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

620 COLLECTIONS FROM THE WESTERN INDIAN OCEAN.or sarcodic material, and a single form of spicule, viz. smoothacuate of considerable lougth, and by the presence of a regulardermal skeleton composed of spicules laid horizontally. I do notknow any other species except the original one, L. massalis, Carter,and the two described below.42. LeucopMceus proteus. (Plate LIII. fig. B ; Plate LIV,fig. A-.)Massive, suberect ; irregularly columnar near base, showing a tendencyto terminate above in several short and thin membranous orprismatic lobes, which by anastomosis inter se enclose cellular spaces,within which the chief excretory canals open. Surface very variablein character in different specimens ; either rough or even andglabrous near the base, towards apex longitudinally ridged andgrooved, leading up into the membranous expansions just described,and hispid with closely set, upwardly-directed sharp points, 1-2millim. high, tending to coalesce into ridges, and terminated bysingle projecting spicules. Vents opening either upwards at thebottom of the spaces enclosed between the terminal lobes, orlaterally between the larger lateral ridges, 1-3 millim. in diameter.Consistence in spirit—that of solid basal part firm, rather elastic,that of upper laciniate parts compressible, elastic ; colour, surfacereddish purple, interior dull palo brown. Main skeleton formed ofvery loose spicular tracts, 5-10 spicules broad, passing outwards fromthe centre of the sponge, at distances of about -28 to '6 millim. fromeach other, branching at acute angles, but maintaining a directionsubparallel to each other, and not crossing. No visible hornyuniting substance ; spicules connected by a yellowish sarcode,rather darker than the interstitial sarcode. The terminal spiculesof the fibres either penetrate or support the dermal membrane.Dermal skeleton consisting of irregular tracts of spicules laid obliquelyor vertically along the ends of the main-skeleton fibres. Sarcodesubtransparent, yellowish brown in centre, bright reddish purple atsurface. Spicules smooth acuate, bluntly rounded at base andtapering gradually to sharp points from about the middle ; size about2-5 by -032 millim.Hal. Providence Reef, Mascarene group, 24 fms. ; bottom, sandand dead coral.Of the two spirit-specimens from which this description is drawnup, the largest has the variable surface characters above described,and must have been 50 millim. (2 inches) high by 25 millim.broad when perfect ; its basal portion is very irregularly formed,being curved to one side and ending in a cup-shaped depression, bywhich it was perhaps attached to a shell or other foreign body :the smaller specimen has lost its base. The specific name, proteus,is intended to commemorate the variability of the outward form.The general habit is that of L. massalis and fenestratHS ; but thespicules diff'er from those of the former in being about five times as