Report on the zoological collections made in the Indo-Pacific Ocean ...

226 COLLECTIONS FROM MELANESIA.Richters^ Decapoda in Mobius' Beitr. zur Meeresfauna der InselMauritius und der Seychellen, p. 148 (1880).In the collection is a male from Thursday Island, Torres Straits,4-6 fms. (No. 130) a female from Port Denison, 4fms. (^o. Ill) ; ;another from Percy Islands, Queensland, obtained at a depth notexceeding 5 fms, (Ko, 91) ; and three small specimens from PortMolle, 14 fms. (No. 93).There are specimens in the British-Museum collection, that appearto be referable to this species, from Australia (,/. S. Boiverhanlc, Esq.)and Sir C. Hardy's Island, dredged in 11 fms., on a bottom of coarsesand (J. B. Juices) ; also from the Philippine Islands, Corregidor{Cuming), Fiji Islands, Totoya (H.M.S. 'Herald'), and New Hebrides{J. MacgilUvray). A specimen from Shark Bay, W. Australia (F. M.Eayner, H.M.S. Herald ' ') has a more coarsely pubescent carapace,and may be distinct.Dana founded A. tomentosus upon a female from Tahiti or Upolu,in which the regions of the carapace were apparently somewhat lessdistinctly defined than in the specimens I have seen, and the granulationsof the chelipedes more irregularlj' disposed.A careful comparison of the descriptions above cited with theseries in the Museum collection shows that certain of the characterswhich have been hitherto regarded as of specific value are by nomeans as constant as has been hitherto supposed.In most of the Australian specimens I have seen the anterolateralmargins are 4-lobed, without any traces of sj^iniform teeth.Indications of these, however, exist in one specimen from Sir C.Hardy's Island, one out of two from the Philippines, and one fromthe New Hebrides in the Museum collection. In most of the specimensthe carapace is clothed with a close velvety pubescence, andthe upper margin of the chelipedes finely and closely granulated;but in the specimen from New Hebrides and one from the Philippinesthe pubescence is much more scanty and the granulations ofthe hands more acute, especially toward the upper margins.The finger-tips of the sjiecies of this genus are generally scarcelyto be described as excavated, but rather as obtuse, and the transitionis effected to Piluinnus by almost insensible gradations throughsuch species as P. dehaani, Miers*, which, indeed, may be merelythe young of A. setlfcr, but differs not only in the acute anterolateralmarginal teeth and finger-tips, but also in the relativelyshorter antero-lateral margins and entireobliteration of the regionsof the carapace. A specimen nearly resembling P. dehaani is inDr. Coppingcr's collection, frorn Port Denison (No. Ill) ; in it, however,the tubercles of the chelipedes are less conical and acute. Inthe small specimens I refer to A. setifer, from Port Molle, the regionsof the carapace are fully as well defined as in the adult.Dr. F. Richters {t. c. p. 148) records this species from the Mauritius: hence its range evidently extends throughout the Orientalregion.Proo. Zool. Soc. p. 32 (1879).