44 



WRIGHT AND MACALLUM. ' [Vol. I. 



chromatin disposed in granules in the nuclear cavity. The 

 cytoplasma is also slightly granular, and either takes a feeble 

 stain in cochineal or none at all. These cells are quite distinct 

 from the structures in the fibrous membrane, and may be com- 

 pared to the parietal cells of the testicular lobules, for out of 

 them arise by increase in size and division, the cells filling the 

 cavity of the ovary. Such a division is represented in Fig. \%,b. 

 and a number of examples of the different stages of this divis- 

 ion can be made out in each ovary. One of the resulting two 

 cells falls into the cavity of the ovary and takes there, through 

 pressure of the adjacent cells, a wedge-shaped form. Owing to 

 the fact that the single ripe ovum is placed at one pole of the 

 ovary, while the newly formed ova are added at the other pole, 

 the intervening cells have their long axes parallel to each other 

 and directed transversely across the cavity of the oyary. Their 

 cytoplasma is granular, has a certain amount of staining ca- 

 pacity, and is limited peripherically by a thin membrane, on the 

 inner face of which is a layer of definitely placed granules, often 

 giving the impression of striation to the membrane. The nuclei 

 are oval, and vary in diameter from 12 ^iz to 60 ^, according to 

 the age and condition of ripeness of the ovum. The chromatin 

 is disposed either in nucleoli, which may measure as much as 

 8 /U in thickness, or in granules arranged in festoons throughout 

 the nuclear cavity. The nucleoli are spherical, contain a 

 vacuole, and, when they are of the size given, only one is to be 

 foun-d in each nucleus. 



The ripe ova measure about 55-60 ^, and their nuclei about 

 35-40 [I. The latter, in the fresh condition, are large, clear 

 structures, enclosing one or more nucleoli, which may or may 

 not have vacuoles in their interior, but in the fixed condition 

 there are found besides the same festoons of chromatin 

 granules exhibited in the unripe ova. The cell-substance, clear 

 and homogeneous in the fresh condition, in the fixed state is 

 seen to contain granules disposed in the meshes formed by 

 wavy fibrils of the cytoplasma. The cell-membrane is thick and 

 striated, the striations being due to delicate canals traversing it. 



With regard to the minute structure of the oviduct and the 

 other sexual ducts we do not find anything worthy of remark, 

 except the strong ciliation of the uterine tract of the oviduct, 

 the central part of the ootype and the overflow-tube. Unlike the 



