36 NILS HJ. ODHNER, STUDIES ON RECENT CHAM1DAE. 



the sides of the oesophagus. They give nerves to the anterior adductor and the 

 anterior labial palps, but not to the posterior ones; both pairs of palps are innerved 

 from the buccal ganglia. A distinct dorsal pallial nerve exists only on the right 

 cephalic ganglion. It describes a curve upwards, passes in front of the oesophagus 

 över to the left side, branches, on the one hand, forward to the back side of the 

 adductor and on the other backward on the left side of the oesophagus into the 

 liver mäss. A very weak vestigial pallial nerve also emerges from the left cerebral 

 ganglion, but it only reaches the oesophagus and then disappears. 



Buccal ganglia are very distinct. They are connected to the cerebral centra 

 by a very short nerve emerging immediately beneath the pedal connectives. The 

 buccal ganglia innervate both labial palps. They are connected by a thin sub-oeso- 

 phageal commissure which, in its median part, consists of anastomosing ganglious 

 cords. 



The pedal ganglia are coalesced almost quite to a centrum with only a slight 

 dorsal furrow; it innervates the foot. Statocysts, each containing one statolith, were 

 observed somewhat above the pedal ganglia. 



The cerebro-visceral connectives run nearer to the stomach than to the body 

 surface. Just in front of the pericard the connectives are joined by a transversal 

 commissure. 



The visceral ganglion sends nerves to the gill suspensors and to the frontal 

 and the inferior side of the adductor. 



The genital organs. They extend from the upper sides of the umbones 

 through the whole body on both sides of the stomach and the intestine into the 

 most inferior pouch of the visceral hump. They are formed by narrow, highly 

 branched tubes, somewhat widened at their ends. They are also situated on the 

 frontal side of the stomach, thus surrounding it completely. The tubuli are joined 

 distally to some larger ducts which debouch through the papilliform genital orifices 

 situated in front of and somewhat higher than the inferior funnels of the pericard. 

 At about this level the genital tubes börder on the liver, which they surround on 

 its outer and inner side and between the lobea of which they wind. The sexes are 

 separated. 



The nephridia (fig. 29). As usual these are situated between the pericardium 

 and the posterior adductor and are lengthened in a dorso-ventral direction. Both 

 reach to the same height above at the sides of the median rectum. At about their 

 upper end the pericardial tubes debouch into the wider exteriör sacs, on their post- 

 erior sides. Farther down the pericardial tubes are flattened between the outer 

 sacs and the adductor. Finally they widen to an ampulla-like dilatation with num- 

 erous though short projecting folds. The two opposite ampullae börder on each 

 other medially and penetrate forward between the outer sacs. Their ciliated oscular 

 tubes are rather short with strong dense cilia and smooth, not plicated walls. At a 

 point above and in front of the ciliated funnels a very narrow communication opens 

 between the outer sacs, and a short median lobe descends between the funnels. In 

 their distal parts, the pericardial tubes have weakly plicated walls throughout. The 



