^,22 MAINE AGRICUI^TURAIv i:XP]SRIMENT STATION. 1912. 



present. The epithelium covering these ridges is thrown into a 

 large number of secondary folds. 



In figure 474, two of the secondary folds from the epithelium 

 of the vagina are shown under higher magnification. From 

 this figure we note : 



1. The entire absence of any structures resembling the 

 tubular glands. The space beneath the epithelium is occupied 

 by connective tissue (cf. fig. 473). 



2. As in other parts of the oviduct, excepting the funnel, 

 two kinds of cells occur in the epithelium, viz : the ciliated cells 

 and the unicellular glands. 



3. Both kinds of cells are very much narrower and especially 

 over the crests of the folds they are longer than in many other 

 regions of the oviduct. 



4. In the depressions between the folds the cells are shorter 

 than elsewhere. At the bottom of these depressions there fre- 

 quently appears to be an accumulation of gland cells. No evi- 

 dence is at hand to show that these differ physiologically from 

 the other gland cells in this region. 



The appearance of the unicellular glands in this region, es- 

 pecially the narrowness of the cells, indicates that possibly they 

 serve a different function than the similar cells in other parts 

 of the oviduct. 



The function usually ascribed to the vagina is the production 

 of the outer shell cuticle and a portion, at least, of the coloring 

 matter of the shell. If this assumption is correct these sub- 

 stances must be formed by the unicellular glands described 

 above. 



It should also be stated that the walls of the cloaca contain 

 glands. Whether these are concerned with the production of 

 any egg substance or not has not been ascertained. 



Discussion, 



It may not be out of place to discuss very briefly the possible 

 significance of certain structures which have been described in 

 the fowl's oviduct. It must be remembered, however, that any 

 deduction drawn from the morphology of these structures must 

 be checked and possibly corrected by physiological studies. 



As noted on page 404 previous students of oviduct histology 

 have failed to find evidence of sflandular structures in the funnel 



