BIOLOGY OF PARACOPIDOSOMOPSIS. 4! 



The growth stage is characterized by the presence of a con- 

 spicuous nucleolus, which occupies an excentric position in the 

 nucleus (Figs. 2-4). At first the nucleolus is somewhat diffuse, 

 but later its outline becomes sharp and distinct (Fig. 2). It 

 frequently has several less deeply stained areas lying at its 

 center (Fig. 3). We have good reasons for believing that the 

 nucleolus is chromatin in character. 



One of the most striking changes to occur in the cell during 

 growth, is the appearance of certain cytoplasmic inclusions, 

 which stain intensely black with iron haematoxylin. These are 

 first seen about seventy- two hours after pupation, when they 

 appear as dark, elongated areas in the cytoplasm. Later, as the 

 cell enlarges, the areas become more definite and appear as seen 

 in Fig. 3. These structures soon disappear (Figs. 4, 5), although 

 some of them may persist until after the first maturation division 

 is well advanced (Figs. 6, 8). We have not attempted to deter- 

 mine the origin and nature of these cytoplasmic inclusions; but, 

 judging from the work of Meves on the bee, they are probably 

 mitochondrial in character. 



The presence of these inclusions greatly interferes with the 

 study of the changes which now take place in the cell. Especially 

 is this true with reference to those changes involving the behavior 

 of the centrosomes. We shall therefore confine our account to 

 the changes in shape of the cell which occur during the growth 

 period. As already stated, all of the cells of a cyst are at first 

 united at their pointed ends by the interzonal connections. In 

 some cells these connections are soon lost, and each cell then 

 becomes polyhedral in outline (Figs. 2, 3), and finally spherical. 

 In other cells the interzonal connections apparently persist 

 throughout the entire growth period, and after these are finally 

 severed, the pointed end of each primary spermatocyte contains 

 the remains of the original interzonal connection in the form of 

 an "interzonal body" (Mark and Copeland). 



At the end of the growth period many cells are met with 

 which possess a delicate process. It is difficult to demonstrate 

 the presence of a centrosome at the end of this process (Fig. 4). 

 With reference to the position of the cell in the cyst, the process 

 may lie on any side of the cell. It is not clear whether such a 



