CLAVEL1NA. 151 



in a straight line as a wide equal tube, retaining its 

 diameter until it reaches the upper or cardiac end of 

 the stomach, when it suddenly contracts and becomes 

 united to that viscus. The stomach is rounded and 

 somewhat elongated, and is considerably wider than 

 the rest of the alimentary tube, hanging, as it were, 

 from the oesophagus towards the ventral wall of the 

 abdominal chamber. It is of a full yellow colour, with 

 firm Avails which are divided externally into three or 



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four longitudinal facets by as many pale, ridge-like 

 septse. The intestine leaves the lower end of the 

 stomach, and, dropping downwards, is almost imme- 

 diately constricted ; it then widens again, and on 

 approaching the bottom of the chamber once more 

 suddenly contracts, and then, as suddenly regaining- 

 its former calibre, turns towards the dorsal margin, 

 ascends on this side of the stomach, crosses on the 

 right of the oesophagus, and terminates in the anal 

 orifice within the base of the cloaca a little above the 

 level of the mouth. 



The alimentary tube does not lie free in the abdo- 

 minal chamber; but it is adherent to the wall appa- 

 rently by a fold of the lining membrane, the oesophagus, 

 stomach, and intestine being bound as it were in a 

 peritoneal sac. 



In this genus there is only one hepatic duct ; it is a 

 short, narrow tube, which passes from the intestine a 

 little above the loop, and carries the biliary secretion 

 into the dorsal side of the intestine immediately below 

 the stomach. The branches of the duct ramify over 

 the intestinal tube, dividing dichotomously, and ending 

 in comparatively-large oval vesicles, which are scat- 

 tered over the surface of the intestine from a little 

 above the loop to a short way in advance of the level 

 of the upper extremity of the stomach. 



The nervous system is not conspicuously developed. 

 A small ganglion can be observed in the usual situation 

 between the two respiratory tubes. The nerves have 

 not been traced. 



