PRESIDENTIAL ADDRESS. 



63 



A corresponding fauna was described from the "Zone 

 emergee" of the Mediterranean by Prof. Marion. 1 By 

 independence of the water these barnacles have gone far 

 on the way to exchange a marine life for a terrestrial one, 

 but further advance is prevented by the sessile habit. 



No carnivora occur among the molluscs of this upper 

 zone. Only Tectarius and Melaraphe can endure both 

 absence of water, and the full blaze of the sunshine. But 

 where constant shade is obtainable, as in a cave or under 

 a leaning, or a south facing rock, then some barnacles and 

 Acmaea septiformis climb about as high above the sea. 

 Indeed the occurrence of barnacles in such a situation has 

 been misconstrued as proof of a slight recent elevation of 

 the land. 2 



Roaming over the rocks in search of food is a common 

 and most active crab, Leptograpsus variegatus (fig. 28), 



Fig. 28. Leptograpsus variegatus, a crab characteristic of the upper zone 

 of the ocean reef. 



equally at its ease in or out of the sea. Usually it ranges 

 along the edge of the water, following the rising or falling 



1 Marion, Ann. Mus. Marseille, i, 1883, p. 41. 



8 Andrews, Introduction to the Physical Geography of New South 

 Wales, 1909, p. 93. 



