Fig. 25.—Xenophora (Phorus) conchyliophora Born., concealed by the stones which it glues to the upper surface of its shell. (From a British Museum specimen.)
Fig. 26.—Xenophora (Phorus) pallidula Reeve. A mollusc which escapes detection by covering itself with dead shells of other species. (From a Challenger specimen in the British Museum, × ½.)
The formidable spines with which the shells, e.g. of the Murex family, are furnished must contribute greatly to their protection against fishes, and other predatory animals. Murex tenuispina, for instance (see chap. [ix].), would prove as dangerous a morsel in the mouth of a fish as a hedgehog in that of a dog. Whether the singular tooth in the outer lip of Leucozonia (see chap. [xiv].), a feature which is repeated, to a less marked extent, in Monoceros and several of the West Coast muricoids, is developed for defensive purposes, cannot at present be decided.
The Strombidae possess the power of executing long leaps, which they doubtless employ to escape from their foes. In their case alone this power is combined with singular quickness of vision. On one occasion Mr. Cuming, the celebrated collector, lost a beautiful specimen of Terebellum, by the animal suddenly leaping into the water, as he was holding and admiring it in his hand. Miss Saul has informed me that the first living specimen of Trigonia that was ever obtained was lost in a similar way. It was dredged by Mr. Stutchbury in Sydney Harbour, and placed on the thwart of a small boat. He had just remarked to a companion that it must be a Trigonia, and his companion had laughed at the idea, reminding him that all known Trigonia were fossil, when the shell in question baffled their efforts to discover its generic position by suddenly leaping into the sea, and it was three months before Mr. Stutchbury succeeded in obtaining another.
Some genera possess more than merely passive means of defence. Many Cephalopoda emit a cloud of inky fluid, which is of a somewhat viscous nature, and perhaps, besides being a means of covering retreat, serves to entangle or impede the pursuer. The formidable suckers and hooks possessed by many genera in this Order are most dangerous weapons, both for offence and defence. Aplysia, when irritated, ejects a purple fluid which used to be considered dangerously venomous. Many of the Aeolididae, including our own common Aeolis papillosa, possess stinging cells at the end of their dorsal papillae, the effect of which is probably to render them exceedingly distasteful to fish.
The common Vitrina pellucida has a curious habit which in all probability serves for a defence against birds in the winter. When crawling on the edge of a stone or twig it has the power of suddenly jerking its ‘tail,’ so as to throw itself on the ground, where it is probably lost to sight among decaying leaves. At other times it rolls away a few inches and repeats the jump. It also possesses the power of attaching to itself bits of leaves or soil, which entirely cover and conceal both shell and animal.[145] The property of parting with the tail altogether, a remarkable form of self-defence, has already been noticed on p. [44].
The poisonous nature of the bite of certain species of Conus is well authenticated. Surgeon Hinde, R.N., saw[146] a native on the I. of Matupi, New Britain, who had been bitten by a Conus geographus, and who had at once cut small incisions with a sharp stone all over his arm and shoulder. The blood flowed freely, and the native explained that had he not taken these precautions he would have died. Instances have been recorded of poisonous wounds being inflicted by the bite of Conus aulicus, C. textile, and C. tulipa. According to Mr. J. Macgillivray[147] C. textile at Aneitum (S. Pacific) is called intrag, and the natives say it spits the poison upon them from several inches off! Two cases of bites from C. textile occurred to this gentleman’s notice, one of which terminated fatally by gangrene. Sir Edward Belcher, when in command of the Samarang, was bitten[148] by a Conus aulicus at a little island off Ternate in the Moluccas. As he took the creature out of the water, it suddenly exserted its proboscis and inflicted a wound, causing a sensation similar to that produced by the burning of phosphorus under the skin. The wound was a small, deep, triangular mark, succeeded by a watery vesicle. The natives of New Guinea have a wholesome dread of the bite of Cones. Mr. C. Hedley relates[149] that while collecting on a coral reef he once rolled over a boulder and exposed a living C. textile. Before he could pick it up, one of the natives hastily snatched it away, and explained, with vivid gesticulations, its hurtful qualities. On no account would he permit Mr. Hedley to touch it, but insisted on himself placing it in the bottle of spirits.
Fig. 27.—A tooth from the radula of Conus imperialis L., × 50, showing barb and poison duct.