ON LIMNODRIIAJS GOTOI, N. SP. 7 



to these glands, and therefore it seems that they simply discharge their contents into 

 the perivisceral cavity. 



Nervous system. 



The brain lies ou the dorsal side of the mouth, iu the first segment. As seen 

 from the dorsal side it is almost square, with two protrusions at the posterior corners, 

 corresponding to the exit of the periesophageal commissures (fig. 7.) As shown in 

 the figure, two nerves are given off from its anterior corners and a third oue in the 

 median line between the two lateral. These three nerves ramify greatly in the 

 prostomium. The pericesophageal commissures are given off at the posterior pro- 

 trusions, and they unite on the ventral median line directly under the oesophagus. 

 The ventral ganglia lie one in each segment, except the anal, and are situated always 

 close to the posterior end of the segments. 



Alimentary system. 



The alimentary system is very simple as in other tubificid Limicohe, and presents 

 no peculiarity. The mouth lies on the ventral side of segment I ; the pharynx in 

 segments II and III ; its inner cavity is very capacious and concave ventrally. The 

 œsophagus is a narrow tube and occupies segment IV only. After this the canal is 

 swollen slightly, due to the presence of chloragogen cells, and forms the intestine, 

 which runs through the remainder of the body. The inner wall of the intestine con- 

 sists of ciliated columnar cells, but in the pharynx the cells are longer and stouter. 

 The nuclei are oval in all parts and occupy a basal position. The cilia near the anus 

 are very long and execute rapid vibrations. The chloragogen cells are pear-shaped 

 and ave much more numerous in the anterior than in the posterior portion, in which 

 they are also more elongated iu shape. The internal epithelium is followed by the 

 circular and longitudinal muscle layers, which are traversed by connective tissue 

 strands. 



Nephridia. 



The nephridia are present in segments VII — IX and XII to the last but one. 

 The funnel is attached to the anterior face of the septum, and the external orifice lies 

 just in front of the ventral seta-bundle. The mouth of the funnel is obliquely turned 

 towards the median line and its margin is thickly covered with long cilia, which 

 vibrate regularly in turn so as to make a wave pass from one end to the other. The 

 cilia growing in the lumen of the canal are short and their motion is very rapid. The 

 funnel is continued to a long narrow canal, which after undergoing manifold convola- 



