, the wall of the latter often shows 

 an indentation in the form of an acute re-entrant angle at that 

 point (PL XIII, Fig. 15). In such cases, which are of frequent 

 occurrence, the principal strands of the network can be seen to 

 radiate from this point in a fan-shaped manner. It can be seen 

 that this point is connected with fibers proceeding directly from 



