THE TANGANYIKA PROBLEM. 



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evidently functioned as a brood pouch. The buccal mass 

 is very much reduced in Tanganyicia, appearing only as 

 a slight dilation of the alimentary tube, and the tongue 

 and the teeth (Fig. 32) are both proportionately small, 

 the denticles having the characters represented in Fig. 3L 

 The nervous system (Fig. 31), the ganglia, their cords 



Fig. 32. — Semi diagram of the digestive 

 system of Tanganyicia rufofilosa. 



and connectives, are all arranged in the typical cerithoid 

 plan, just as in Typhobia or Cancellaria. But there 

 is in the brain of Tanganyicia a curious median lobe 

 situated between the cerebral ganglia and looking forward, 

 which I have never found elsewhere. Except for the 

 addition of the large rectal gland in the female Tanganyicia, 

 and the reduction of the buccal mass in both sexes, the 

 whole alimentary canal (Fig. 32) is built on precisely the 



