16 



E. NOMUIiA : 



et 



■■:■;■ , >' 



go 



cells. The ducts are never united to form bundles, as in Limnodrilus 

 willeyi. 



The endodermal cells of the pharynx in the region of the 

 gland openings are tall and cylindrical, and the nuclei which are 

 situated near the free surface of the cells are not nucleolated and 

 invariably pear-shaped, with the obtuse end turned outwards. 



The oesophagus is confined to segment IV. Its lumen is flattened 

 dorso-ventrally and is semicircular in cross section. As seen from 



the dorsal side the oesophagus is conical 

 in form, with its narrow end directed 

 posteriorly. In well narcotised specimens 

 it is not distinguishable from the phar- 

 ynx, but in contracted ones it is simply 

 flattened dorso-ventrally and nowhere 

 presents a semicircular shape in cross 

 section, in contrast to the pharynx which 

 presents a semicircular or pentaradiate 

 lumen. 



The intestine begins at the anterior 

 end of segment V and always lies, for 

 the greater part of its length, on the left 

 side of the body side by side with the 

 dorsal vessel, which runs through the 

 whole body length on the right side. Its lumen is nearly uniform 

 in calibre and irregularly shaped in cross section. The posteriormost 

 part of the intestine is slightly swollen into a bulb which directly 

 opens externally through the anus, a very small circular pore on 

 the dorsal side of the posterior end of the body. The endoderm 

 consists of ciliated columnar cells with the nuclei lying in the 

 middle. Outside this lies a well developed vascular layer which is 

 followed by feebly developed circular and longitudinal intestinal 



phr — 



n.phr 



Fig. 11. 

 Cross section through a phar- 

 yngeal gland. x700. ct — peri- 

 toneal connective tissue, gc — 

 pharyngeal gland cell, n.gc — 

 nucleus of gland cell, phr — 

 endodermal cell of the pharynx, 

 n.phr — nucleus of endodermal 

 cell, c — cilia. 



