178 



MUSEUM OF ANIMATED NATURE. 



[Cuttle-fishes. 



MOLLUSCA (HETEROGANGLIATA, Owen). 



On leaving the vertebrate series of animals and 

 entering upon the present, a few words may be 

 deemed requisite. 



The title Moliusca, (tivcn by Cuvier to the beins:* 

 included in this grand department of the animal 

 kinjnlom, conveys an allusion to tlie general softness 

 of their structure ; it has been exchanged by Pro- 

 fessor Owen for the term Heterogangliata, in refer- 

 ence to the irregular distribution of the nerves and 

 nervous ganelist a term now adopted by most phy- 

 siologists. This extensive section embraces the 

 slugs, the conchiferous and tunicate mollusks, and 

 the cuttle-fishes. 



In the heterogangliate animals there is neither 

 an articulated skeleton nor a vertebral column. 

 The nervous system consists of filaments given off 

 from ganglia or knots, disposed in different points, 

 one principal ganglion being situated on the oeso- 

 phagus, which it encircles with a nervous thread. 

 The want of symmetry in the distribution of the 

 ganglia or nervous centres is in accordance with 

 the absence of symmetry observable in the ex- 

 ternal configuration of these creatures, as well as 

 in the variable arrangements of the internal 

 organs. 



The circulation is always double, — in other words 

 there is a systemic as well as pulmonic or branchial 

 circulation ; this function is assisted by an aortic 

 ventricle, from which the blood is returned by 

 veins from the aijrating apparatus, which first con- 

 duct to an auricle. In the cephalopods or cuttle- 

 fishes, there is a pulmonic as well as aortic ventricle, 

 and the pulmonic ventricle is even divided into 

 two ; when there is more than one ventricle they 

 are not united, but are often at a distance from each 

 other, representing two distinct hearts. The blood 

 is of a white or pale bluish tint. With regard to 

 the senses, it may be observed that though they 

 appear to be endowed with that of smell, yet 

 no express organ has been detected. Perhaps, as 

 Cuvier remarks, the whole of the external skin 

 receives impressions from the odorous particles of 

 bodies, resembhng, as it does, apituitary membrane. 

 None are endowed with the sense of sight, with the 

 exception of some of the gasteropods, as snails, 

 slugs, &c. ; and the pteropods, as the clio, which 

 have eyes ; and also the cuttle-fishes, which have 

 not only large bright eyes, but organs of hearing, 

 and a brain enclosed in an osseous case. 



The heterogangliata almost invariably present a 

 development of the skin which covers the body, 

 and more or less resembles a mantle ; sometimes, 

 indeed, it is reduced to a simple disc ; sometimes it 

 meets, and uniting, envelopes the body as in a 

 sheath ; sometimes it is hollowed like a sac, and 

 occasionally diverges in the likeness of fins. 



Many of these animals are naked, — some, how- 

 ever, are housed in shells of varied form and colour. 



With regard to the digestive apparatus there is 

 great difference. Generally, however, there are 

 salivary glands, and always a liver of large size. 

 Many have secretions peculiar to themselves. 



11 at a little distance apart by minute but very nume- 



1 rous pillars, the whole forming that light and porous 



I structure known in the shops as cuttle-fish bone. 



' In theCalamary (Loligo)this gladius is a long horny 



jl substance somewhat resembling the head of a spear, 



|i and often two or three exist in the same cavity. In 



ii both cases the plate is analogous to the small lamina 



I found in the mantle of some slugs, and may be 



regarded as a rudimentary shell, the vestiges of a 



1 structure which we shall find developed in the 



argonaut and nautilus ; in which animals we find it 



assuming the form and use of a true shell, over 



which the mantle is more or less reflected, but in 



which the animals are housed ; and we may here 



add that from this circumstance the cephalopods 



are divided into naked and testaceous. 



In order, however, to understand more clearly the 

 general character of these strange creatures, let us 

 turn to our pictorial specimens, beginning with the 

 poulp, or polypus of the ancients. 



Octopus vulgaris, common on the southern coasts 

 of Europe, and found on our own shores. 



CLASS CEPHALOPODA (CUTTLE- 

 FISHES). 



The Cephalopods may be described as marine 

 animals, having the body surrounded by a mantle 

 in the form of a sac or purse, with a large head 

 crowned with eight or ten long flexible but powerful 

 appendages, always furnished with suckers on their 

 internal surface, by means of which they not only 

 creep along at the bottom of the sea, but grasp 

 their prey and force it into the mouth, which is 

 armed with a parrot-like beak. The branchial 



Eouch communicates with the surrounding medium 

 y a sort of funnel, which projects beyond the 

 edge of the mantle, and opens anteriorly, pointing 

 to the head. All are oviparous. 



It is in these creatures alone of the mollusks that 

 definite rudiments of an internal skeleton are to be 

 found. This is, it is true, in a cartilaginous con- 

 dition, but still it cannot be mistaken ; a large 

 cerebral cartilage encloses and protects a ganglion, 

 which may be regarded as a brain, gives attachment 

 to the muscles of the tentacula, encloses an au- 

 ditory apparatus, and supports the eyes. Other 

 cartilages occur in different parts composing the 

 rudiment of a spine. But this commencement of a 

 skeleton must not be confounded with a corneous 

 or a calcareous structure contained in a large cavity 

 within the dorsal portion of the mantle, and there 

 secreted by the sides of the chamber itself. In the 

 cuttle-fish (Sepia ofiicinalis) this dorsal plate of 

 gladius is calcareous, consisting of a multitude of 

 lamina;, not closely compacted together, but kept 



2506, 2507. 



-The Common Cuttle-fish, oe 



POLYPDS 



(Octopus vulgaris). Poulp or Preke. There is 

 something strange and uncouth in the aspect of 

 this creature ; its long flexible arms moving and 

 curling in all directions, and its large eyes, which 

 stare with a fixed gaze, rendering it even re- 

 pulsive. 



A cursory observer would predict it ferocious 

 and carnivorous ; it is indeed one of the tyrants of 

 the waters, making fishes and Crustacea its prey. 

 When crawling at the bottom of the water, the 

 globose body is elevated ; the arms or tentacula 

 are spread out, and supported by them it travels 

 along as they seem to bend beneath it. These arms 

 are eight in number, long, narrowing to a point, 

 and in the present species united at their base by a 

 thick web : each of these flexible but vigorous 

 arms is crowded with suckers along its inner aspect 

 to the number of two hundred and upwards. Woe 

 to the fish that is enfolded in their strenuous grasp. 

 Vain is resistance ; the suckers adhere with such 

 tenacity that they may be sooner wrenched off than 

 unfixed. Closer and closer to the mouth is the 

 victim brought, it is secured as in a vice, and the 

 work of demolition commences. In some species, 

 as we shall hereafter find, the efficacy of these 

 suckers for holding slippery prey is increased by 

 the addition of a hook, which act^ like a grappling 

 iron. 



If we look at the suckers of the cuttle fish, fig. 

 2508, we shall see that each consists of an adhesive 

 disc, composed of muscular membrane, with a thick 

 fleshy circumference, presenting when expanded a 

 number of radii, converging around the circular 

 orifice of an inner cavity ; in this cavity is a move- 

 able muscular piston, which, when the sucker is not 

 in action, appears level with the circular aperture ; 

 but which, when the disc is closely applied to any 

 object, is drawn strongly back, the cavity it filled 

 being now a large vacuum ; the whole is, in fact, 

 an air-pump of most precise and beautiful construc- 

 tion. When the animal releases its hold, it relaxes 

 the contractor muscles of the piston, which returning 

 fills the vacuum and the suction ceases. 



In our seas none of the cephalopods are large 

 enough to be formidable to man. In the hotter 

 latitudes, however, species of gigantic size have 

 twined their dreaded grasp round human victims 

 and dragged them to destruction. According to 

 Deny de Montford, Dens, a navigator, avowed that in 

 the African seas, while three of his men were em- 

 ployed during a calm in scraping the sides of his 

 vessel, they were attacked by a monster of this kind 

 which suddenly appeared, seized them in its arms, 

 and drew two of them under water in spite of every 

 effort to save them ; and that the thickness of one 

 of the creature's arms, which was cut off in the 

 contest, was at its base equal to that of a fore-yard, 

 whilst the suckers were of the size of ladles. The 

 man who was rescued died delirious during the 

 night. We read also of another crew who were 

 similarly attacked off the coast of Angola : a gi- 

 gantic cuttle-fish threw its arms across the vessel, 

 and was on the point of dragsing it down, when the 

 crew succeeded in cutting off its arms with swords 

 and hatchets. When theif danger was most immi- 

 nent they prayed to St. Thomas for aid, and in 

 gratitude for their deliverance dedicated on their 

 return home a picture representing their perilous 

 encounter to the saint in his chapel at St. Malo. 

 Pennant states that in the Indian seas, as a friend of 

 his long resident in the Indian Islands, and a dili- 

 gent observer of nature, assured him, the Indians 



affirm that cuttle-fish are often seen two fathoms 

 broad over their centre, with arms nine fathoms 

 long ; and that when they go out in boats they are 

 in dread of them, and never sail without an axe for 

 protection. Even on the shores of Sicily, Mr. 

 Swainson saw cuttle-fish taken, two of which would 

 be a good load, their arms being as thick as those 

 of a man. 



It was probably a species of octopus that Mr. 

 Beale encountered while searching for shells upon 

 the rocks of the Bonin Islands. He was much 

 astonished at seeing at his feet a most extraordinary- 

 looking animal crawling towards the surf, which it 

 had only just left. It was creeping on its eight 

 legs, which, from their soft and flexible nature, bent 

 considerably under the weight of its body ; so that 

 it was lilted by the efforts of its tentacula only a 

 small distance from the rocks. It appeared much 

 alarmed at seeing him, and made every effort to 

 escape. Mr. Beale endeavoured to stop it by press- 

 ing on one of his legs with his foot ; but although 

 he used considerable force for that purpose, its 

 strength was so great that it several times liberated 

 its member, in spite of all the efforts he could em- 

 ploy on the wet and slippery rocks. He then laid 

 hold of one of the tentacles with his hand, and held 

 it firmly, so that the limb appeared as if it would 

 be torn asunder by the united efforts of himself and 

 the creature. He then gave it a powerful jerk, 

 wishing to disengage it from the rocks to which it 

 clung so forcibly by its suckers. This effort it 

 effectually resisted ; but the moment after, the ap- 

 parently enraged animal lifted its head with its large 

 projecting eyes, and loosing its hold of the rocks, 

 suddenly sprang upon Mr. Beales arm, which he 

 had previously bared to the shoulder for the purpose 

 of thrusting it into holes in the rocks after shells, 

 and clung with its suckers to it with great power, 

 endeavouring to get its beak, which Mr. Beale could 

 now see between the roots of its arms, in a position 

 to bite. Mr. Beale declares that a sensation of 

 horror pervaded his whole frame when he found 

 that this monstrous animal had fixed itself so firmly 

 on his arm. He describes its cold slimy grasp as 

 extremely sickening, and he loudly called to the 

 captain, who was also searching for shells at some 

 distance, to come and release him from his disgust- 

 ing assailant. The captain quickly came, and 

 taking Mr. Beale down to the boat, during which 

 time the latter was employed in keeping the beak 

 of the cuttle away from his hand, quickly released 

 him by destroying his tormentor with the boat- 

 knife, when he disengaged it by portions at a time. 

 Mr. Beale states that this cephalopod must have 

 measured across its expanded arms about four feet, 

 whilst its body was not bigger than a large clenched 

 hand. It was the species called by the whalers 

 " rock-squid." (' Natural History and Fishery of tlie 

 Sperm Whale.') 



It has already been said that the mouth of the 

 cuttle-fish is placed in the centre of the space en- 

 closed by the arms ; it consists externally of a thick 

 circular lip around an orifice : beneath this lip, and 

 partially appearing through the orifice, is a beak 

 like that of a parrot, excepting that the short man- 

 dible is the uppermost ; these mandibles do not 

 cover bone, but their interior is filled with a fibrous 

 substance of great strength and solidity. In the 

 nautilus these mandibles are blunt, of a calcareous 

 texture, and calculated to crush the shells of mol- 

 lusks. The muscles in which the jaws nf the cuttle- 

 fish are imbedded, and by which they are worked 

 are extremely powerful. In the ordinary octopus 

 they are capable of stripping off the armour from 

 crabs and lobsters, and of cutting up the flesh of 

 fishes. Within the mandibles is a fleshy tongue in- 

 vested with a papillose membrane of delicate tex- 

 ture, and also armed with recurved horny papillae, 

 so that the tongue, by its vermiform action, is 

 easily enabled to transmit the food into the gullet, 

 which passes through a ring in the cranial cartilage, 

 dilates into a spacious crop with glandular walls, 

 whence a short canal leads to a strong muscular 

 gizzard lined with a leathery skin. In this gizzard 

 the food is ground to pulp. At the root of the 

 tonffue there are large salivary glands. 



We have previously alluded to the connection of 

 the siphon or funnel with the branchial chambers. 

 The branchiae are situated in a distinct chamber on 

 each side of the body, separated from the viscera 

 by a membranous partition : the branchia; are very 

 beautiful, consisting each of a single stem with 

 foliated appendages. (The nautilus has two fringed 

 stems in each lateral cavity.) These appendages, 

 which like the gills of fishes are exquisitely vas- 

 cular, are laved by the water admitted info each 

 chamber, through a valvular aperture, and drawn in 



