§ 246. 281 
THE CEPHALOPODA. 
. With Nautilus, the two olfactory papillae are situated, directly beneath 
the eyes, in a cavity which is surmounted by a wart-like swelling. With 
the Octopoda, the olfactory organs are concealed, behind the eyes, in the an- 
gle of insertion of the mouth upon the occiput. With Argonauta, and 
Tremoctopus, they consist of two naked papillae; and with Octopus, and 
Eledone, of two membranous cavities. 
With the Loligina, these organs are situated behind and a little below 
‘the eyes, and consist of fossae having narrow apertures; but they are easily 
‘seen from the elongated or round cutaneous swelling with which they are 
surrounded. 
§ 246. 
The Auditory organs of the Cephalopoda are situated in the lower mid- 
dle portion of the cephalic cartilage, where they form two more or less 
large, round cavities, separated by a cartilaginous septum, and without 
any external communication.2 With the Octopoda, the internal walls of 
these cavities are smooth ;* but with the Loligina they have many tuber- 
cles or papillae, which are sometimes quite prominent.” This portion of 
these organs may best be compared to the osseous Labyrinthus of the Verte- 
brata. These cavities are filled with a liquid substance, and contain, also,: 
-each, a small pyriform sac — membranous labyrinth — adhering to the car- 
‘tilaginous labyrinth at the point where the auditory nerve enters it, and 
upon which this nerve is spread out. 
This sac contains a single, white, 
irregular otolite of a crystalline texture. 
2 Valenciennes (loc. cit. p. 290, Pl. VIII. fig. 
2, h. Pl. LX. fig. 1, h. x., and fig. 3) in 1841, 
and consequently before Kélliker, described these 
organs as olfactory with Wautilus. He found not 
only the nerve which goes to the olfactory papilla, 
but also an orifice at the base of this last, leading 
into a cavity lined with a mucous membrane which 
had two regular rows of folds. Owen (On the Ceph- 
-alopods with chambered shells, p. 11) has regarded 
-these papillae, which he appears to have complete- 
ly overlooked in his earlier memoir, as short hol- 
low tentacles. On the other hand, he regards as 
the olfactory organs a row of twenty membranous 
lamellae arranged longitudinally at the entrance of 
the mouth between the two internal labial prolon- 
gations (On the Nautilus, p. 41, Pl. IV. 1, Pl. 
VIL. fig. 1, g. fig. 2, or Isis, p. 34, Taf. III. IV., 
or Ann, d. Sc. Nat. p. 141, Pl. II. fig.1,1., Pl. IIL. 
fig. 4, g. fig. 6); but it would appear to me that 
these lamellae are tactile lobules, for they receive 
numerous nerve-filaments from the ganglia of the 
nerves of the internal labial prolongations (Qwen, 
loc. cit.). 
3 With Argonauta, and Tremoctopus, these ol- 
factory nerves have a ganglion lying on the optic 
nerve (Kélliker, Entwickel. d. Ceph. p. 168); this 
-was seen by Van Beneden (loc. cit. p. 18, Pl. I. 
fig. 5, 6, k.), but not explained. The olfactory 
-cavities of Octopus did not, indeed, escape the no- 
tice of Rapp (Naturwiss. Abhandl., von einer Ge- 
selilsch. in Wiirtemberg, 1826, p. 69), and of Dedie 
Chiaje (Descriz. &c. Tav. VI. fig. 1. k. and Tav. 
XVIII. fig. 1, y), but they did not in the least sus- 
pect their nature. 
4 According to Owen’s account accompanied 
with a figure (On the Nautilus, pl. VII. fig. 3, No. 9, 
or Isis, 1835, Taf. IV., or Ann. d. Sc. Nat. XXVIII. 
Pl. IIL. fig. 5, No. 9, and Cyclop. I. p. 549, fig. 
232, k), the olfactory nerves of Sepia and Loligo 
appear to arise from a special ganglion situated 
24* 
near the Ganglion opticum. The entrance, with 
its tumid borders, of the olfactory cavivies, has 
often been figured with the Loligina, by Férussac 
(loc. cit. Sepia, Pl. XVII. fig. 2. c. Pl. XVIII. fig. 
3, b. Pl. XXVII. fig. 1, 6; Loligo, Pl. XX. fig. 
7, Pl. XXIII. fig. 5, 17, Pl. XXIV. fig. 2,14; 
Sepioteuthis, Pl. VI. fig. 2, b.; Sepiola, Pl. ILI. 
fig. 5, 15 b.). 
1 It has already been seen (§ 245) that the olfac- 
tory organs of the Loligina have been taken by 
some naturalists for an external ear. 
A very remarkable organ—a flexuous canal 
lined with ciliated epithelium, has heen seen by 
Kélliker (Entwick. d. Ceph. p. 105, fig. 60-63), 
but, only with the embryos of Sepia and Lolizo; 
departing from the auditive vesicles, it ran in 
front without opening either upon the surface of 
the body, or into the cesophagus, so that it could 
have been neither an external auditory duct, nora 
Tuba Eustachii. 
2 See Scarpa, Anat. disquis. de auditu et olfac- 
tu, p. 3, Tab. IV. fig. 11(Octopus); Delle Chiaje, 
Descriz. &c. Tav. XIV. fig. 1, d.; and Van Bene- 
den, loc. cit. Pl. I. fig. 3 (Argonauta). 
3 See Brandt, Mediz. Zool. p. 309, Taf. XXXIL 
fig. 14; Wagner, Icon. zoot. Tab. XXIX. fig. 37— 
39; Owen, Cyclop. I. p 554, fig. 235, and Trans- 
act. of the Zool. Soc. II. Pl. XXI. fig. 17; and 
Delle Chiaje, Descriz. &c. I. p. 68, Tav. XII. fig. 
12, 21 (Sepia and Loligo). This last-mentioned 
author has compared some of these cartilaginous 
prominences to the Ossicula of the ear ; but to me 
they appear to represent rather the first traces of 
semicircular canals, which, with the embryos of 
fishes, appear to consist, likewise, of simple prom- 
inences on the internal surface of the auditive vesi- 
cle. 
4 These otolites are composed mostly of carbon- 
ate of lime, and vary considerably in their forms. 
With the Octopoda, they resemble, more or less, a 
