MALE GERM CELL8 IN NOTONECTA 95 



precarious nature of the mitochondrial stain of Benda, only a 

 few clearly differentiated slides were obtained. The general tone 

 of both cytoplasm and karyoplasm is a pale lavender or rusty 

 red, the chromatin is a brick red and the mitochondria a deep 

 purple. In the drawings, the lavender is represented as a pale 

 grey, the brick red as a darker grey, and the purple mitochondria 

 as black and dark grey. The earliest stage of N. insulata ob- 

 tained is shown in figure 111; the chromatin is in compact masses 

 in the karyosphere, and the mitochondria are scattered through 

 the cytoplasm. A mass of mitochondria from which project 

 fibers, is attached to the nuclear wall. A slightly later stage is 

 shown in figure 112, where the karyosphere is breaking up, and 

 the nuclear plate of mitochondria has disappeared. From these 

 figures, it is evident that the mitochondria are of two distinct 

 kinds, fibers and spheres. The spheres occur chiefly around the 

 nuclear periphery, and frequently form a complete circle about it. 

 The fibers usually occur further out in the cytoplasm and tend 

 to aggregate in several dense clusters. The relation between the 

 fibers and the spheres is shown in figure 113; the spheres have a 

 curved rod at the periphery extending about half way around the 

 circumference, the rest of the sphere is less deeply staining. By 

 a gradual disappearance of this less dense substance, the sphere 

 is converted into a fiber, or rather, the fiber which was already in 

 the sphere becomes free. Whether the fibers always originate 

 in this way, it is impossible to say. In figure 114 is represented 

 a metaphase of the first division in side view. As the asters form, 

 the mitochondria become pushed away from their vicinity 

 although a few of the fibers take up a position along the astral 

 rays. In the division stages, the mitochondria are quite evenly 

 distributed through the cytoplasm between the mitotic figure 

 and the cell wall, though there is usually a clear area at the periph- 

 ery of the cell. The spheres and fibers are more intermingled 

 than during the growth stages. When the cell divides, the mito- 

 chondria are divided en masse, so that each daughter cell receives 

 approximately the same amount (fig. 115). There is no evi- 

 dence that individual fibers or spheres divide, except possibly in 

 the region of constriction. In the interkinesis the mitochondria 



