272 
THE VOYAGE OF H.M.S. CHALLENGER. 
Colour. — Purplish-red, or white. 
Habitat. — Borneo (Gray) ; Gulf of Manaar (Carter). 
Remarks. — 0. Schmidt describes sponges, which he refers to this species, from 
Florida, on coral reefs, at 30 to 60 fathoms. Type-slides are in the British Museum ; 
these and the general structure of the sponge, as figured by Schmidt, show that if not 
identical, it is a very closely allied form ; still I could not find the minute spherules 
so characteristic of the species, and it is possible that Schmidt’s sponge should be referred 
to the new species, Placospongia intermedia [vide p. 273). 
Carter’s illustrations of the spicules of Placospongia melobesioides do not appear to 
be taken from new material, but from Gray’s sponge ; amongst them, however, is one of 
a small spiraster which I have not been able to find. 
Placospongia carinata (Bowerbank) (PI. XL. fig. 7). 
Geodia carinata, Bowerbank, sp. MS., Phil. Trans. Roy. Soc., pp. 308, 314, pi. xxvi. fig. 10; 
pi. XXV. fig. 19, 1858. 
„ ,, Bowerbank, Mon. Brit. Spong., voL i. p. 254, pL x. fig. 163, 1864. 
„ „ Bowerbank, Proc. Zool. Soc. Lond., p. 298, pi. xlvL figs. 1-5, 1874. 
„ „ Bowerbank, Proc. Zool. Soc. Lond., p. 295. 1875. 
Placospongia carinata, Ridley, Spong. “Alert,” p. 481, 1884. 
Sponge. — Sessile, coating stems of Gorgonia or Fuci (Bowerbank), or massive 
branched. Surface smooth, with numerous longitudinal carinse. Oscules simple, few, 
dispersed. Cortex 0'56 mm. in thickness, consisting chiefly of the sterrastral layer ; 
beneath the external epithelium a layer of microstrongyles. The cortex is divided into 
plate-like pieces, having the edges bevelled on the inside, separated by longitudinal 
grooves, and united by transverse muscular masses, which are attached to the bevelled 
edges. The pores are probably situated in the grooves, and lead into canals which run 
radially through the muscular bands into the choanosome. The walls of the canals are 
lined by longitudinally disposed microstrongyles. 
In the centre of the choanosome is a dense sterrastral axis, and numerous sterrasters 
are also scattered through the tissues between the axis and the cortex. The tylo- 
styles are arranged side by side, with the strongylate ends diverted outwards in 
dense spicular bundles, which radiate from the sterrastral axis and towards the bevelled 
margins of the cortical plates and the sides of the poral grooves. Some of the spicules 
of these bundles traverse the muscular bands, and project on each side of the poral 
grooves. 
Large spirasters (No. 3) occur within the choanosome, chiefly in the muscular tissue. 
Spicules. — I. Megasclere. 1. Tylostyle, actine cylindroconic, usually strongylate. 
