1892.] 



FROM ALGERIA AND TUNISIA. 



33 



The epithelial lining of the (esophagus 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 

 })uts this into communication with the intestine which commences 



in the xvith segment. 



In the terminal dilatation of the oesophagus, the epithelium 



Anterior segments of Microscolex poultoni from the ventral surface. 



The segments are numbered consecutively, those of the cliteUum in Eoman 

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

 segments the nephridiopores are shown in front of the dorsal seta;. The 

 oviducal 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 xvtli segment; in Iruut of 

 Troc. Zool. Soc— 1S92, No. III. 3 



