212 W. M. SMALLWOOD. 



places giving the appearance of a reticulum. With the accumu- 

 lation of the microsomes, the reticulate condition is obliterated 

 and the cytoplasm becomes a dense mass of microsomes. In 

 such young ova the achromatic substance of the nucleus takes a 

 plasma stain such as Orange G or Bordeaux red. The vacuola- 

 tion of the nucleolus has begun by this time, the vacuoles taking 

 the plasma stain. This vacuolation of the nucleolus is in agree- 

 ment with the many cases already described. The vacuolation 

 continues until the nucleolus disappears which occurs before 

 maturation. The growth, vacuolation and eventual disappearance 

 of the nucleolus is an event which takes place during the growth 

 of the egg, but is not synchronous with any definite phase of this 

 growth. 



The young ova thus described are found in the entoderm at 

 the base, the side of the polyp, or in the gonophore. About this 

 time the ova take their permanent position (Bunting) in the gono- 

 phore, i. e., in the ectoderm where they increase greatly in size. 

 This increase in size is largely a matter associated with the growth 

 of the individual microsomes into small spherules. We are led 

 to believe from this study that there are also many microsomes 

 added which likewise are changed into spherules. These spher- 

 ules are so numerous in the adult egg as to conceal the ultimate 

 structure of the cytoplasm. They take a dense stain but not 

 always a homogeneous one. During this gradual growth, the 

 staining reaction changes, a change which can be readily seen on 

 a slide where all stages are represented. A number of such were 

 studied where all of the material had received the same treatment 

 from fixation to and including staining. On such a slide the young 

 ova are so deeply stained as to conceal most of the details of struc- 

 ture while the large eggs show but a faint response to the stain. But 

 when the more mature eggs are once stained in iron haematoxylin, 

 it takes considerable time to differentiate them in the iron so ten- 

 aciously do they hold the stain. Under these conditions one may 

 see on the same slide young ova black and blue-black in color 

 while the older eggs are hardly stained at all. Between these 

 two extremes, there are all gradations. This change in color 

 reaction is evidently due to the transformation of the microsomes 

 into spherules. 



