178 



NATURAL HISTORY. 



collection, British Museum. Mr. Stiuchbury mentions that the Sandwich Islanders sold these 

 lustrous eyes to the Russians as pearls 



A remarkable organ with which some of the Cephalopoda are provided is a sac, popularly called 

 the '' ink-bag," in which is stored a deep black secretion, which they are able to employ at will as a 

 protection from rapacious enemies. On the approach of a suspected foe the animal discharges a 

 quantity of this dense fluid, which renders turbid the surrounding water, and thus enables its owner 

 to escape in the obscurity. There is a communication between this ink-bag and the funnel or 

 locomotor-tube, so characteristic of all the Cephalopoda, so that when the ink is ejected it is forcibly 

 emitted with the stream of water, which produces the rocket- like backward motion. The very effort 

 to escape thus serves the double purpose of propelling the creature away from the danger and 

 discolouring the water through which it moves. 



" The position of the ink-bag varies in different families. In the Octopus it is buried in the 

 substance of the liver, and this animal does not emit its ink so readily as the Cuttle or the Squid. 

 They very rarely do so in captivity, except when greatly exhausted or persistently irritated. It has 



been said that after being a few hours in captivity the Octopus loses the 

 power of secreting ink. There is no foundation at all for such a statement. 

 When placed in a tank especially reserved for it, in which are ho enemies 

 to cause it fear, it has no need to conceal itself, and therefore does not un- 

 necessarily eject its cloudy fluid." Mr. Lee states, "I have never dis- 

 sected an Octopus, no matter how long it might have lived in 

 confinement, without finding the ink-bag fairly charged, though some 

 of its contents are sometimes emitted when the animal is at the point of 

 death." 



" The Cuttle (Sepia) discharges its ink on the slightest provocation ; 

 and this is sometimes very troublesome and annoying when this species 

 is exhibited in an aquarium. The quantity of water its ink will 

 obscure is really surprising. The fluid is secreted with amazing rapidity, 

 and the black ejection frequently occurs several times in succession. I 

 have (says Mr. Lee) often seen a Cuttle completely spoil in a few 

 seconds all the water in a tank containing 1,000 gallons." 



When first taken, the Sepia is most sensitively timid. Its keen, 

 unwinking eye watches for and perceives the slightest movement of its 

 captor, and if even most cautiously looked at from above, its ink is 



belched forth in eddying volumes, rolling over and over like the smoke which follows the 

 discharge of a great gun from a ship's port, and mixes with marvellous rapidity with the water, 

 whilst the animal simultaneously recedes to the best shelter it can find. 



It is worthy of notice that the Pearly Nautilus and the allied fossil forms are without this 

 means of concealment, which their strong external shell renders unnecessary for their protection. 



" Fishermen are well acquainted with the fact that the Cephalopods at any rate, our British 

 representatives of the Sepiidw, Calamaries, and Octopoda habitually discharge, when taken, a jet of 

 black water, and the two former sometimes eject their ink in the faces of their captors. It has 

 been regarded as doubtful whether this is an intentional act or whether it is accidental, and conse- 

 quent on the bringing of the orifice of the siphon-tube above the surface, and the removal of the 

 resistance to the outpouring current which, when ejected under water, would in the one case 

 have been a means of locomotion, and in the other of concealment of their whereabouts. Some have 

 supposed that the emission is involuntary, and is produced much in the same way as the water is 

 tossed up in spray by the screw of a steam-vessel when her stern rises whilst she is pitching heavily 

 in a rough sea. Others who have experienced the effect of this habit of tlte animal's have persistently 

 asserted that they take deliberate aim, with the motive of aggression or self-defence. 



" The ' ink ' which the Cattle-fish has the power of ejecting when alarmed for the purpose of 

 obscuring the water and hiding its own retreat was formerly used in writing. Cicero mentions this 

 use of it, and from it also is made the true ' sepia ' of artists. I have more than once lately seen it 

 stated that the ink of the Cuttle-fish is 110 longer employed for this purpose, and that ' sepia ' is now 



8BPIA ELEGANS. 



