468 



J. F. ILLINGWORTH, 



the outer posterior angle of the cerebral ganglion. Further back the 

 end of the ganglion is joined by the two great connectives to the 

 pleural and pedal ganglia, the cerebro-pleural, being on the outside. 

 The cerebro-pedal connective gives ofi" a small pedal nerve (P.n) from 

 near its middle, which goes down into the anterior edge of the foot. 



Just inside the cerebro-pedal connective is the nerve (N. C) to 

 the otocyst (Fig. 14), which arises from the cerebral ganglion. The 

 otocysts themselves are minute globular bodies resting against the 

 anterior end of the pedal chords (Fig, 1 ot) and appear to have no 

 connection with the ganglia on which they rest, but are innervated 

 from nerves arising from the cerebral ganglia. 



The labial gangha supply many nerves to the circumoral muscles, 

 and also supply connectives to the buccal ganglia, which lie above 

 the radular supports. From the anterior part of each labial ganglion 

 a nerve (Fig. N 1) is given oö" which branches into the muscles of the 

 superior lip. Then further back three nerves {2, 3, 4) arise from the 



inside of each labial ganglion. 



LB 



Cerx uw 



i > 2 rP -f^ 



> / J 'A 



which supply the circumoral 

 muscles from the sides, an- 

 astomosing near the edge 

 of the mouth. These three 

 nerves have been described 

 as protractor muscle nerves, 

 but I do not believe that 

 -~'-C.PL.c. they give any nerves to these 

 ^^^ muscles but pass directly to 

 the circumoral muscles be- 



Fig, N. Dissection showing the labial nerves, l^^» ^^^^^^ terminal branches 



i: eye, En eye nerve, Cer cerebral ganglion, Cer. C going intO the Ciliated fringe 



cerebral commissure, C. P. C cerebro-pedal connective, f fVi 1" T? Vi* rl +1 



a PI. C cerebro-pleural connective, H. W nerves to ^^ '^'^e lipS. ßeüma tüese 



head wall, L.B labio-biiccal connective, Z. C labial and arising from the inner 



connective, Mo mouth, N. W nerves to neck wall, , . j. £ i i i • i 



T. n nerve to tentacle. posterior part of each labial 



ganglion, the connective is 

 given off to the buccal ganglia of that side. Still farther two or three 

 nerves are sent from the end of each labial ganglion into the muscles 

 of the inferior lip. Their terminal branches unite with those from the 

 nerves coming in on the sides, thus forming a complete anastomosis 

 of the nerves around the mouth (Fig. N). Finally a small commissure 

 unites the labial ganglia at their posterior ends (X. c). This com- 

 missure is somewhat difficult to demonstrate in the tough tissue of 



