LIST OF ILLUSTRATIONS. 



Nervous system of Spekia zonata, Fig. 41 

 Semi-diagram of Spekia, Fig. 42 

 Semi-diagram of Spekia, Fig. 43 

 Shells of Neothauma, Fig. 44 . 

 Nervous system of Neothauma, Fig. 45 

 Nervous system of Vivipara, Fig. 46 



Diagram of molluscs 

 Diagram of molluscs 



CHAPTER XI 



CHAPTER XII 



Limnothelphusa metadata, Fig. 1 

 Platythelphusa armata, Fig. 2 

 Limnocaridina tanganyikiie, Fig. 3 . 

 Palaemon moorei, Fig. 4 . 



Arachnoidia? ray lankesteri 



CHAPTER XIII 



CHAPTER XIV 



Living Tanganyika medusa 



„ „ ,, , another 



Semi-diagram of medusa buds . 

 Young bud ..... 



„ , rather older . 



„ , still older 



CHAPTER XV 



Spongella moorei 

 Skeleton of Spongella moorei 

 Spongella tanganyikoz 

 Potamolepis veltneri 



CHAPTER XVII 



Pyrgulifera humerosa 

 Paramelania and purpurina 

 Nassopsis and purpurina. 



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