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

ALCTONARIA. 339present species. In habit these three species are closely similar.A specimen in the Museum, which is appareutlj^ the type of Bovellaramulosa, (jtray (Aun. & Mag. jSTat. Hist. (4) v. p. 407), is closelyallied to E. Jiabcllum, and should stand as EcJiinogorr/ia ramulosa,EuNICEACEiE.13. Plexaura praelonga, sp. n., var. typica. (Plate XXXVI. fig. F,and Plate XXXVIII. figs, r/, g'.)Common stem ex-Growth upright, approximately in one plane.tremely short. Branching dichotomous ; branches few, almoststraight : terminal branches 150 millim. (6 inches) and upwards inlength in adult specimens. Stem and branches cylindrical, eithernearly of the same diameter throughout in both cases, viz. about2-5 millim., or ranging from 6 millim. at base to 3 millim. at end ofbranches in adult specimens. Cortex approximately smooth, even,rather friable. Colour in dry state pale red-brown or dark tawnybrown. Verrucse small, not projecting from surface, equally distributedover all parts, 5 to 1 millim. apart. Axis tough, flexible,black. Cortical spicules :—(i.) Long fusiform, aj^proximately straight,tapering to sharp points, with few, scattered, tapering, sharp, simpletubercles ; size about -35 by -07 millim. (ii.) Stout fusiform-cylindrical,covered with low, blunt, compound tubercles ; size about -3 by1 millim. (iii.) Irregular tri- to sexradiate, arms cjlindrical, taperingto sharp points, with numerous but distinct, prominent, simpleor compound, pointed tubercles ; maximum diameter of spicule -25to -52 millim., thickness of arms '042 to -1 millim. (iv.) Blattkeule ;shaft with one or two distinct arms uniting in a moderately stoutneck, often themselves bearing secondary arms ; the whole shaft iscovered densely with very prominent, tapering, compound tubercles.Foliar portion flattened in one plane, variable, cither approximately oblongwith rounded angles, or much drawn out latei'ally, forming anglesat tliis point, and with a point below, or with the lower edge brokenup into small lobes ; edges sharp, aiinutely scalloped. From theshaft descend on to the foliar portion, sometimes more than halfwaydown its face, one or more narrow, more or less prominent ridges,tajiering so as gradually to disappear ; or the place of each ridge istaken by one or more rounded prominences ; both ridges and prominencesare smooth ; length of spicule about "5 millim., breadth ofBlatt -3 millim.Hah. Port Curtis, 5-11 fms., bottom sand and shells ; Port Denison,4 fms., bottom rock.Obs. Two dry specimens, the one from which the larger externalmeasurements were taken being largely decorticated, occur, alsoPlexaura ma}- be open to doubt ; in its spiciiliitiou it agrees with Plexaurella aslimited by Verrill (Proc. Ess. Inst. vi. p. 42) ; but L)r. Khinzinger does notstate explicitly whether the axis is simply horny or wlidher it contains tliecarbonate of lime, by the presence of wliich Kolliker distinguishes the genusfrom Plexaura.z2