344 WRECKED MEDUSA. 



formed by nature ; but it has been built up in some 

 places so as to make it a perfect reservoir. Being 

 overflowed by tlie sea at high-water, its, purity is 

 renewed twice every day, and as it retains its contents 

 when the tide recedes, it remains always full, a pond 

 of nearly an acre in extent, and of considerable depth. 

 Though far above low-water mark its depth and con- 

 stant fulness make it a favourable locality for many 

 sea-weeds, which under ordinary circumstances would 

 thrive only at a level very much lower. The shelving 

 sides, especially in the deeper parts, and where the 

 artificial wall has been supplied, are densely fringed 

 with Laminarice, and many fine species of the 

 FloridecB in great luxuriance. 



It was at the leeward side of this pond that I hap- 

 pened first to look, and there in the nooks and comers, 

 driven up by the wind, were several very flat Medusae 

 of large size lying motionless upon the floating weeds, 

 and many more of a smaller species crowded together 

 upon the surface of the water. The latter were, as I 

 guessed at the first glance, Thaumafitias pilosella, all 

 dead, mostly covered with minute air-bubbles, and in 

 many cases totally deprived of the sub-umbrella, with 

 all the organs, leaving nothing but the gelatinous 

 umbrella. 



I walked around the pond, and found the same 

 accumulation in most of the comers on the lee side. 

 Thence down to the edge of the rocks, where the sea 

 was dashing in with fury; there too in the inlets and 

 crevices of the rocks, were the same two sorts driven 

 in, the former by dozens, the Thaumantias by 

 hundreds. 



