THE TANGANYIKA PROBLEM. 
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proceeded less in Spekia than in any of the forms which 
Haller figured 
The gill in S. zonata is very much like that of the genus 
Fig. 43. — Semi diagram of the anatomy of Spekia zonata. 
The mantle cavity has been opened from above, and the 
nerves are represented in black. Opposite st the stomach ; 
stn. the gill ; ftps/, s. the crystalline style. 
Tanganyicia. The leaves are similarly broad, low, and 
triangular, and their apices are prolonged into the same 
littorinoid finger-like processes. 
Such processes are figured by Haller in the gills of 
