
454 SPONGES. 
` port; some being fixed to rocks, others to shells, and indeed 
any submarine objects which may present a surface strong 
enough to answer the purpose required. It is remarkable, 
but nearly all the specimens I have examined of this sponge 
have had enclosed in them a common hermit or soldier-crab. 
How this pugnacious member of the crustacean class be- 
. comes imprisoned it is difficult to conceive. Dr. Gray, of 
the British Museum, in speaking of them in “Land and 
Water,” a London periodical, says that “the natives of the 
Philippine Islands deny that they are sponges, but say that 
they are formed by the crabs that are usually found in them, 
and that a pair of crabs form two close together. Hence 
they regard two specimens, as we should call them, a single 
individual." They consist of pure silica,, and Mr. C. G. 
Brewster, naturalist, Boston, to whose courtesy I am in- 
debted for the accompanying faithful engraving, has several 
specimens which, having lost their outer covering or film, 
have been cleaned by being placed in a weak solution of 
chloride of lime, and all wards exposed to the action of 
the atmosphere. The Euplectella is found principally near 
the island of Zebu, one of the Philippine's, where the first 
specimen was obtained by the late Hugh Cuming. 
The forms of sponges are very irregular; some being 
branched, others round or prts shaped, and others resem- 
bling a cup, like the well known "Neptune's cup" of the 
Tndian Seas. During life they are extremely beautiful in 
colors, possessing tints which it would be impossible to 
describe, and which I do not think have ever been faithfully 
represented in consequence of their beauty departing im- 
mediately after life ceases. Dr. Johnson states that the green 
color of the fresh-water sponge (Spongilla fluviatilis) de- 
pends upon the action of light, as he has proved by experi- 
ments which showed that “pola colored specimens þecame 
green when they were exposed for a few days to the light 
and full rays of the sun; while on the contrary, green speci- 
mens y were blanched ^a being made to grow in darkness OF 

