MEANS OF DEFENCE 65 



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. Stiitchbury 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.^ 

 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^ a native on 

 the I. of Matupi, New Britain, who had been bitten by a Conus 

 geographies, and who had at once cut small incisions with a sharp 

 stone all over his arm and shoulder. The blood flowed freely, 



1 W. E. Collinge, Zoologist, 1890, p. 467. 



2 Proc. Linn. Soc. N. S. Wales, ix. p. 944, 



VOL. Ill F 



