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

—'438 COLLECTIONS FROM MELANESIA,71. Esperia obscura,? Carter, Ann. ^ Mag. Nat. Hist. 1882, ix. p. 299, pi. xi. fifj. 18.? Mycale grandis. Gray, P. Z. S. 18157, p. 58.3 = " Eine indische Esperie,"Schmidt, Suppl. Spong. Adr. Meer. p. 34, pi. iii. fig. 11.Mr. Carter assigned the above name to a massive specimen fromFreemantle, S.W. Australia, of which he says (l. c.) it has " all thecharacters of Esperia, viz. lace-like dermal layer, rigid interior fibre,and acuate (sub-pinlike) form of skeletal spicule, but with an ineijuianchoratcabout 5-OOOUths " (of an inch) " long so transparent inits detail that all I can give of it are the representations (pi. xi.fig. 18), in the hope that it might be thus recognized and finallyillustrated." In the present collection made by H.M.8. ' Alertoccur two small imperfect specimens of an Esperia which has (besidesa larger one) a small inequianchorate spicule which strongly resemblesMr. Carter's figures above referred to, and does not contradict inany point the other parts of the short description which was allthat Mr. Cai'ter was able to give of his species. I therefore proposeto refer the present specimens to that species provisionallyuntil other specimens are obtained from Freemantle or its neighbourhoodwhich may clear up the question of identity. The followingis a description of the ' Alert ' species ;it may be taken as characteristic,so far as the more minute characters go, the tissues beingin a good state of preservation :Sponge massive, enclosing detached (and perhaps fixed) foreignbodies. Texture firm, rather brittle. Surface gently undulating,glabrous. Vents numerous, oval, 1 to 2*5 millim. in greatest diameter,scattered on general surface ; margins thin, sometimes projectingsomewhat ; main excretory canals rising from a distancebelow the surface. Dermal membrane thin, glabrous, semitransparent,firm. Colour in spirit pale dull brown.Main skeleton—spiculo-fibre moderately well defined, delicate,branching at various angles, from 5 to 10 spicules broad. Dermalskeleton diffuse, the spicules scarcely ever arranged into definitetracts, but loosely matted. Sarcode thin, very pale yellow-brown,slightly granular.Spicules: — (1) Skeleton subspinulate, straight or slightly curved,head elongate, subterminal, slight, gradually passing into a bluntlyroundednarrower extremity on the one hand, and into the shaft onthe other ; diameter of head decidedly less than that of shaft ; shafttapering gradually to within about three diameters of apex and thenrapidly to a sharp point; size -8 by •014miUim. (2) Large inequianchorate; shaft slightly curved, stout ; larger end of spicule of samelongitudinal and horizontal diameter, viz. one third as much as totallength of spicule ; lateral palms finely curved, ending below insharp inwardly-curved points and reduced to narrow falciform processeswith a narrow reverted rim as seen from front ; anterior palmoblong, with rounded angles as seen from front ; tubercle distinct,oval ; smaller end of spicule with abrupt square upper margin ;