Go to National Library of New Zealand Te Puna Mātauranga o Aotearoa
Volume 9, 1876
Previous Article | Table of Contents | Next Article
This text is also available in PDF
(627 KB) Opens in new window
– 475 –

Art. LXV.—Notes on the Genera Astacoides and Paranephrops.

By Edward J. Miers, Assistant in the Zoological Department, British Museum.

*

In the “Annals” for last month Professor J. Wood-Mason published a very interesting note “On the Mode in which the Young of the New Zealand Astacidœ attach themselves to the Mother.” He states (p. 306) that he observed this peculiar mode of attachment in the young of “a female of Astacoides zealandicus,” which, he adds in a foot-note, “= Paranephrops setosus, Hutton;” and, in another foot-note, he cites the genus Paranephrops of White as synonymous with Astacoides of Guérin-Méneville. As it appears to me still uncertain to what species Professor Wood-Mason refers in his communication, the following observations may be of interest.

Guérin-Méneville founded the genus Astacoides, in April, 1839, † for a species of Crayfish described as occurring very frequently in the rivers of Madagascar, to which he applied the name of A. goudotii, after its dis-

[Footnote] * From “The Annals and Magazine of Natural History” for November, 1876, p. 412. † “Bevue Zoologique,” II., p. 109 (1840).

– 476 –

coverer, M. Goudot. This species was noticed almost almost contempoaneously by M. Milne-Edwards, * and subsequently described at greater length and well figured by him, † under the name of A. madagascariensis. Of this species, unfortunately, no specimens are in the collection of the British Museum; but the published descriptions and figure suffice, I think, to show that the genus is well characterized by its robust form, powerful anterior legs, with broad hands and short palm, and the position of the antennæ, which are inserted beneath the antennules and are furnished with a small or rudimentary basal scale.

In the genus Paranephrops of White, ‡ as exemplified in the typical species P. planifrons, which is also the commonest species of the genus, the body is comparatively slender, the anterior legs elongated, with the palm more than twice as long as broad, and clothed externally with longitudinally seriate tubercles and spines; moreover the antennæ are inserted externally to the antennules, and are furnished with a very large basal scale, which is longer than the peduncle of the antennæ. It is true that in other species of both genera (as, for example, Astacoides serratus, Shaw, and A. franklinii, Gray, from Australia, and Paranephrops zealandicus, White) the distinctive characteristics are somewhat less strongly marked; but so far as the materials in the collection of the British Museum afford means of comparison, I can see no necessity for uniting the genera.

Professor Wood-Mason refers, I believe, to Paranephrops zealandicus, White, § in speaking of “Astacoides zealandicus;” but this species is certainly distinct from P. setosus, Hutton. ∥ In P. zealandicus, of which the type specimens are in the British Museum collection, the hands are clothed externally with tufts of hair, arranged in longitudinal series, and are armed with spines only upon the superior margins, and the sides of the carapace are smooth. In P. setosus there are spines arranged seriately upon the external surface as well as the upper margin of the hand, and the branchial and hepatic regions of the carapace are armed with numerous unequal conical spines. A specimen agreeing well with Hutton's description is in the National collection.

I may say, in conclusion, that a somewhat analogous mode of attachment has been observed among the Edriophthalmata, in the case of the

[Footnote] * “L'Institut,” p. 152 (1839).

[Footnote] † “Archives du Muséum d'Histoire Naturelle,” II., p. 35, pl. iii., figs. 1–5 (1841).

[Footnote] ‡ “Zoological Miscellany,” II., p. 79 (1842).

[Footnote] § Astacus zealandicus, White, “P.Z.S.,” 1847, p. 123; “Ann. and Mag. Nat. Hist.,” ser. 2, i., p. 225 (1848); Paranephrops zealandicus, Miers, “Zool. ‘Ereb.’ and ‘Terr.,’” Crust., p. 4, pl. ii., fig. 2 (1874); “Cat. New Zeal. Crust.,” p. 73 (1876).

[Footnote] ∥ “Ann. and Mag. Hist.,” Ser. 4, Vol. XII., p. 402 (1873).

– 477 –

young of Arcturus, by Sir J. G. Dalyell, whose account is quoted by Messrs. Spence, Bate, and Westwood, in their “History of the British Sessile-eyed Crustacea,” II., p.370. In this genus the young individuals affix themselves in clusters to the antennæ of the mother, clasping the peduncles of those organs with their prehensile three posterior pairs of pereiopoda; and a specimen of A. baffini, actually exhibiting this mode of attachment, is preserved in the collection of the British Museum. The young specimens are clustered chiefly on the under-side of the antennæ, with the head pointing toward the body of the parent. In this instance no specially modified prehensile organ exists, nor, indeed, is such required.

Previous Article | Table of Contents | Next Article