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Art. XVIII . — Observations and Experiments on the Structure 
and Functions of the Sponge . By Robert Edmond Grant, 
M. B., E. R. S. E., F. L. S., M. W. S., &c. Continued 
from Vol. XIII. p. 346. 
SpONGES grow so abundantly on our rocky coasts, and attain 
so considerable a size, that few animals can be said to present equal 
facilities of observing their natural habits, or of discovering their 
properties by experiment. Montagu, many years ago, described 
thirty-nine species inhabiting the British shores ; and nearly half 
that number occur in the Frith of Forth, which will be men- 
tioned individually in describing the skeleton of this animal, and 
the characteristic differences in the forms and arrangement of the 
spicula in different species. Almost every rock along our 
coast, placed near low-water-mark, supports some species of 
sponge ; and, as far as my experience gees, the same is the case 
with every other shore visited by the waves of the ocean. I 
have found them growing alike on the sheltered transition boul- 
ders of the western shores of Italy, as on those which break the 
force of the tempests in the Bay of Biscay ; and I have found 
the most delicate of our British species, spreading alike on the 
stupendous primitive cliffs of the Western Islands, exposed to 
the rapid currents ( and constant swell of the ocean extending to 
the American shores, as on the secondary rocks in the more shel- 
tered bays of our eastern coast. The Spongia papillaris and 
S. urens , line the sea-worn cavities and fissures of quartz, gneiss, 
and granite rocks, on the western promontories of the island of 
Islay ; and the same species spread .over the sheltered hollows of 
the decayed greenstone columns on the coast of Dunbar. In 
the deeper parts of the Frith of Forth, the sponge so much a- 
bounds, as to encumber the dredges employed by our fishermen 
in collecting oysters, mussels and clams ; and when thus tom 
from its native seat, by the long continued and daily opera- 
tion of some hundred dredges, it is washed ashore alive on diffe- 
rent parts of the coast in such quantities, that it is collected with 
other zoophytes and fuci, to manure the adjacent lands. So nu- 
merous are these animals in more southern latitudes, that the 
yon. xiv, NO. 27. JANUARY 1826, H 
