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

;ALCTONARIA. 363same as (i.), but with the tubercles fewer and smaller at largeend.Hab. Port Darwin, N. coast of Australia, 7-12 fms. ; bottom sandand mad.Ohs. A young specimen of what appears to be this species isalmost white (in spirit). Several specimens preserved in spitit andone drj' (the latter probably from the same locality as the rest). Theserrated appearance imparted to the branches by the regularlyuniserial and rigidly lateral arrangement and the prominence of theverrucas is the most striking external point distinguishing thisfrom other species of the genus. In spiculation, as in the externalcharacters of most young specimens, it approaches A. (IJopsella)japonica, but has the tubercles of the large ends of the corticalfusiform spicules much less prominent, the spicules on the wholesmaller than in that species, in which, moreover, the small corticalspicule is elongate, and has the whorls of tubercles at some distanceapart. Older specimens much resemble Mopsella textifonnis in theproportions and arrangement of the branches :but the tint incliningto crimson rather than to scarlet and the strictly marginal positionon them of most of the verrucse serve to distinguish A, serratasuperlicially. The specimens are mostly more or less imperfectthe tallest measures 80 millim. in height.PSILACABARIA *, g. n.Melithseidae without foliate spicules (Blattkeulen) ; branchesgiven off from soft joints at approximately right angles ; spiculesfusiform, the tubercles of the large cortical spicules tending tocoalesce into ring-like ridges ; verrucas spirally arranged.This genus is at once distinguished by the wide angles formed bythe branches ; those of other species of MelithEeidie rarely, if ever,exceed 45°. The arrangement of the branches and of the verrucseupon them is less bilaterally symmetrical than in any other Melithteidexcept Clathraria rubrinodis, Gray {Mopsella hicolor, Ivolliker)hence, perhaps, this is an older form, allied to the Coralliidfe or toother Alcyonaria with imperfect bilateral symmetry. The ridge-liketuberculation of the larger cortical spicule is not elsewhere found,though the smaller cortical spicule oi Mclkodes ochracea has two similarbut usually continuous ring-like ridges. These spicules are unusuallylarge in the single species assigned to this genus ; in it, too, thebranches are remarkably slender and the intcrnodes relatively verylong ; their pure white colour is a iinique character among normaladult specimens of known Melithseaceae ; although in the rare generaTrinella and P((risis, which appear to me to be best ranked in thisfamily, as representing a distinct subfamily, the white colour reappears.This, however, is perhaps of superficial importance. Inall other respects it agrees with Acabaria, Gray.* From »//(X6s, slender, and Acabaria a genus of Melithaeidse (derivation"Accabaar," Malay name of Melitodes ochracea).