FISHES AS MESSMATES 171 



afforded by a slender form (Fierasfer) living in the gullet of a 

 kind of Sea-Cucumber, which does not appear to gain anything 

 by way of return for its hospitality. Some of the giant sea- 

 anemones living on the Great Barrier Reef of Australia harbour 

 gaily-coloured little fishes belonging to the Perch family, a given 

 species of anemone being the home of a particular species of 

 fish. The fish-guest (Amphiprion percula] of one such obliging 

 zoophyte (Discosoma Kenti) is orange-red in colour, marked by 

 three cross -bands of pearly white, these and the fins being 

 edged with black. An allied anemone (D. Haddoni} entertains 

 a little fish (A. bicinctus) which differs from its relative in 

 possessing two bands only, while the black edging is absent. 



Fig. 1124. Indian Rock Perch (Minous inermis) with Commensal Polypes (Stylactis minot) 



The same anemone also extends its hospitality to a red-and- 

 white Prawn (Palamon). In these cases the fishes not only find 

 a secure shelter, the stinging properties of which ward off 

 attack, but also probably filch some of the food of their living 

 homes. On the other hand, it is possible, as suggested by 

 Saville Kent, who has described the associated animals, that 

 the bright tints of the guests serve as " lure colours ", enticing 

 animals which serve as food for the anemones. 



The relations just described are occasionally reversed, as when 

 a fish serves as a moving home to zoophytes. Alcock describes 

 a Rock Perch (Minous inermis, fig. 1124), native to the Indian 

 Ocean, as being always more or less encrusted with small polypes 

 (Stylactis minoi\ which, being of course carried about from place 

 to place, have a better chance of getting abundant food than if 

 they were attached to a stone or sea- weed. The fish may perhaps 

 derive some protection from the stinging properties of its guests. 



