98 Dr Grant’s Observations on the Structure and 
infesting the cavities of sponges ; and says, that they open their 
mouths, to allow small animalcules to enter, and shut them in, 
to destroy them when caught. These different animals, how- 
ever, he states, merely shelter themselves, and are nourished in 
the cavities of the sponge ; they become the prey of small fishes 
when the sponge is torn from its seat ; and even the broken re- 
mains of the sponge are consumed by the same fishes. But he 
mentions, that the remains of a sponge thus torn from its place 
may continue to grow upon the rock, and become a complete 
sponge ; that sponges, in deep and sheltered situations, have a 
softer texture than in places exposed to the winds and tempests, 
which check their growth and render them harder ; and that 
they grow best near the shore, in situations, however, where 
they may be completely covered at high-water, because they are 
thus washed and cooled by every access of the tide. He speaks 
strongly of the injurious effects of high temperature on these 
animals ; and says, that it causes them to run rapidly into pu- 
trefaction. This remark of Aristotle I have found of service, in 
keeping sponges alive for the following experiments. The spe- 
cies found on the coast of Lycia, he states, were of great 
magnitude, but of a rare and loose texture. He gives a descrip- 
tion of three different species of this animal, which he character- 
izes by the looseness or compactness of their texture. Those 
which are compact, he says, are generally softest ; and he men- 
tions, that the helmets and sandals of the Grecian warriors were 
lined with a strong compact kind of sponge. From an expres- 
sion which he uses, he even insinuates, that the helmet of Achil- 
les, the hero of the Iliad and of the Trojan war, was lined with 
the same substance : thus giving the employment of this extra- 
ordinary animal in the arts an antiquity of 3000 years. 
From such a remote origin of the study of this animal, its 
natural history is now greatly advanced ; for we are at present 
acquainted with nearly as many species of the sponge as of any 
other animal in the creation. Independent of* the subordinate va- 
rieties under each species, which amount often to three, sometimes 
even to four, as in the Spongia pala of Lamouroux, Linnaeus has 
described 14 distinct species ; Pallas 27, Gmelin 45, Lamarck 
138, and Lamouroux 163 species of marine sponge. Guettard 
even divided the species into seven great genera ; Kponge , Mane , 
