IN DEFENSIVE COLORATION 357 



commonly carries on its borrowed shell the conspicuous 

 stinging sea-anemone Sagartia parasitica ; while an- 

 other English species, Pagurus prideauxii*, inhabits 

 a shell which is invariably clothed by the flattened 

 Adamsia palliata. Two crabs (Polydectus cupulifer* 

 and Melia tessellata*\ from Mauritius, described by 

 Mobius, invariably held a sea-anemone in each claw. 



Two other groups of animals, sponges and Ascidians, 

 in addition to sea-anemones, are avoided by enemies of 

 the Crustacea, and these are also employed by the latter. 

 Thus the British hermit-crab Paguriis cuanensis* is 

 found in shells which are covered with a (generally) 

 brightly-coloured sponge (Siiberites domuncula). Mobius 

 also describes a Mauritian hermit-crab (Ascidiophilus 

 caphyraeformis*} which lives in a case formed by an 

 Ascidian. 



C. EPISEMATIC OR RECOGNITION CHARACTERS. 



Episematic Colours are the logical antithesis of Apo- 

 sematic, their object being to assist in keeping friends toge- 

 ther instead of keeping enemies at a distance. Episematic 

 markings help the individuals of the same species to keep 

 together when their safety depends upon numbers, or to 

 follow each other to a place of safety, thus enabling the 

 young and inexperienced to profit by the example of the 

 older. Episematic characters are far less common than 

 Aposematic, and these than Cryptic ; although, as regards 

 the latter comparison, the opposite impression is generally 

 produced from the very fact that concealment is so 

 successfully effected. 



The white patch near the tail which is frequently seen 

 in the gregarious Ungulates, such as the Red Deer*, 

 and is often rendered conspicuous by adjacent black 

 markings, probably assists the individuals in keeping 

 together ; and appearances with perhaps the same inter- 

 pretation are found in many birds. The white, upturned 

 tail of the Rabbit * is probably of use in enabling the 

 individuals to follow each other readily. Many of the 

 sounds made by animals probably have the same meaning, 

 as also the characteristic flicking movements with which 



