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

G;8P0NGIIDA. 429longer than broad, inner margins truncate, as seen from front,tubercle distinct; shaft slightly and gradually curved; size -01millim. long : abundant, especially in dermal membraue. (4) Tricurvate,smooth, strong, the curves bold, the points sharp ; size -15by "OuG millim.Hah. Prince of Wales Channel, Torres Straits, 7 fms. ; bottomsand.A specimen and a fragment in spirit, the former SO millim.broad by 75 high by 40 thick at present base ; it is almost semicircularin outline, the round margin uppermost ; it appears to havebeen torn from a rather larger specimen.The presence of a tibiella with smooth ends distinguishes it fromall allied species of Desmacidon (Schmidt) but D. emj^hysema, Schmidt(JB. Comm. Unters. deutsch. Meer. ii.-iii. p. 118), and B. physa (id./. c), the latter of which, however, has the surface of the spongeeven and the sponge itself flask-shaped ; in the former the sponge iscovered with bubble-like elevations. Desmacidon arciferum, Schmidt,which has a similar tibiella, appears to be an OphJitisponijia, fromthe strong horny fibre and the echinating arrangement of some ofits acuates. D. diance, id., has, besides, the tridentate anchoratcs ofMl/.villa and a strongly horny fibre ; and both it and B. anceps,id., possess the forcipiform spicules which occur in Haliclwndriaforcij.ns, Bk.64. Ampliilectus hispidulus.(Plate XL. tig. C ; Plate XLI. tigs, y-y".)Erect, clathrous ; formed of a number of irregularly branchingand anastomosing masses, their surface more or less covered withlow cylindrical or ridge-like elevations. Vents ? Surface hispid withclosely set, hair-like terminations of the primary skeleton-fibres.Texture of sponge in dry state firm, elastic, but readily torn, inspirit soft, elastic ; colour dull pale brown in dry state, in spiritpale pinkish brown.Main skeleton of the type known as " isodictyal," viz. consistingof primary lines running straight to the surface, at right angles toit, connected by numerous transverse secondary lines set at rightangles to the piimaries; distance between primaries at surfaceabout "25 millim., between secondaries '17 millim., length of thesurface processes of primaries about -3 millim. Fibres formed ofpale yellow horny material, cored by the axial spicules (no. 1) tothe extent of about one third of their total thickness in the case ofthe secondary fibres, about three quarters in the primaries ; marginsof horny material clearly seen outside the spicules, except in thesurface-tufts of the primaries, which arc opaque and dark-colouredspicules in series of 3. or 4 in the primary, of 2 in the secondaryfibres, of about 6 in the dermal tufts of the primaries. Dermalskeleton consisting of an irregular reticulation with polygonalmeshes made up of fibres, some of which resemble the primaries,