CONSTRUCTION OF SHELLS. 13 
beautifully harmonized with a multitude of marine 
plants, that fringed the black and white rocks with 
tints of purple, grey, rust-coloured brown, and green, 
and presented, in the variety of their forms, long 
tufts of various colours, garlands, festoons, and cord- 
ages, agitated by the waves in every possible manner. 
Different kinds of shell-fish, such, especially, as 
seldom move from their customary stations, are 
clothed, obviously with the same design, either in a 
brown and shaggy garment, mud-coloured tartar, 
or thin epidermis, in accordance with the colours 
of their respective places of retreat. This extra- 
ordinary provision is particularly observable in differ- 
ent species of Solen, Tellina, Patella, and Venus, 
and in several individuals of the numerous division 
of Univalve ; while they conceal beneath their gloomy 
upper coats, pearly tints and appearances, which not 
unfrequently exceed the brilliant hue of the most 
gaudy shell-fish. Thus the Magellan Limpet, when 
disrobed of its unsightly garment by the application 
of muriatic acid, presents a polished surface resem- 
bling the finest tortoise-shell, blended with burnished 
gold. The Trochus-Iris conceals in like manner a 
splendid metallic lustre; and numerous species of 
the genus Mya, which are covered with a thick brown 
or green epidermis, present a brilliant and polished 
surface, glowing with the colours of the rainbow. 
