278 THE CEPHALOPODA. ^ 241. 



back of the mantle.'^' With Sepia, this inferior portion has several swell- 

 ings ; from the two anterior of these, which are the largest, arise the nerves 

 of the arms; while the two lateral posterior send oflF the two optic nerves.'^' 

 With Nantihis, this same ])ortion is divided into an anterior and a pos- 

 terior transverse band,''' which may be compared, to a certain extent, to 

 the semi-circle of ganglia upon the inferior surface of the oesophagus with 

 certain Gasteropoda. 



§ 241. 



Among the Peripheric nerves, those of the arms and mantle should be 

 specially mentioned. 



The Brachial nerves enter into the axial canals of the arms at the base of 

 these last, and extend even to their extremity after intercommunicating, each, 

 by a transverse anastomosis with the two neighboring nerves."* In their 

 course through this canal, they give off numerous filaments to the muscular 

 substance of the arms and to the suckers. With the Octopoda, these nerves 

 are composed of two parallel cords, each one of which has, alternately right 

 and left, ganglionic enlargements.'-* 



The two Pallial nerves, which are easily seen from their size, pass, at 

 first, between the cervical muscles, and, having reached the internal sur- 

 face of the back of the mantle, terminate in two very large ganglia [Gan- 

 glion stellatinn) from the external border of which pass off numerous nerv- 

 ous filaments, which enter, ray-like, the fleshy portion of the mantle.® With 

 those Loligina, which have fins, the pallial nerves, before terminating in 

 the star-like ganglia, send off a large branch, which, at a short distance from 

 its origin, is joined by another large branch from the pallial ganglion, and 

 is then distributed to the muscles of the fin. '^* With the long-bodied spe- 

 cies of this family, this nerve pursues a long course by the side of the me- 



1 The nervous system of the Cephalopoda has 2 Van Beneden, loc. cit. p. 14, PI. IT. fig. 3-5, 

 been carefully described by Ciivier, Mem. p. 34, PI. III. fig. 4, and PI. IV. (Ars^onauta). I have 

 PI. I. fig. 4 (Octopus) ; Krandt, Mediz. Zool. p. found the same organization with Octopus, and 

 SOS, Ta.(. XXXll. fig. 2'i (Sepia) ; Owen, a.nd Fa- Tremoctopiis. In this last genus, the ganglia 

 lenciennes, loc. cit. (Naiiti/us) ; and by Fan Be- may, from their reddish color, be very clearly sepa- 

 neden, loc. cit. (Argonauta) ; see, moreover, the rated from the white nervous substance. Both the 

 figures given by Owen, of that of Sepia (On the smooth and the nodulated cords send off nerve-fila- 

 Nautilus, PI. VII. fig. 3, or Isis, 1835, Taf. IV. 7, ments, but with the last, they arise exclusively from 

 fig. 3, or in the Ann. d. Sc. Nat. XXVIII. PI. III. the ganglionic swellings. 



fig. 5, and Cyclop. I. p. 549, fig. 232), and those of I have been unable to decide if the smooth cords 



Loligo, Sepia, and Octopus, in Delle Chiaje, send off filaments only to the muscles, and the nod- 



Memor. &c. Tav. XCV. C.-CU., and Descriz. Tav. ulated ones to the suckers ; or if the first contain 



XXV. XXIX.-XXXI.* only motory fibres, and the second sensitive fibres. 



2 Brandt, loc. cit. I should add that in the axis of Hectocotylus 



3 Owen, On the Nautilus, p. 36, PI. VII. fig. 1, tremoctopodis I have also found a highly-devel- 

 or, Isis, 1835, p. 30, Taf. IV. 7, flg. 1, or, Ann. d. oped, nodulated trunk, the number of swellings of 

 Sc. Nat. XXVIII. p. 134, PI. III. fig. 4, and Fa- which corresjionded with that of the suckers. 

 lenciennes, loc. cit. p. 287, PI. VIII. fig. 2-4. 3 See the figures of Fan Beneden, Delle Chi- 



1 Cuvier, M^m. p. 36, PI. I. fig. 4, (Octopus); aje, Brandt, loc. cit., and of Ourn, in the Cyclop. 



/Je«e CAiaje, loc. cit. Tav. CII. (29), C. (31), (Oc- I. fig. 232 (Argonauta, Octopus, Lo/igo, and 



topus and Sepia) ; F'erussac, loc. cit. PI. V', fig. Sepia). 



1, and Fan Beneden, \oc. cit. p. 15, PI. II. fig. 2, 4 See the figures of Delle Chiaje, and Owen, 



and PI. IV. (Argonauta).] loc. cit. (Loligo and Sepia). 



* [ § 240, note 1.] See especially the e.\cellent point out the homologies of the Cephalopoda with 



illustrations of Milne Edwards, Kigne anim, loc. the MoUusca. — Ed. 



cit. PI. I'J. See, for a very detailed description t [ § 241, note 1.] See also the illustrations of 



of this system with Ommastrephes, Hancock Milne Edwards, Ki^gne animal, loc. cit. PI. I. fig. 



(Auu. Nat. Hist. X. 1852, p. 1), who has sought to 3, f. f. (Argonauta). — Ed. 



