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Show 1877.] FIVE N E W SPECIES O F S P O N G E S . 457 Colour, in the dried state, nut-brown. Hab. Kordo, Island of Mysore, Geelvinks Bay, N e w Guinea (Dr. A. B. Meyer). Examined in the dried state. Type in the Dresden Museum. Dr. Meyer observes :-" In life, of the gayest green, red, and yellow colours, which fade away very quickly. The form of this sponge is that of a single long fistulous body which has apparently been attached to the side of a mass of calcareous matter by a short stout pedicel, and has then curved upwards to about eight inches in height. Its external diameter rather exceeds two inches ; and its internal one averages one and a half inch. Externally it is very rugged and prominently tuberculous, while its inner surface is smooth and even, with numerous dispersed oscula for discharging their effete streams into the large cloacal cavity, which exceeds seven inches in depth. The oscula within the great cloacal cavity are numerous, and appear to be equally distributed throughout the whole of its length ; they rarely exceed a line in diameter. The external surface of the sponge abounds in porous cavities or depressions ; but the true inhalant pores of the dermal membrane that lines them are inconspicuous, and I did not detect a single open one on any part of the dermal membrane when mounted in Canada balsam. The dermal membrane is abundantly spiculous. The ten-sion- spicula are acuate, stout and long, and as large as those of the skeleton; they are dispersed or sub fasciculated ; occasionally, but rarely, a few of the attenuato-acuate internal defensive spicula occur among them ; but I could not detect any acerate spicula. The bidentate equianchorate retentive spicula are very slender and minute, their denticuli are long and obtusely terminated ; they vary greatly in size, the smallest ones frequently not exceeding half the size of the larger ones. The largest I found measured y s W inch in length ; of the smaller ones, one measured -^iTn ^nc^> a n d another 3 ^ u inch in length. The fibre of the dermal rete is not so abundantly spiculous as that of the skeleton. The latter frequently assumes quite the appearance of a Desmacidon from the abundance of its spicula. The skeleton-spicula are of two forms, acuate and acerate, the latter form being of rather rare occurrence ; both forms are rather variable in length : they are very numerous and closely packed in the fibres ; their average length is y^y inch. The internal defensive spicula are based on the surface of the skeleton- fibre, from which they are projected at various angles. Their bases aud the distal halves of their shafts are abundantly spinous, the proximal half of the shaft being frequently destitute of spines; these organs are well developed and are all acutely conical. The internal defensive spicula are very numerous, and they form a most effective defence against any minute Annelids that might attempt to enter the skelton structures of the sponge. Their average length is TirTo hien cinn*t erstitial membranes closely resemble the dermal one, but |