IOO 



C. M. CHILD. 



connection with it and indicated diagramatically in the figure is 

 the oviduct. The outer portion of the female duct, i. e., that 

 leading from the region of the nephridial canals, is still in an 

 early stage of development and the genital opening has not yet 

 appeared. This sequence in the formation of parts is rather 

 peculiar ; the first portion to appear becomes the middle region 

 of the ducts while inner and outer terminal portions, including 

 the ovary appear considerably later. 



FIG. 4. 



In its earliest stages the ovary does not differ very widely in 

 appearance from the early stages of the ducts. It consists merely 

 of a number of nuclei in the parenchyma surrounded by more or 

 less cytoplasm and undergoing frequent amitotic divisions. But 

 the divisions seem to be somewhat less frequent here than in the 

 regions of the ducts and the nuclei never become so reduced in 

 size. But one difference between the ovary and the early stages 

 of duct-formation exists : viz., the occasional occurrence of a case 

 of mitosis in the ovary. Fig. 5 illustrates very clearly the occur- 

 rence side by side of the two forms of division. It represents a 

 portion of a longitudinal section through the inner end of the 

 oviduct and the ovarian region. The smaller cells (od~} on the 

 left in the upper part of the figure with elongated cytoplasmic 

 areas represent the terminal portions of the oviduct and the 

 region between these and the muscles, which are represented by 

 small circles, the ovarian region. In this section only a few of 

 the cells involved in the formation of the ovary appear ; they are 



