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

SPONGnDA. 417point of attachment ; the length (horizontal) is 39 millim. (1^ inch),greatest (vertical) thickness 8 millim., average thickness of narrowlobe 2 millim. Colour (in spirit) white ; texture rather firm, harsh(Carter says " tender "). A small aperture, about -3 millim. in diameter,at the end of the shorter lobe is the only perceptible vent.Surface obscurely wrinkled. Spicules as in yi. panicea^ measuring•8 to 1 millim. by -012 to -018 millim.This specimen agrees well in size and in its general and spicularcharacters with those described by Mr. Carter from Ceylon.Hah. Prince of Wales Channel, Torres Straits, 5-7 fms.Distribution. Basse Rocks, Ceylon, Kerguelen Island (Carter),(Atlantic ?, Carter, I. c).53. Tedania digitata, varr.Reniera digitata, Schmidt, Adr. Meer. p. 7o, pi. vii. fig. 11.Reniera ambigua, id. Adr. Meer. Suppl. p. 39, pi. iv. fig. 8.Reuiera muggiana, id. Spontj. Akf. p. 28.Tedania digitata et muggiaua. Gray, P. Z. S. 1867, p. 520.Tedania nigrescens, Schmidt, Adr. Meer. p. 74, is probably notdistinct from the above species ; but, as it was not intelligibly describeduntil after T. digitata, the latter name in any case takesprecedence.From a comparison of the specimens and slides of these differentspecies in the Museum infer se and with Schmidt's descriptions, Icome to very much the same conclusion as Schmidt (Atl. Geb. p. 43),viz. that they are all mere varieties. Schmidt's expression is thatit is merely a matter of taste whether thej' are called species orvarieties. The differences in outward form have caused him hisgreatest doubts as to their identity ;and it is true that, while somespecimens bear large lobate elevations, others are massive, andthat whereas some have large vents, in others they are all smalland scattered. But I find that all agree in a more or less massivehabit, cavernous structure, and strongly ridged or papillose surface;whereas the Atlantic form, T. suctoria, Schmidt, and the ChilianT. tenuicajntata , mihi, have an almost even surface.The forms of the spicules are practically the same in all cases, andthe micro-spination of the heads of the cylindrical " tibiella " isundoubted throughout, whereas in the two specified species the headsare quite smooth.The Port-Darwin specimens differ decidedly in the proportions ofthe acuato spicule, as will be seen below, from the rest. None ofthe varieties pointed out seem to stand out with sufficient distinctnessfrom the rest to receive distinct varietal names. A specimen latelyreceived from Kurrachee agrees essentially with all the above specimens,the spicules being only rather stnall ; the surface is brokenup into a dense mass of slender, almost filiform processes andlamellar ridges, from 1 to 5 or 6 millim. high.