AXP THE FISH THEREOF. u 



brackish waters ; in other places Heteractis, Oscillaria, and other kinds 

 abound. On rocky shores the upper edge is covered with the periwinkle 

 (Litorina B aster oti) \ Ligia Brandtii from above, and Grapsus varius from 

 below, meet here ; below this, several species of the littoral shell-fish limpets 

 {Patella) adhere to the rocks near the water's edge, also Chiton Polii. About 

 midway between the tide-marks appears the advance-guard of the Balani 

 (barnacles), which grow on the rocks so as to belt the coast when the tide is 

 out ; the representative species is in this case Chthamalus stellatus. On spots 

 retaining the moisture after the receding tide Nereis cultrifera, Heterocirrus 

 saxicola, Sipunculus verrucosus^ and Mytilus minimus are commonly to be seen. 



Below these, again, as far as low-water mark, whole groups of Mytilus 

 minimus, and, in hidden places attached to the rocks, the date-shell, 

 (Lithodomus lithophagus), and the indolent Actinia mesembryantJiemum, one 

 of the few Red-Sea polyps l found in the Mediterranean region, and one of 

 the most characteristic forms of this zone, never moving during the whole 

 period of its exposure to the air, whereas species of TrocJms? which here 

 first make their appearance, and Grapsus varius, a marginal crab, follow the 

 receding tide, remaining exposed to the air at most for one or two consecutive 

 hours. 



Shores exposed to the breakers are overgrown with Fucus vesiculosus, and 

 the genera are limited here to Mytilus minimus, Trochi, and Grapsus varius 

 already mentioned. On shingle, sandy, or muddy shores, also when covered 

 with sea-weed, and where the moisture is retained at low water, Amphitoe 

 penicillata is characteristic, being found here in large numbers, besides 

 Gammarus Olivii, in second order. 



On muddy, but sheltered, flat shores we find species of the rag- worm 

 {Nereis) ; where sand predominates, Gebia littoralis, an elegant green and 

 sandy-coloured, marbled shore-crab, which swims backwards and forwards ; 



1 A sea-anemone like masses of brilliant crimson, or bright green pulp, but, when covered by 

 the water, expanding into many armed disks and displaying shapes and colours of exquisite 

 beauty. — E. Forbes. 



2 Trochus divaricatus, the purple-striped top-shell, remains exposed to the air on moist 

 shores. — E. F. 



C 2 



