APPENDIX II 311 



pools and their larvae are truly marine, feeding on green 

 seaweed, and breathing dissolved oxygen by means of 

 gill filaments or over their whole surface (Carpenter, 1899). 

 A list of British seaside Diptera has been compiled by Col, 

 Yerbury (19 19). 



Besides insects, several other kinds of tracheate Arthro- 

 pods may be found between tide-marks. The most incon- 

 spicuous, but, at the same time, the commonest of these, 

 are mites (see p. 65). In addition, a number of Myriapods 

 have been described by Plateau (1890) and Sylvestri (1903). 

 The latter author distinguishes between (a) accidental, 

 (b) indifferent and (c) genuine halophilous forms. According 

 to Plateau, Geophilus maritimus and G. subrnarinus are able 

 to exist in sea- water for periods of twelve to seventy hours. 

 Altogether, Plateau, in 1890, enumerated 40 genera and 80 

 species of tracheate Arthropods known to inhabit the 

 sea-shore, but the list has almost certainly been greatly 

 augmented since then. 



