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

362 COLLECTIONS FROM MELANESIA.lemon-yellow. The species has to be referred to Acaharia, as itwants the foliated spicules (Blattkeulen) characteristic of Mopsella.Hab. Port Darwin, Australia, 8-15 fms. ; bottom mud.Ohs. The distribution of this specie^, hitherto known only fromJapan, is not by any means unparalleled (cf. Echinomuricea inclomalaccensis,p. 336, extending from China to jST.E. Australia) ; thespecies has not hitherto been recorded from anj^ point betweenAustralia and Japan.Dana's species (v. supra), from the Sandwich Islands, is probablynearly allied if not identical with this, but the original description isinsufficient to decide the point.36. Acabaria serrata.(Plate XXXVII. figs. E, E' ; Plate XXXVIII. figs, c-c".)Corallum erect, branching dichotomously at angles of 30° to 40°,strictly in one plane ; anastomosis absent or rare. Base ? Main stemslender, not exceeding 2-5 millim. in diameter. Internodes slender,slightly flexuous, 8-10 millim. long as a rule, compressed fromfront to back, decreasing slightly in diameter towards periphery,viz. from about 1-5 millim. lateral diameter near base to -75 millim.at tips of branches (exclusive of tubercles) ; antero-posterior diameteronly about half as great as the lateral diameter. Internodescompact, apparently imperforate throughout ; axis deep crimsonred.Soft joints distinct, spherical, nearly twice the diameter(taken laterally) of the adjacent internodes, except near periphery,where they are no thicker than the internodes ; substance compact,deep crimson.Cortex very thin, but compact, smooth, deep crimson (in spirit) inadult, white to pale scarlet in young specimens. Verrucse usuallyforming a strictly single row down each lateral margin of thebranches ; in closed state rounded and but slightly prominent ; inopen state truncate-conical, about "5 millim. in height, serrating theedges of the branches in a manner peculiar to this species in its genus ;their bases are just free from each other; colour (in spirit) pale yellow.Spicules of cortex (i.):— Fusiform or subclavate, curved, tuberculato,one end usually well pointed, the other more or less obscured at oneside by projection of large tubercles ; tubercles distinct from eachother, but not arranged in whorls, long, pointed, rather ragged ;those of the convex side very prominent towards the larger endand inclined towards this end ; size -21 by -062 millim. (ii.) Smaller,shorter, blunt or almost so, with thick shaft and two median whorlsof tubercles, low, rough, transversely elongated, forming almostcontinuous ridges round the spicule, and a whorl of incipient tuberclessurrounding each blunt end ; size '088 to '12 by -053 millim.Spicules of verrucae (iii-) :— Horizontal, fusiform, curved, taperingmore or less, the middle beset with few, low, and rounded tubercles,more or less roughened towards the ends ; size "21 to '2o by '024to -030 millim. (iv.) Longitudinal spicules, apparently almost the