280 THE CEPHALOPODA. §$ 248, 244, 245. 
CHAPTER V. 
ORGANS OF SENSE. 
§ 243, 
The sense of Touch is well developed with the Cephalopoda, and is situ- 
ated in the whole cutaneous envelope, in the fringed labial membranes, and, 
especially, in the arms. Nautilus is particularly rich in tactile organs, 
which are situated on the head; and this animal has, beside the thirty-eight 
tentacular arms, two external, and two median, large, labial prolongations, 
placed about the mouth, the border of which has twelve small, curled 
filaments, whose internal structure quite resembles that of the arms. 
The nerves of the filaments of the two external of these prolongations 
have an origin common with those of the arms, arising, consequently, from 
the front border of the anterior cerebral band. Those of the filaments of 
the median prolongations arise from the same band (but nearer the median 
line), by two common roots which, before dividing, have a flat ganglion. 
This animal has, also, four other curled tentacles, which can be retracted in 
a sheath, two in front of, and two behind, the eyes. These tentacles receive 
a special tactile nerve, which has its origin by the side of the optic nerve. 
§ 244. 
With the Cephalopoda, the fleshy point of the tongue is undoubtedly a 
Gustatory organ. It is concealed in the anterior angle of the lower jaw, 
and its rounding surface is covered with numerous soft villosities, which very 
probably serve as gustatory papillae. 
§ 245. 
The Olfactory organs of the Cephalopoda are situated in the neighbor- 
hood of the eyes, and consist, each, of a cavity with tumid borders, or of 
a cutaneous fossa which has an opening, and, sometimes, at the bottom, a 
whitish papilla. The nerves of these organs arise from the optic ganglion 
of the cesophageal ring, near the optic nerves. At first, they are closely 
united with these last, enter the orbit with them, and extend along its poste- 
rior wall, thence to the olfactory papillae, to which they are distributed in a 
ray-like manner,” 
1 Touch appears the only sense developed with 
Hectocotylus. If Costa’s figure (Ann. d. Sc. Nat. 
XVJ. Pl. XIII. fig. 2, e. f.) is exact, Hectocoty- 
lus argonautae has a special tentacle-like tactile 
organ on the anterior extremity of the body. 
2 Owen, On the Nautilus, P}. IV. Pl. VII. fig. 1, 
or Isis, 1835, Taf. IIL. IV., or Ann. d. Sc. Nat. 
XXVIII. Pl. IL. fig. 1, Pl. IIL. fig. 4, 
3 Owen and Valenciennes, loc. cit. Pl. VIII. 
fig. 2, i. and Pl. IX. fig. 1, i. 
1 This organization appears to have eluded the 
observation of most naturalists. I have seen it 
very distinctly, not only with the Loligina, but also 
with the Octopoda. Owen (On the Nautilus, p. 23, 
Pl. VII. fig. 7, or, Isis, p. 20, Taf. II. or, Ann. d. 
Sc. Nat. p. 113, Pl. IV. fig. 7, and Cyclop. I. p. 
554, fig. 236,) and Valenciennes (loc. cit. p. 280, 
Pi. X. fig. 3,4,), only, have represented with Nau- 
tilus this part of the tongue as having all the char- 
acteristics of a gustatory organ. With Sepia, the 
soft papillae have already heen figured by Savigny 
(Descript. de Egypte, loc. cit. Pl. I. fig. 4, 6, and 
in Férussac, loc. cit. Sepia, Pl. TY. fig. 22, 33). 
1 The cavities here mentioned were for a long 
time regarded as the external auditory passages, 
and the cutaneous folds surrounding them as a Pa- 
vilion (Férussac, loc. cit.), until Kelliker (Fro- 
riep’s neve Notiz. XXVI. 1843, p. 166, and, Ent- 
wickel. d. Cephalopoden, p. 107) discovered a 
special nerve, and declared, with reason, that the 
whole was an olfactory organ. The Cephalopoda 
being poor in vibratile organs, it is quite desirable 
to ascertain if these olfactory organs are ciliated, 
for they are so in fishes with which ciliated epithe- 
lium is likewise feebly developed. 
