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

356 COLLECTIONS FROM MELANESIA,Obs. The differences between this specimen and the types in theform of the verrucae appear to be due to their more expanded conditionat time of death in this than in the type specimens. Unfortunatelyno spirit-specimens have as yet reached the Museum.MELITH^ID^.Melithfeacete, Kollikei-, Icones Histiol. p. 142.Melitbseadfe, Mopselladis, and Elliselladae, Gray, Cat. Lithoph. Brit.Mus. (1870) pp. 3, 5; 24.The two first-named of Dr. Gray's families cannot possibly bemaintained distinct from each other, as of the genera which he hasplaced iu the first, McJitlum (Melitodes) includes, as is shown by acareful study of the spicular characters, Anicella, which he has placedin the second ; the only distinctive character by which the Melithaiadffiare alleged to be separated from the Mopsellidai, viz. theperforation by the longitudinal coenenchymal canals of the lowerioints of the hard axis, is exhibited also by four out of the five"genera which make up the latter family ; this may readily be ascertainedby examination of adult specimens representing these genera.For this reason I have been obliged to relinquish this character inthe separation of the genera, except in the case of Clathraria andthe new genus Ps'dacaharia, and have in this Eeport reconsideredthe genera and species involved, and after comparing them with therich collection already iu the national museum, embracing almostevery known species, arranged them mainly according to spicularcharacters, thus following the plan which has been adopted withsuch success iu other groups of the Alcyonaria by KoUiker andVerrill, The Elliselladse, Gray, include a Melithseid (Wrightella).The family thus constituted is represented in the present collectionby the proportionally large number of six species, of whichfour are jiew, one appearing to be generically distinct from all otherknown forms, and remarkable further for its pure white colour andslight habit, unexampled in the family. The existence of a dimorphismof the zooids, long known to obtain in the Pennatulida, andtreated of in the Alcyouiidoe (Beteroxenia, Kolliker ; Sarcophytum,Moseley, <strong>Report</strong> etc. 'Challenger,' vol. i. p. 118), and by Prof.Moseleyin the Coralliidse (Quart. Journ. Micr. Science, n. s. vol. xxii. p. 396),and stated by Hickson ((iuart. Journ. Sci. 1883, Oct., p. 574) to occurin the Briareidae (Paragorgia), a fact which I am able to confirmfrom specimens in the British Museum, was also pointed out for thefirst time in the present family by Mr. Hickson, from information withwhich I furnished him, viz. in a new species (J\I. alhitineta) of thegenus Melitodes. In this species, the only one of between 20 and 30species of the family in which I have observed it, this phenomenonoccurs in a somewhat remarkable manner, partly owing to which Ihad at first overlooked it ; but on my attention being called by theartist, Mr. Highley, to certain projections on some of the branches,larger than the ordinary verrucse, I examined the corallum more