8^ 



ends of the lateral lobes. The right visceral connective 

 comes in rather at an angle, the left being nearer the 

 median line. 



Lying almost above the right connective, a little 

 before it reaches the ganglion, and on the other side, a 

 little to the left of the connective, are small pigmented 

 bodies (6^. osp.), which sections show to be ganglia made 

 np of a cortex of ganglion cells with long processes passing 

 into the centre, and with the outer ends drawn out into 

 several fine fibres. From these osphradial ganglia, nerves 

 pass up through the connective tissue to the epithelium 

 directly above. Here they become connected with 

 numerous sense cells, forming the Osphradium. 



The nerves connecting these osphradial ganglia with 

 the visceral, pass into the cerebro-visceral connectives and 

 enter the ganglion with these nerves. 



Two conspicuous nerves arise from the visceral 

 ganglion close to the entrance of the cerebro-visceral 

 connectives, but slightly posterior to these. They arise, 

 also, at a slightly higher level than most of the nerves 

 which pass to the mantle. These are the branchial nerves 

 (fig. 28, iV. hr.) ; they pass out almost at right angles to 

 the cerebro-visceral connectives, and just passing below 

 the extremity of the renal organs, take up a position along 

 the outer margins of the latter, where they are easily seen, 

 beinar rather near the surface. This course is followed 

 until the expanded end of the afferent branchial vessel is 

 reached, when the nerves bend round and enter the 

 ctenidial axis, along which they pass, gradually becoming 

 more attenuated until the end of the lamellae is reached. 

 The nerve lies alongside and above the afferent branchial 

 vessel along its whole length (hg. 45, N . hr.), sometimes 

 nearer one side of the ctenidial axis than the other. 



This nerve is well supplied with ganglion cells, which 



