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[Read before the Philosophical Institute of Canterbury, 7th December, 1910.]
The Crustacea described in this paper are mainly the result of collections made by Mr. W. R. B. Oliver and his companions during their stay on the Kermadec Islands in 1908; but included among them are several that had previously been collected at the islands by Captain Bollons, of the Government steamer “Hinemoa,” and by him kindly handed over to me.
Mr. Oliver has very generously intrusted his whole collection to me for identification, and has supplied me with a number of notes on the occurrence, habits, &c., of many of the species, most of which are incorporated below. The collection proves to be a very representative one of the crustacean fauna of the islands, including marine and shore forms, and also the few land and fresh-water species that were to be obtained.
Altogether it comprises 83 species, grouped as follows: Decapoda, 47; Euphausiacea, 1; Amphipoda, 14; Isopoda, 10; Cirripedia, 4; Ostracoda, 2; Branchiopoda, 1; Copepoda, 4. It will be seen that although the majority of the species belong to the Decapoda, as comparatively little attention could be devoted to the smaller forms, still nearly all the other divisions of the Crustacea are represented. The identification of all the forms of the different groups has been a somewhat difficult task in the absence of any large collection of named specimens for comparison and of some of the necessary works of reference. I have endeavoured in all cases to indicate the description on which I have relied for the identification, and, when necessary, to state briefly the points in which my specimens appeared to differ.
A few Crustacea were obtained by the “Challenger” Expedition by means of dredgings in the neighbourhood of the Kermadecs, but so far as I am aware no previous collection has been made actually at the Kermadec Islands themselves, and it is therefore perhaps a little surprising that nearly all the specimens prove to belong to species already known. A few new species are described, but the proportion of these is very small considering that the collection comes from an absolutely new locality, and even some of these new species must be looked upon as confessions of ignorance. However gratifying it may be to describe new and peculiar forms, it is still more pleasing to find how completely the more conspicuous members of the crustacean fauna of the seas surrounding the Kermadecs are now known. This prepares the way for attacking questions of distribution. In this paper, however, I cannot enter fully into this matter, and can merely state that nearly all the marine and littoral species are Australian or Indo-Pacific forms, many of them being already known from the east coast of Australia, New Caledonia, Lord Howe Island, or Norfolk Island, though several are now recorded from this region for the first time. Comparatively few of the marine forms extend to New Zealand. The affinities
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of the few land and fresh-water forms are somewhat indefinite, owing to the incompleteness of our knowledge of these forms from neighbouring lands, but on the whole they appear to show more connection with New Zealand than the marine forms do.
A few of the species from the Kermadecs are of especial interest—e.g., the occurrence at these islands of the amphipod Eurythenes gryllus still further extends the distribution of this large amphipod, which has already attracted so much attention. It is perhaps worth while calling attention to the occurrence at the Kermadecs, and to the habits of Actaeomorpha erosa, Cryptochirus coralliodytes, and Porcellanopagurus tridentatua.
Sufficient information about the size, position, &c., of the Kermadecs will be found in the papers by Mr. W. R. B. Oliver* and Mr. R. Speight† in a previous volume of the Transactions. Mr. Oliver has dealt specially with the botany, while some of the groups of animals have been already investigated by Mr. Edgar R. Waite,‡ Professor W. B. Benham, § Dr. F. W. Hilgendorf, ∥ Professor H. B. Kirk, ¶ and Mr. T. Iredale.** It will be sufficient to state here that the Kermadecs form a group of four islands lying in a line extending from Sunday Island (lat. 29° 50′ S., long. 177° 59′ W.) to French Rock (lat. 31° 24′ S., long. 178° 51′ W.). The whole group lies about half-way between New Zealand and the Tonga Islands.
I have followed the classification given by Dr. W. T. Calman in his account of the Crustacea in Ray Lankester's “Treatise on Zoology,” but as a matter of convenience I have placed the Decapoda first. Only those synonyms and references have been given that appear to be necessary.
My hearty thanks are due to Mr. Oliver for the opportunity of examining the collection, and for the thorough manner in which he collected and carefully recorded all the specimens available. I am also indebted to Professor Benham and Messrs. Waite and Hamilton for the loan of books from the libraries under their control.
[Footnote] * “The Vegetation of the Kermadec Islands,” Trans. N.Z. Inst., vol. 42, p. 118
[Footnote] † “Petrological Notes on Rocks from the Kermadec Islands,” Trans. N.Z. Inst., vol 42, p. 241.
[Footnote] ‡ “A List of Known Fishes of Kermadec and Norfolk Islands, and a Comparison with those of Lord Howe Island,” Trans. N.Z. Inst., 42, p. 370.
[Footnote] § “Stellerids and Echinids from the Kermadec Islands,” Trans. N.Z. Inst., 43, p. 140.
[Footnote] ∥ “On some Calyptoblast Hydroids from the Kermadec Islands,” Trans. N.Z. Inst., 43, p. 540.
[Footnote] ¶ “The Sponges collected at the Kermadecs by Mr. Oliver,” Trans. N.Z. Inst., 43, p. 574.
[Footnote] ** “On Marine Mollusca from the Kermadec Islands,” Proc. Mal. Soc., 9, pt. 1, p. 68 (March, 1910).