§> 242. THE CEPHALOPODA. 27^ 



dian line of the body until it reaches the base of the large fin-muscles, situ- 

 ated at the extremity of the body.'-"'' 



With Nautilus, numerous filaments arise from the posterior ganglionic 

 band, and, without forming a ganglion, are distributed to the two muscles 

 of the shell. From their origin, they may be regarded as the representatives 

 of the pallial nerves of the other Cephalopoda.'"' 



Another pair of nerves corresponding to the Pneumogastric nerves of the 

 Vertebrata, arises from the middle of the inferior cerebral mass, between 

 the two pallial nerves, descends along the neck behind the funnel, the pos- 

 terior wall of which it pierces, and thence passes under the peritoneum ; 

 here it sends several nerves to the ink-sac, and then ramifies upon the hearty 

 the large vascular trunks, the branchial hearts, and the branchiae. Both 

 of these nerves have ganglia, here and there, in their net-works,"' and these 

 net-works communicate probably with the Plexus splanchnicus posterior. 



§ 242. 



The Splanchnic nervous system is particularly developed with the Ce- 

 phalopoda. It may be divided into an anterior and a posterior plexus.^^' 



The Plexus splanchnicus anterior consists of a Ganglion pharyngeum 

 inferius, situated under the oesophagus sending filaments forwards to the 

 parts of the mouth, and backwards to the oesophagas, and connecting 

 at the same time with the inferior cerebral mass by two commissures.*^' 



With the Loligina, there is, beside, opposite this ganglion, a Ganglion 

 pharyngeum superius, which, also, sends several filaments to the parts of the 

 mouth, gives off two filaments to the inferior oesophageal ganglion, and 

 appears to connect, likewise, with the superior cerebral mass.*^^ 



The Plexus splafichnicus posterior is characterized by a large Ganglimt 

 gastricuTn lying upon the stomach. From this, filaments pass off in difi'er- 

 ent dii-ections to the other viscera, and it receives two filaments of commu- 

 nication, which, after having arisen from the inferior pharyngeal ganglion^ 

 accompany the oesophagus through the oesophageal ring.*'*' 



5 DcUe Chiaje, loc. cit. Tav. XCV. (25) and CI. 232, c. (Sepia); Van Beneden, loc. cit. p. 18, PI. 



(30), {Loligo). The two parallel nerves which, with I. flg. i, h. PI. III. fig. 5, k. and PI. IV. r. {Argo- 



LoUgopsis, extend backwards along the inferior nauta) ; Ou;p?i, On the Nautilus, PI. VII. fig. 1, 



dorsal surface of the mantle belong also to this class No. 15, or, Isis, Taf. IV. 7, fig. 1, or Ann. d. Sc. 



of nerves. Grant (loc. cit. p. 21, PI. II. fig. 5, 6), Nat. PI. III. fig. 4, No. 16 (Nautilus) ; and De/le 



has compared them to the spinal marrow of Verte- Chiaje, loc. cit. Tav. XCV. (25), C. (31), and CII. 



brata. With Onychoteuthis, I have also seen the (29), (Loligo, Sepia, and Octopus). 



two nerves of the fins running along the internal 1 For the sympathetic nervous system see Brandf, 



surface of the mantle, while with i^oZiiTo, as Z)eZZe lieber die Mundmagennerveu der Evertebraten, 



Chiaje has indicated in his Tav. CI. (30), they af- loc. cit. p. 40. 



terwards pass into the muscular layer of the man- 2 Brandt, Mediz. Zool. II. p. 309, Taf. XXXII. 



tie and continue their course between it and the fig. 23, 3 ; Owen, Cyclop, loc. cit. fig. 2ä2{Sepia)^ 



skin, sending ofif filaments to the two muscles of the Van Beneden, loc. cit. p. 16, PI. II. fig. 6 (Argo- 



fins. nauta); DeUe Chiaje, loc. cit. Tav. XCV. C.-CII. 



Ö Owen, On the Nautilus, p. 38, PI. VII. fig. 1, (25, 29-31), (Loligo, Sepia, and Octopus). 



No. 13, or, Isis, p. 32, Taf. IV. 7, fig. 1, or, Ann. d. i Brandt, Owen, and Delle Chiaje, loc. cit. 



Sc. Nat. p. 137, PI. III. fig. 4, No. 13. (Sepia and Loligo). 



7 These two nerves, analogous to the Par t;ag-!/,m, i Van Beneden, loc. cit. PI. III. fig. l-£ artt 



have been observed by all the Anatomists of these PI. IV. (Argoriauta) ; Brandt, loc. cit. Taf. 



animals; see Cuujer Mem. p. 36, PI. I. fig. 4, u. XXXII. fig. 3, 20 ; and Delle Chiaje, loc. cit. 



(Octopus) ; Brandt, loc. cit. Tab. XXXII. fig. 3, Tav. C. (31), and CII. (29), (Sepia and Loligo). 

 g. and fig. 23, k. ; Owe7i, Cyclop, loc. cit. I. fig. 



