178 MARVELS OF THE ANIMAL WORLD 



when, becoming alarmed at the unusual situation, 

 they show their displeasure by discharging their 

 ' ink,' which is then easily collected. 



Great care has to be taken to ensure that the 

 cuttle-fish are not unduly disturbed when they are 

 being introduced into their * milking-stalls,' lest 

 they should become annoyed or frightened, and 

 disperse their fluid in the water. 



Other creatures, in addition to those previously 

 mentioned, have the power to eject a fluid secreted 

 by their glands, making use of the same for defen- 

 sive purposes. Darwin, in The Voyage of the Beagle, 

 records having come across a sea-slug, about five 

 inches long, that ' when disturbed emits a very 

 fine purplish-red fluid, which stains the water 

 for a space of a foot around/ The larva of the 

 puss -moth, when irritated, also discharges some 

 liquid from out of a cleft situated in its neck, the 

 squirting apparatus being pierced by a number 

 of holes like those in the ' rose ' of a watering-can. 



Before concluding our survey of animal weapons, 

 mention must be made of the sword-fish and the 

 saw-fish, both of which are armed with very formid- 

 able instruments of defence and offence. The 

 former, which may measure as much as fifteen 

 feet in length, is remarkable in the fact that its 

 upper jaw is furnished with a long, wedge-shaped, 

 and sword-like weapon, by means of which it trans- 

 fixes the bodies of other fish that constitute its 

 prey. It will also attack whales, and has even 

 been known to charge at ships (probably mistaking 

 the bottom of a vessel for one of the cetaceans), 



