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

:SPONGIIUA. 43770. Esperia pellucida.(Plate XL. fig. K ; Plate XLII. fig. h.)Growth horizontal, spreading over and between stones &c., risingat certain points into slender lobes. Surface even, glabrous. Consistencerather firm and brittle. Vents? Colour in spirit palepink or dirty white, subtransparent. Dermal membrane gelatinous,transparent, subelastic, firm ; internal structures soft. Mainskeleton formed of delicate, widely inosculating fibres 4 to 6 spiculesbroad, soft, branching at obtuse angles. Dermal skeletonconsisting of angular meshes formed by distinct straight tracts ofspicules, 2 to 4 spicules broad.SjHCules :—(1) Skeleton subspinulate ; straight or slightly curved ;head marked by a slight and gradual enlargement a little belowbase ; head round and blunt, diameter less than maximum diameterof shaft : shaft tapering gradually to sharp point from within about2 to 6 diameters of apex ; size -42 by -0095 millim. (2) Largeinequianchorate ; shaft strong, slightly bent, of same diameterthroughout except near the two ends. Large end forming aboutone third of total length of spicule, diameter about the same as itslength. Lateral palms, as seen from front, broad, truncate below,inferior angle projecting slightly ;outer margin slightly revertedthroughout ; median ])a!m oval, small ; tubercle distinct, small,pear-shaped ; small end almost truncate above as seen from front,but with the supero-lateral angles sharp, slightly produced upwards,outer margins reverted throughout ; tubercle relatively large, anvilshaped; the small end of the s]iicule is truncate below and abouthalf the diameter of the large end ; length of spicule '1 millim,(3) Small inequianchorate ; shaft slender, gradually curved ; largeend forming about two fifths of total length of spicule ; lateral palmswith sharp inferior angles, being excavated on inner side, outermargin reverted throughout; tubercle narrow, elongate; smaller endabout half the length of upper (larger) end ; outer margin revertedthroughout ; tviberele subterminal, s(|uarish ; end truncate belowlength of spicule -032 millim. (4) Bihamate, contort, slender, withwide curve , size 'Go? by '0032 millim. (5) Trichites, in bundlesof from 20 to 30, with tine points ; size of individual spicules -06by -0015 minim.Hah. Alert Island, Torres Straits, 7 fms. ; bottom sand.The anchorate of this spicule belongs to the more common of thetypes occurring in Atlantic and Mediterranean Esperia' ; it is, however,larger than most, if not all, and the presence of a second formof inequianchorate is another unusual point. The single specimenis in spirit and runs over and between a number of lor so andattached calcareous fragments, i. e. shells &c. The upright lobes areabout 16 millim. long and somewhat flattened.