1892.1 



FROM ALGERIA AND TUNISIA. 



33 



The epithelial lining of the cesophagus is folded ; this folding is 

 perhaps more marked in segments xi., xii., and xiii. In segment 

 XV. the oesophagus forms a globular dilatation, the walls of which 

 are perfectly smooth without any folding ; a very narrow aperture 

 puts this into communication with the intestine which commences 

 in the xvith segment. 



In the terminal dilatation of the oesophagus, the epithelium 



Fig. 1. 



Anterior segments of Microscolex poultoni from the ventral surface. 



The segments are numbered consecutively, those of the clitellum in Roman 

 numerals, the others in Arabic numerals. On the anterior thirteen 

 segments the nephridiopores are shown in front of the dorsal setaj. The 

 ovidueal pores are on segment xiv., the male pores on segment xvii. 



gradually gets higher until its cells are identical in appearance with 

 the tall narrow columnar cells which form the lining membrane of 

 the intestine. Just at the opening of the oesophagus into the in- 

 testine, the cilia are very long and conspicuous ; but the oesophageal 

 epithelium is also ciliated throughout the xvth segment ; in Iront of 

 Proc. Zool. Soc— 1892, No. III. 3 



