298 ALLEX. [VOL. I. 



in the number or location of the primitive cells which finally 

 become ova, although by far the greater number lie next the 

 manubrium, and few, if any, develop on the outer surface of 

 the germinal mass. I am inclined to agree with Doflein ('96), 

 p. 65, that all of the cells of the germinal tissue have potentially 

 the capacity of becoming eggs, but that those favored by better 

 nourishment or advantage of position are the first to develop. 



He says in this connection : " Das starke Wachsthum des 

 Gonophors hat einzelne Liicken und Spalten im Gewebe ent- 

 stehen lassen, und in diese wachsen nun die Keimgewebezellen 

 mit ihren Fortsatzen hinein." But while in my investigations 

 many such cracks were found, in most instances the pseudo- 

 podia extended between eggs where no crack occurred, and in 

 the greater number of ova no pseudopodia were present at all. 

 I am, therefore, led to the belief that proximity to cracks in 

 the germinal tissue is not of controlling importance, although 

 the eggs do undoubtedly take advantage of the room afforded 

 by such cracks when present. Doflein ('96) also states that in 

 Tubularia the growing eggs are always found next the manu- 

 brium or upon the outside of the germinal mass, unless cracks 

 are present within the tissue. I have examined a large number 

 of sections, and I find that in Parypha the eggs of the outer 

 layer are the last to develop, but that those in the interior of 

 the germinal tissue are often found considerably enlarged even 

 in the younger gonophores. 



When the growing cells have attained a diameter about three 

 or four times that of the cells of the germinal tissue, the 

 nucleus is found lying close to the periphery of the egg and is 

 oval and transparent, the chromatin fibers being scarcely vis- 

 ible (PL II, Figs. 5, 6). The nucleolus takes a fainter stain, 

 and in most cases contains a number of the refractile bodies 

 already mentioned. Later these bodies apparently unite, as 

 nearly the whole nucleus is often occupied by a single large 

 one. Just what their character is I am unable to state, but 

 they appear to contain oil, and certainly they are associated 

 with the peculiar metabolism exhibited by the cell at this time 

 (PL II, Figs. 5-7). In some of the eggs in which the nucleus 

 had this peripheral position, its outline was irregular upon the 



