assumes a red tinge, considerably brighter than brick-dust; and this is
confined to a space so distinct that a line seems to separate it from
the green water which flows on either side. Observing at Colombo that
the whole area so tinged changed its position without parting with any
portion of its colouring, I had some of the water brought on shore, and,
on examination with the microscope, found it to be filled with
_infusoria_, probably similar to those which have been noticed near the
shores of South America, and whose abundance has imparted a name to the
"Vermilion Sea" off the coast of California.[1]

[Footnote 1: The late Dr. BUIST, of Bombay, in commenting on this
statement, writes to the _Athenaeum_ that: "The red colour with which the
sea is tinged, round the shores of Ceylon, during a part of the S.W.
monsoon is due to the _Proto-coccus nivalis_, or the Himatta-coccus,
which presents different colours at different periods of the
year--giving us the seas of milk as well as those of blood. The coloured
water at times is to be seen all along the coast north to Kurrachee, and
far out, and of a much more intense tint in the Arabian Sea. The
frequency of its appearance in the Red Sea has conferred on it its
name."]

The remaining orders, including the corals, madrepores, and other
polypi, have yet to find a naturalist to undertake their investigation,
but in all probability the new species are not very numerous.

* * * * *

NOTE.

TRITONIA ARBORESCENS.

The following is the letter of Dr. Grant, referred to at page 385:--

Sir,--I have perused, with much interest, your remarkable communication
received yesterday, respecting the musical sounds which you heard
proceeding from under water, on the east coast of Ceylon. I cannot
parallel the phenomenon you witnessed at Batticaloa, as produced by
marine animals, with anything with which my past experience has made me
acquainted in marine zoology. Excepting the faint clink of the _Tritonia
arborescens_, repeated only once every minute or two, and apparently
produced by the mouth armed with two dense horny laminae, I am not aware
of any sounds produced in the sea by branchiated invertebrata. It is to
be regretted that in the memorandum you have not mentioned your
observations on the living specimens brought you by the sailors as the
animals which produced the sounds. Your authentication of the hitherto
unknown fact, would probably