92 NATURAL HISTORY. 



Another group of crustaceans is parasitic upon fish, and very 

 often kills them. The salt-water catfishes are the commonest 

 victims. If they had enough sense to deliver each other, as the 

 monkeys do, they could very easily turn the tables on their 

 tormentors; which are ugly flat white creatures, sometimes as 

 big as a sixpence, or bigger. 



The most curious, perhaps, of our crustaceans are the hideous 

 " Mantis-shrimps" (Squilla), which get their name from their 

 peculiar claws, deeply-toothed, but not fitted with nippers, some- 

 what resembling those of the Mantis insect (the Indian Daddy-long- 

 legs, that does say his prayers, chiefly grace before meat). Our 

 largest species (8. oratorio) grows to more than a foot long-, and 

 appears to be very sluggish. Some that I kept lay all day half 

 concealed amongst stones and weeds, but with the claws free and 

 ready for action ; and this may, perhaps, be their method of captur- 

 ing live prey. It is likely however that, like most Crustacea, they 

 live a good deal on carrion. Several smaller species are very 

 active. In one of these the armed claws are absent, and the 

 principal legs end in what look like rudimentary nippers, indicating 

 an approach to the lobster's claws. 



I have not got any King-crabs here, but they may very well bo 

 here. They are queer-looking round creatures, with thin legs 

 completely concealed beneath them, and a long sharp spine in their 

 tail ; and are not, indeed, really crabs at all, but more akin to the 

 fossil trilobites ; some naturalists say to the Scorpions. 



The last of the Crustacea are the barnacles and acorn-shells {betlani) 

 which no one, to look at them, would take to be crustaceans at all. 

 Almost every one has seen the common ship's barnacle, a little 

 delicate shell, with several valves, attached by a long worm-like 

 stalk to ship's bottoms, or any other floating matter ; and nearly 

 every one knows the old story of how these barnacles developed into 

 geese. They are very common here; one species is of a bright 

 orange colour, but loses its complexion in spirit. They don't 

 usually attach themselves to stone, with one curious exception, viz., 

 Pumice stone. And in the matter of wood they prefer what is afloat 

 to piling or other fixed timber. 



The Sessile cirripedes (commonly called Acorn-shells), on the other 

 hand, prefer stone and fixed timbers, but are not exclusive. They 

 are sometimes wrongly called limpets, but are easily enough 

 distinguished ; little conical hard shells, with a hole in the top, 



