OCR Text |
Show 1900.] FROM THE FALKLAND ISLANDS. 549 Jcera and Iais closely correspond; though the antepenultimate joint of the maxillipeds is rather less strongly developed in Iais than in Jcera, and, on the other hand, the inner plate of the first maxillae is broader in Iais. IAIS PUBESCENS (Dana). (Plate XXXVIII.) 1853. Jcera pubescens, Dana, U.S. Expl. Exp. vol. xiii., Crust. p. 744, pi. 49. figs. 9 a-cl. 1876. Jcera pubescens, S. I. Smith, Bull. U.S. Nat. Mus., Contr. Nat. Hist. Kerguelen, p. 63. 1882. Jcera novce zealandice, Chilton, Tr. N e w Zealand Inst. vol. xv. p. 189. 1886. Iais hargeri, Bovallius, Notes on Fam. Asellidae, p. 50. 1886. Iais pubescens, Bovallius, ibidem, p. 51. 1886. Icera novce-zelandice, Bovallius, ibidem, p. 49. 1886. Jcera neo-zelanica, Thomson & Chilton, Tr. N e w Zealand Inst. vol. xviii. p. 157. 1886. Jcera pubescens, Beddard, ' Challenger' Isopoda, Beports, vol. xvii. p. 19, pi. 2. figs. 6-13. 1887. Iais(Janthe) pubescens, Pfeffer, Krebse von Siid-Georgien, p. 19. 1887. Jcera antarctica, Pfeffer, ibidem, pp. 19 & 94, pi. 7. figs. 1-4. 1888. Iais neo-zecdaniea, Chilton & Thomson, Tr. N e w Zealand Inst. vol. xxi. p. 265 (Iais pubescens evidently intended). 1891. Iais pubescens, Chilton, Trans. New Zealand Inst. vol. xxiv. p. 266. 1893. Jais pubescens, Thomson, P. B. Soc. Tasmania for 1892, p. 15 (Jais misprint for Iais). The association of this minute species with Sphceroma lanceolatum (or gigas) is recorded by Dana for Tierra del Fuego, by Professor Smith and Mr. Beddard for Kerguelen Island. That they are all three applying the name to the same species is, therefore, highly probable. But Smith gives no description; and Beddard's description is accompanied by figures which do not in all respects agree with our specimens from the Falkland Islands, the segments of the body showing little or no lateral interval, and the head having its front and sides curiously serrate. From the text, however, it must be inferred, as Dr. Chilton has already pointed out, that at least the second of these differences is due only to an error on the part of the draughtsman; the first apparently depends on a very advanced stage of the brood-pouch in the female. That the rami of the uropods are in the figure distally clubbed instead of tapering, may well be due either to a casual variation or a slight inaccuracy in the drawing. Iais hargeri Bovallius, from the Strait of Magellan, differs in nothing from the Falkland Island specimens, unless in size (" 3-4 mm.") and in one or two comparative measurements of parts, which can scarcely be trustworthy, since they vary with the bending or straightening and other accidental conditions of the specimen |