In the department of Entomology much has already been achieved; but an extended area still invites future explorers; and one which the Notes of Mr. Walker prefixed to the List of Insects in this volume, show to be of extraordinary interest, from the unexpected convergence in Ceylon of characteristics heretofore supposed to have been kept distinct by the broad lines of geographical distribution.
Relative to the inferior classes of Invertebrata very little has as yet been ascertained. The Mollusca, especially the lacustrine and fluviatile, have been most imperfectly investigated; and of the land-shells, a large proportion have yet to be submitted to scientific examination.
The same may be said of the Arachnida and Crustacea. The jungle is frequented by spiders, phalangia[6], and acarids, of which nothing is known with certainty; and the sea-shore and sands have been equally overlooked, so far as concerns the infinite variety of lobsters, crayfish, crabs, and all their minor congeners. The polypi, echini, asterias, and other radiata of the coast, as well as the acalephæ of the deeper waters, have shared the same neglect: and literally nothing has been done to collect and classify the infusoriæ and minuter zoophytes, the labours of Dr. Kelaart amongst the Diatomaceæ being the solitary exception.
Nothing is so likely to act as a stimulant to future research as an accurate conception of what has already been achieved. With equal terseness and truth Dr. Johnson has observed that the traveller who would bring back knowledge from any country must carry knowledge with him at setting out: and I am not without hope that the demonstration I now venture to offer, of the little that has already been done for zoology in Ceylon, may serve to inspire others with a desire to resume and complete the inquiry.
J. EMERSON TENNENT
London: November 1st, 1861.
Footnote 1: [(return)]
Ceylon: An Account of the Island, Physical, Historical, and Typographical; with Notices of its Natural History, Antiquities, and Productions. By Sir JAMES EMERSON TENNENT, K.C.S., LL.D., &c. Illustrated by Maps. Plans, and Drawings. 2 vols. 8vo. Longman and Co., 1859.
Footnote 2: [(return)]
An Historical, Political, and Statistical Account of Ceylon and its Dependencies, by C. PRIDHAM, Esq. 2 vols. 8vo., London, 1849.
Footnote 3: [(return)]
An exception occurs in the list of shells, prepared by Mr. SYLVANUS HANLEY, in which some whose localities are doubtful have been admitted for reasons adduced. (See p. 387.)