502 RIOHAKD EVANS. 



v\.\\e, at tlie posterior end of the ovary, the oviducts ^ ])assiiig" 

 forwards from it. 



No essential difference could be made out between the 

 oviduct and the proximal part of the uteri by looking' at a 

 complete preparation; but when sections were examined a 

 most marked difference was immediately noticed; but there 

 seems to be no sharp line of demarcation between tlie two 

 parts (compare fig'. 50, ovid., with tig. 51, ut.). 



It is difficult to make out that tlie cells lining the oviducts 

 are columnar, because the cell outlines are not easily seen, 

 and the nuclei may take up any position whatever in the 

 cells; that is, they may be found at the base, in the middle, 

 or at the free end of the cell (fig. 50). Another feature 

 of the cell-lining ot the oviduct is the sharp and well- 

 defined limit which the cells present towards the lumen 

 of the duct, which is in no way narrower than that of the 

 proximal portions of the uteri. 



The cells which line the uteri are quite different in charac- 

 ter from those which line the oviducts. In those portions 

 where there are no embryos tliey are distinctly columnar, 

 with well-marked cell outlines, with nuclei invariably situated 

 at their base, with granular cytoplasm, and their free ends 

 rounded and separate from one another; the result being the 

 absence of a well-defined limit towards the cavity of the 

 duct. The cells lining the uteri, whether near the recep- 

 taculum seminis or towards the exterior, possess glandular 

 and secreting characters. 



Up to the present time such a difference as has been shown 

 to occur between the lining of the oviduct and that of the 

 uteri in Eoperipatus has been found only in Paraperipa- 

 tiis Novse-BritannifB, discovered and described by Dr. 

 Willey (17,18). 



The oviducts have thick walls, consisting of the same 



' Tlie term oviduct is restricted in the present account to that portion of 

 the genital duct which is situated between the ovary and the receptaculum 

 seminis; the term uterus being used to designate the portion of the genital 

 duct in which the embryos develop, and which is situated between the re- 

 ceptaculum seminis and the exterior. 



