214 W. M. SMALLWOOD. 



loses a large amount of chromatin by direct migration into the 

 cytoplasm which is entirely independent of the chromatin dis- 

 charged during the formation of the polar bodies. The subse- 

 quent fate of this discharged chromatin has been studied with much 

 pains and it is the belief of the writer that it is something as fol- 

 lows : When the cytoplasm of the egg is examined after it has 

 been discharged from the gonophore there appear many areas 

 that are free from the characteristic granules of the surrounding 

 cytoplasm. These areas are usually round and contain small 

 particles that stain with Borax carmine or haematoxylin. They 

 look so' much like faintly staining nuclei that their appearance is 

 very confusing at first (Fig. 6). As segmentation progresses, 

 these areas tend to migrate to the periphery of the egg and are 

 occasionally so numerous that they form a nearly continuous row 

 around the embryo, Fig. 9. Eventually they are absorbed by 

 the cytoplasm. This explanation, then, traces the highly vacuo- 

 lated condition of the cytoplasm in Hydractinia directly to the 

 migration of chromatin from the nucleus before maturation be- 

 gins. A similar series of changes occurs in Pennaria but at a 

 different time. 



LOCALIZATION OF THE FORMATIVE STUFFS IN Hydractinia. 



The following extract indicates the extent of the previous de- 

 scription of the structure of the cytoplasm. " Sections of the 

 egg show deutoplasm spheres distributed throughout the proto- 

 plasm, with the exception of the outer rim which is composed 

 entirely of protoplasm" (Bunting, page 215). 



The cytoplasm exhibits a rather definite localization of the so- 

 called formative stuffs in the presence of a coarsely granular 

 crescentic area (picro-acetic fixation) located on the side of the 

 egg in which the nucleus lies the animal pole. The appearance 

 of these granules in Hydractinia is very similar to what Hargitt, 

 '06, p. 214, has found in Clava. In addition to these bodies there 

 are some minute bodies located around the periphery of the egg 

 in a narrow band which takes a deep blue stain (Borax carmine, 

 Lyons blue method). These particles do not stain readily and so 

 were overlooked by Bunting. By the regular haemotoxylin 

 methods they are usually indistinguishable from the other micro- 



