Fia. 123. 
Nervous system of 3 Streptoneurous Gastropods, showing the dialyneury and zygoneury, 
dorsal aspect. A, Paludina (after Bouvier, somewhat modified); Bb, Triton (after Haller); C, 
Lamellaria (after Bouvier). ab.g, abdominal ganglion; br.n, branchial nerve; ce.g, cerebral 
ganglion ; c.pe, cerebro-pedal connective ; c.pl, cerebro-pleural connective; di’, di’, left and 
right dialyneury ; 7.7.9, infra-intestinal ganglion ; ot, otocyst; pa.n, pallial nerve; pe.g, pedal 
ganglion ; pl.g, pleural ganglion ; pl.pe, pleuro-pedal connective ; s.7.g, Supra-intestinal ganglion ; 
st.g, stomato-gastric ganglion ; vi.c, visceral commissure ; vi.c’, vi.c’’, Supra-intestinal and infra- 
intestinal part of the visceral commissure ; zy’, zy’, left and right zygoneury. 
143 
