234 Egbert Thompson Young, 



cells from a "cytoblastema" as was maintained so long ago by the 

 first named authors. 



In such an early stage of development as is shown in Figs. 15 

 and 16, one sees lying in the meshes of the parenchyma network 

 irregular masses of coarsely granular cytoplasm, mmj. These masses, 

 which are small at first but soon increase in size averaging 15 to 

 20 micra in diameter and occasionally exceeding 30 micra, are not 

 restricted to any particular part of the larva but are scattered 

 indiscriminately thru it. They are mostly irregularly ovoid or 

 pyriform in shape. Furthermore, the granular protoplasm composing 

 them is not necessarily collected in definite masses at all points, 

 but may be distributed along the parenchyma strands as already 

 described in an early part of this article and as is figured in Fig. 15. 

 It occurs both where the cells are densely packed together and 

 where they are widely separated, but naturally the definite masses 

 are found only among the scattered cells. The source of this proto- 

 plasm is the pre-existent parenchyma strands. 



Soon after the formation of these definite protoplasmic masses, 

 the observer may note sometimes one, sometimes several, small, 

 deeply-staining granules scattered haphazard thru the mass. These 

 granules vary in size from those 1^2 micra in diameter to those so 

 minute as to be with difficulty discernible under 2850 diameters. 

 This difi'erence in size I consider due to difi'erences in development 

 of the different granules. Frequently one finds one larger and 

 several smaller granules, sometimes they are of approximately the 

 same size. With their growth in size they usually, tho not always, 

 surround themselves with a clear zone which increases in size as 

 the granules increase.^) They also vary greatly in shape, some 

 being round, others elliptical or irregular in outline, which differences 

 may to some extent, but not entirely, be due to the position of the 

 plane of section relative to the axes of the granules. Shortly 

 succeeding the formation of these granules, a nuclear membrane is 

 formed around them ; the newly formed nucleus, together with a small 

 mass of cytoplasm, becomes partly constricted from the parent mass — 

 the daughter cell has been formed. Similar daughter cells are then 

 formed from the parent mass, but all remain in sjaicytial union both 

 with this mass and with one another. 



1) This zone is clearly shown in the figures of TowER (1900), 

 PiNTNEE (1880) and Child (1904). Towee refers to it as the "hyaline" 

 part of the nucleus. 



