om
these very facts, are either obscure or deceptive. The old writers
content themselves with assigning to any particular shell the
too-comprehensive habitat of "the Indian Ocean," and seldom discriminate
between a specimen from Ceylon and one from the Eastern Archipelago or
Hindustan. In a very few instances, Ceylon has been indicated with
precision as the habitat of particular shells, but even here the views
of specific essentials adopted by modern conchologists, and the
subdivisions established in consequence, leave us in doubt for which of
the described forms the collective locality should be retained.

Valuable notices of Ceylon shells are to be found in detached papers, in
periodicals, and in the scientific surveys of exploring voyages. The
authentic facts embodied in the monographs of Reeve, Kuster, Sowerby,
and Kienn, have greatly enlarged the knowledge of the marine testacea;
and the land and fresh-water mollusca have been similarly illustrated by
the contributions of Benson and Layard in the _Annals of Natural
History_.

The dredge has been used but only in a few insulated spots along the
coasts of Ceylon; European explorers have been rare; and the natives,
anxious only to secure the showy and saleable shells of the sea, have
neglected the less attractive ones of the land and the lakes. Hence Mr.
Hanley finds it necessary to premise that the list appended, although
the result of infinite labour and research, is less satisfactory than
could have been wished. "It is offered," he says, "with diffidence, not
pretending to the merit of completeness as a shell-fauna of the island,
but rather as a form, which the zeal of other collectors may hereafter
elaborate and fill up."

Looking at the little that has yet been done, compared with the vast and
almost untried field which invites explorers, an assiduous collector may
quadruple the species hitherto described. The minute shells especially
may be said to be unknown; a vigilant examination of the corals and
excrescences upon the spondyli and pearl-oysters would signally increase
our knowledge of the Rissoae, Chemnitziae, and other perforating testacea,
whilst the dredge from the deep water will astonish the amateur by the
wholly new forms it can scarcely fail to display.

Dr. Kelaart, an indefatigable observer, has recently undertaken to
investigate the Nudibranchiata, Inferobranchiata, and Tectibranchiata;
and a recently-received report from him, in the Journal of