438 ( MLLECTIO.VS FROM MELANESIA. 



7 1 . Esperia obscura. 



? Carter, Ann. Sf Mar/. Nat. Hist. 1882, ix. p. 299, pi. xi. fig. 18. 

 'i .Mvcalc Liiandis, Gray, P. Z. S. 1867, p. 533=" Eine Lndjsche Es- 

 perie," Schmidt, Suppl. Spong. Adr. Meer. p. 34, pi. iii. tig. 1 1. 



Mr. Carter assigned the above name to a massive specimen from 

 Freemantle, S.W. Australia, of which he says (/. c.) it has "all the 

 characters of Esperia, viz. lace-like dermal layer, rigid interior fibre, 

 and acuate (sub-pinlike) form of skeletal spicule, but with an inequi- 

 anchorate about 5-000Oths " (of an inch) " long so transparent in 

 its 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 finally 

 illustrated.'' In the present collection made by II. M.S. 'Alert' 

 occur two small imperfect specimens of an Esperia which has (besides 

 a larger one) a small incquianehorate spicule which strongly resembles 

 Mr. Carter's figures above referred to, and does not contradict in 

 any point the other parts of the short description which was all 

 that Mr. Carter was able to give of his species. I therefore pro- 

 pose to refer the present specimens to that species provisionally 

 until other specimens are obtained from Freemantle or its neigh- 

 bourhood which may clear up the question of identity. The following 

 is a description of the ' Alert ' species ; it may be taken as charac- 

 teristic, so far as the more minute characters go, the tissues being 

 in a good state of preservation : — 



Sponge massive, enclosing detached (and perhaps fixed) foreign 

 bodies. Texture firm, rather brittle. Surface gently undulating, 

 glabrous. Vents numerous, oval, 1 to 2*5 millim. in greatest dia- 

 meter, scattered on general surface ; margins thin, sometimes pro- 

 jecting somewhat ; main excretory canals rising from a distance 

 below the surface. Dermal membrane thin, glabrous, semitrans- 

 pai'ent, 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. Dermal 

 skeleton diffuse, the spicules scarcely ever arranged into definite 

 tracts, but loosely matted. Sarcode thin, very pale yellow-brown, 

 slightly granular. 



Spicules: — (1) Skeleton subspinulate, straight or slightly curved, 

 head elongate, subterrninal, slight, gradually passing into a bluntly- 

 rounded narrower extremity on the one hand, and into the shaft on 

 the other; diameter of head decidedly less than that of shaft; shaft 

 tapering gradually to within about three diameters of apex and then 

 rapidly to a sharp point; size "8 by -014 millim. (2) Large incqui- 

 anehorate ; shaft slightly curved, stout : larger end of spicule of same 

 longitudinal and horizontal diameter, viz. one third as much as total 

 length of spicule ; lateral palms finely curved, ending below in 

 sharp inwardly-curved points and reduced to narrow falciform pro- 

 cesses with a narrow reverted rim as seen from front; anterior palm 

 oblong, with rounded angles as seen from front ; tubercle distinct, 

 oval ; smaller end of spicule with abrupt square upper margin : 



