78 



Transactions. 



The only really interesting feature about the system relates to the 

 character of the visceral loop, which is much longer in Amjjhihola than in 

 ordinary pulmonates. From the right and left pleural ganglia a connective 

 passes back to the visceral ganglion {gv), which is situated on the body- 

 wall below the oesophagus, slightl}^ to the right side. It is about the same 

 size as one of the pedal ganglia, and, as we shall see later, probably repre- 

 sents the fused infra-intestinal and abdominal ganglia. From it are given 

 off two strong nerves. The anterior one (k) runs out to the right side, 

 ventral to the common genital duct, and bifurcates, one branch running up 

 to supply the inferior pallial lobe, and the other backwards alongside the 

 rectum. The posterior nerve [1) is stout, and runs backwards to supply the 

 organs in the visceral spire. 



a 



Tig. 5. — The nervous system in situ ( X 4). a, first cephalic nerve ; d, fourth cephalic 

 nerve ; /, penial nerve ; g, nerve of genital duct and body-wall ; /;, nerve 

 to osphradial ganglion (which is represented in outline as it lies on the roof) ; 

 j, nerve to body- wall ; k, rectal nerve and its branch to the inferior pallial 

 lobe ; /, visceral nerves ; tn, n, nerves to body-wall ; cd, common genital 

 duct ; ce, cut edge of mantle ; gac, accessory ganglion ; cjos, osphradial 

 ganglion ; gsi, supra-intestinal ganglion ; gv, visceral ganglion ; i^e, penis ; 

 r, rectum ; t, tentacle. 



A short distance from the pleural ganglia the visceral commissure bears 

 two ganglia asymmetrically placed, the one on the right {gsi) being larger 

 and farther removed from the pleural ganglion than the one on the left {gac). 

 The right one may be termed the supra-intestinal, and from it are given off 

 two nerves. 



The osphradial nerve {h) runs outwards to the osphradial ganglion, which 

 is situated on the mantle on the right side. The osphradial ganglion 

 itself gives off small nerves to the osphradium and the mantle. A slender 

 nerve {j) supplies the body-wall. 



