44 HARLEY N. GOULD 



and these folds are supported by connective tissue ingrowths 

 frorn the surrounding sheath. The descendants of the high, 

 transparent cells which made up the wall of the duct at an 

 earlier period (fig. 78) have assumed a different character (fig. 

 82). They now form a cubical epithelium whose regularly dis- 

 posed cilia are shorter than those of the goniduct at all previous 

 stages. The proximal part of the duct, which was formerly the 

 seminal \iesicle, has not changed so markedly in appearance; it 

 is still composed of transparent columnar cells, though they are 

 now even more drawn out in length and have a clearer cyto- 

 plasm (fig. 84). The proximal part of the duct has not experi- 

 enced the same relative growth in diameter as the distal (cf. figs. 

 81 and 83 with figs. 77 and 79). 



From this point on, as the oocytes increase in size and in yolk 

 content, the folded cubical epithelium of the more distal part of 

 the oviduct is found nearer and nearer the ovary. The cells of 

 the proximal portion undergo at this time an unequal growth into 

 the lumen, nearly closing it up in places. A somewhat similar 

 process has been figured by Giese in C. unguiformis. 



Eventually the deep, transparent epithelium becomes limited 

 to the extreme proximal end of the oviduct where the latter is 

 connected with the ovary, and persists there when the animal 

 is in the adult female phase. The rest of the oviduct is then 

 composed of a cubical ciliated epithelium thrown into longitu- 

 dinal folds. 



The only further change in the oviduct, as the animal becomes 

 a functional female, is the appearance of unicellular glands in 

 its wall (fig. 85). They are first seen, here and there, in the 

 more distal part of the oviduct a little later than the stage of 

 figure 81. They become more and more numerous and are found 

 more proximally; in the adult female they are found in all the 

 folded epithelium of the oviduct. They contain a granular 

 secretion which stains a deep blue with Delafield's haemotoxy- 

 lin. Giese has described somewhat similar glands in C. ungui- 

 formis. In the case of the latter species they are more irregular 

 and their enlargement seems to result in the partial destruction 

 of the oviducal epithelium. Giese considers them pathologi- 



