ANURIDA. 429 



COLLEMBOLA. 



Among the Collembola a marine habitat has been 

 independently acquired by species belonging to both the 

 Entomobryidse and Achorutidse but, up to the present, 

 none of the Sminthurida? are known to frequent the 

 confines of the sea-shore. 



In addition to Anurida maritima, the following 

 species of marine Collembola occur in the British Isles. 

 Those species indicated with an asterisk are not 

 exclusively marine, but are also found far inland. 



Isotoma littoralis, Mon. *Xenylla humicola, Tullb. 



*I. palitstris (Mull.) *X. maritima, Tullb. 



/. Schotti, Dalla Torre. Actaletes neptuni, Giard. 



/. Beselsii, Pack. (= Isotoma crassicauda, 



*L maritima, Tullb. Tullb.) 



*J. sexoculata, Tullb. '*Achoru£es viaticus, Tullb. 



Thysanura. 



Machilis maritima (Leach). 



Coleoptera. 



The greater number of marine representatives of this 

 order consist of wingless forms, and many of them have 

 their bodies very much flattened, which enables them to 

 ensconce themselves in small crannies and fissures among 

 the rocks during the time they are submerged by the sea. 

 Their bodies are frequently covered with a coating of 

 hairs, which prevents them from being wetted, and also 

 encloses a certain amount of air, which is utilised during 

 respiration under water. Marine beetles hide themselves 

 by burrowing in the sand, or lurking under stones or 

 decaying seaweed ; at low tide they may be often seen 

 running over the rocks or sands, 



