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

'CRUSTACEA. 301already given of it in the ' Catalogue of New-Zealand Crustacea'will apply equally well to the smaller Australian examples, exceptthat iu these latter the eyes are distinct and dark-coloured, theantero-lateral prolongations of the first thoracic segment (in thesmallest specimen especially) somewhat narrower at base, and theposterior margin of the terminal postabdominal segment somewhatarcuated*.The type of Fabricius's Cymotlioa imhricata is also in the British-Museum collection (from the collection of Sir J. Banks), and I amenabled to identify Leach's species with it with tolerable certainty.The slight notch in the terminal segment mentioned by Fal)ricius is,I think, merely due to an accident. As White referred Fabricius'sCi/mothoa imhricata to the genus Nerocila, and the type, when myNew-Zealand Catalogue was published, had not been placed in thegeneral collection of the Museum, I did not then suspect its identitywith C. hanhsii. The species in the New-Zealand Catalogue (p. 107)which I designated, after White, Nerocila imhricata must be calledNerocila madeai/ii, White having previously nsed this name for it(vide Dieffenb. Voy. New Zealand, ii. p. 268, 1813).It is not improbable that the original C. trigonocepluda. Leach,must also be regarded as synonymous with this species ; nevertheless,as the type specimens (which are dried and without definitelocality) present certain slight distinctive characters, as {e. g.) thehead is narrower, more distinctly triangulate, with straight sides,and the anterior thoracic segment proportionately longer than isusual in C. imhricata, I keep tliem provisionally distinct {cf. Ann.& Mag. Nat. Hist. ser. 5, v. p. 4(33, 1880). To ascertain the truedistinctive characters of the species of this difiicult group, a carefulrevision of the whole subject is needed. Milne-Edwards's descriptionof C. tri(jonocephala in the Histoire natureUe ' des Crustacesseems to have been drawn up from specimens of a variety having amore obtuse front, and the anterior margin of the first thoracic segmentarmed with a median lobe or tooth. Specimens presentingthese characters are in the British-Museum collection from SharkBay. Mr. Haswell, in his Catalogue, and Thomson (t. c.) merelycopy ]k[.-Edwards's description.I refer specimens in the Museum collection to Ceratotlioa imhricatafrom Port Essington (Haslar Hospital) ; Sydney, Murray River{A. E. Craven, from the mouth of a salmon-trout) ; Shark Bay, W.Australia (from a species of Monacanthus) ; Calcutta (designated byWhite C. approximans) ; and various other specimens without specialindication of locality.3. Cirolana multidigitata, Dana.A small female from Albany Island belongs, I think, to thisspecies.* The posterior margin in Leach's typo is sliglitij rolled in througli the desiccationof the specimen ;it should not have been described as " nearly straight."