THE REPRODUCTIVE ORGANS 77 



in the uterus where they are broken into a 

 network by transverse and obHque folds. 



Microscopically, the free surface of the 

 membrane is covered by a layer of columnar 

 epithelial cells which, according to Dr. F. M. 

 Surface, are of two different kinds. Ciliated 

 columnar cells are intermixed with goblet- 

 cells in about equal proportion (Fig. 46). In 

 the first part of the infundibulum goblet-cells 

 are apparently absent, this region being lined 

 by ciliated cells only. The bulk of the thick- 

 ness of the mucous membrane is composed of 

 glands. According to Surface these are shallow 

 depressions in the infundibulum, are absent in 

 the vagina, and are few or absent in a narrow 

 area sharply separating the albumen-secreting 

 region from the isthmus. In the other parts 

 of the oviduct the glands are large and so 

 abundant as to be closely packed together. 

 Each gland is very long, tubular, and branched, 

 and lined by a granular epithelium. Before 

 secretion actually takes place the granules of 

 the epithelium are large ; but after the egg 

 has passed on its way towards the vagina 

 they are much finer. Tlie albumen of the egg 

 is secreted by the albumen region of the 

 oviduct ; the shell-membrane by the isthmus ; 



