lead to the discovery of the same
phenomenon in other common accessible paludinae, and other allied
branchiated animals, and to the solution of a problem, which is still to
me a mystery, even regarding the _tritonia_.

My two living _tritonia_, contained in a large clear colourless glass
cylinder, filled with pure sea water, and placed on the central table of
the Wernerian Natural History Society of Edinburgh, around which many
members were sitting, continued to clink audibly within the distance of
twelve feet during the whole meeting. These small animals were
individually not half the size of the last joint of my little finger.
What effect the mellow sounds of millions of these, covering the shallow
bottom of a tranquil estuary, in the silence of night, might produce, I
can scarcely conjecture.

In the absence of your authentication, and of all geological explanation
of the continuous sounds, and of all source of fallacy from the hum and
buzz of living creatures in the air or on the land, or swimming on the
waters, I must say that I should be inclined to seek for the source of
sounds so audible as those you describe rather among the pulmonated
vertebrata, which swarm in the depths of these seas--as fishes, serpents
(of which my friend Dr. Cantor has described about twelve species he
found in the Bay of Bengal), turtles, palmated birds, pinnipedous and
cetaceous mammalia, &c.

The publication of your memorandum in its present form, though not quite
satisfactory, will, I think, be eminently calculated to excite useful
inquiry into a neglected and curious part of the economy of nature.

I remain, Sir,

Yours most respectfully,

ROBERT E. GRANT.

_Sir J. Emerson Tennent, &c. &c._

CHAP. XII.

INSECTS.

Owing to the favourable combination of heat, moisture, and vegetation,
the myriads of insects in Ceylon form one of the characteristic features
of the island. In the solitude of the forests there is a perpetual music
from their soothing and melodious hum, which frequently swells to a
startling sound as the cicada trills his sonorous drum on the sunny bark
of some tall tree. At morning the dew hangs in diamond drops on the
threads and gossamer which the spiders suspend across every pathway; and
above the pool dragon-flies, of more than metallic lustre, flash in the
early sunbeams. The earth teems with countless ants, which emerge from
beneath its surface, or make their devious highways to ascend to their