Zoological Gleanings from the Royal Indian Marine Survey
Ship Investigator.

BY

A. W. ALCOCK, M.B., C.M.Z.S., F.G.S.,
MAJOR, I.M.S.,

Superintendent of the Indian Museum and Professor of Zoology in the Medical College of Calcutta,
formerly Surgeon-Naturalist to the Indian Marine Survey.

" wordπóδεξις wordδε, wordς μήwordε wordword γενόμενα wordword wordρόνword
wordξίwordηλα γένηwordαι. " Herod. Hist. A.

Introductory.

      So many of the biological observations made through the medium of the
" Investigator " are buried in reports that are not accessible, and so many are
scattered through " systematic " papers where they are easily overlooked, that
I have thought it advisable to collect and classify, as a supplement to the
Summary of the Deep-sea Zoological Work published in these Memoirs in 1899,
all such observations as have been recorded since I first became connected with
the ship, together with many hitherto unpublished facts selected from my
Journal.

      I have endeavoured to make this present summary useful to my successors
in the Marine Survey by embodying in it certain references to the literature of
some of the subjects treated. These lists of references are not complete enough
to be dignified by the name of bibliography, but they will answer their purpose
if they serve as beacons to the surgeon-naturalist who finds himself embarked
on these seas for the first time, marking out some of the channels of inquiry that
are open to him.

      The contents of this somewhat miscellaneous paper are grouped under the
following headings:—

      I. Illustrations of Commensalism from the R. I. M. S. Investigator ":—

           1. Among Sponges;

           2. Among Zoophytes;

           3. Among Echinoderms;

           4. Among Crustacea;

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