278 § 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 off the two optic nerves.” 
With Nautilus, this same portion 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 cesophagus with 
certain Gasteropoda. 
THE CEPHALOPODA. 
§ 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 stellatum) 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, ata 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- 
1The nervous system of the Cephalopoda has 
been carefully described by Cuvier, Mém. p. 34, 
PL I. fig. 4 (Octopus); Brandt, Mediz. Zool. p. 
308, Taf. XXXII. fig. 23 (Sepia) ; Owen, and Va- 
lenciennes, loc. cit. (Nautilus) ; and by Van Be- 
neden, loc. cit. (Argonauta)s see, moreover, the 
figures given by Owen, of that of Sepia (On the 
Nautilus, Pl. VII. fig. 3, or Isis, 1835, Taf. IV. 7, 
fig. 3, or in the Ann. d. Sc. Nat. XXVIII. Pl. TIT. 
fig. 5, and Cyclop. I. p. 549, fig. 232), and those of 
Loligo, Sepia, and Octopus, in Delle Chiaje, 
Memor. &c. Tav. XCV. C.-CII., and Descriz. Tav. 
XXYV. XXIX.-XXXIL* 
2 Brandt, loc. cit. 
8 Owen, On the Nautilus, p. 36, Pl. VU. fig. 1, 
or, Isis, 1835, p. 30, Taf. IV. 7, fig. 1, or, Ann. d. 
Sc. Nat. XXVIII. p. 134, Pl. II. fig. 4, and Va- 
lenciennes, loc. cit. p. 287, Pl. VIII. fig. 2-4. 
1 Cuvier, Mém. p. 36, Pl. I. fig. 4, (Octopus); 
Delle Chiaje, loc. cit. Tav. CII. (29), C. (81), (Oc- 
topus and Sepia); F'érussac, loc. cit. Pl. 15, fig. 
1, and Van Beneden, loc. cit. p. 15, Pl. I. fig. 2, 
and Pl. IV. (Argonauta).t 
* [§ 240, note 1.] See especially the excellent 
illustrations of Miine Edwards, Régne anim, loc. 
cit. Pl. Ib, See, for a very detailed description 
of this system with Ommastrephes, Hancock 
(Ann. Nat. Hist. X. 1852, p. 1), who has sought to 
2 Van Beneden, loc. cit. p. 14, Pl. II. fig. 3-5, 
Pl. IIL. fig. 4, and Pl. IV. (Argonauta). I have 
found the same organization .with Octopus, and 
Tremoctopus. In this last genus, the ganglia 
may, from their reddish color, be very clearly sepa- 
rated from the white nervous substance. Both the 
smooth and the nodulated cords send off nerve-fila~ 
ments, but with the last, they arise exclusively from 
the ganglionic swellings. 
I have been unable to decide if the smooth cords 
send off filaments only to the muscles, and the nod- 
ulated ones to the suckers ; or if the first contain 
only motory fibres, and the second sensitive fibres. 
Ishould add that in the axis of Hectocotylus 
tremoctopodis I have also found a highly-devel- 
oped, nodulated trunk, the number of swellings of 
which corresponded with that of the suckers, 
8 See the figures of Van Beneden, Delle Chi- 
aje, Brandt, loc. cit., and of Owen, in the Cyclop. 
I. fig. 232 (Argonauta, Octopus, Loligo, and 
Sepia). 
4 See the figures of Delle Chiaje, and Owen, 
loc. cit. (Loligo and Sepia). 
- point out the homologies of the Cephalopoda with 
the Mollusca. — Ep. , 
+ [§ 241, note 1.] See also the illustrations of 
Milne Edwards, Régne animal, loc. cit. Pl. I. fig. 
3, £. f. (Argonauta). — Ep. 
