The Non-Marine Mollusca of Portuguese East Africa. 



133 



surrounds the oesophagus, salivary ducts, and buccal retractor, being too 

 narrow to allow the buccal mass to be retracted through it. The cerebral 

 ganglia are united by a thick cerebral commissure, and each has a very 

 prominent lateral accessory lobe. The right cerebral ganglion gives rise 

 to the large penial nerve, in addition to the usual paired nerves. The buccal 

 ganglia are rather obscurely bilobed. The cerebro-pedal and cerebro- 

 pleural connectives are short, being considerably shorter than the cerebro- 

 buccal connectives. The pedal ganglia bear the otocysts on their upper 



49 48 36 24 23 



12 II 



Text-fig. 7. — Ledoulxia mozambicensis (Pfr.), Lebombo ilountains. 



A. Representative teeth from the radula ; X 350. 



B. Roof of mantle-cavity seen from within, showing kidney, etc. (slightly diagram- 



matic) ; Xo. 



surfaces ; their ventral surfaces seem to be obscurely divided by slight 

 transverse grooves into about three segments, of which the anterior pair 

 is much the largest. The visceral loop is very asymmetrical, and its ganglia 

 are all distinct from one another, though closely aggregated. The ab- 

 dominal ganglion is obliquely elongated behind the large right parietal 

 ganglion. 



Digestive system. — The jaw measures about 1-5 mm. in length. It is 

 rather thin and practically smooth, with a large median projection. 



The radula (text-fig. 7, A) measures about 3-3 X 1-5 mm. when flattened 

 out. The central and lateral teeth are tricuspid, the central being slightly 

 smaller than the laterals. The endocones of the lateral teeth are not 

 very conspicuous, being rather narrow and attached laterally to the stout 



