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Show 460 DR. J. s. B O W E R B A N K O N [June 5, both series abundantly laden with externally adherent particles of extraneous matters. Colour. In the dried state, light ochreous yellow. Hab. 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 brown." The form of this sponge is that of a contorted fan six inches high by eight and a quarter inches broad. It is based on a short massive pedicel. The thickness of the general expansion of the sponge does not at any part exceed one twelfth of an inch ; and the general construction of the skeleton is visible to the unassisted eye. It has lost a great part of its dermal membrane j but considerable portions of it still remain. It is destitute of any spicula usually characteristic of dermal tissues; but it is abundantly supplied by adhesion with adventitious spicula of other spoDges and of grains of sand and other such matters. The oscula are scarcely distinguishable ; they appear to consist of minute orifices rarely exceeding the size of one of the areas of the skeleton-rete, and they are very irregularly distributed over the inner or concave surface of the contorted sponge. I could not detect auy pores in a portion of the dermis mounted in Canada balsam. The loosely constructed polyfibrous lines of the skeleton are very singular in their structure. They consist of numerous minute fibres, running nearly parallel to each other, and anastomosing at irregular intervals by short connecting fibres at nearly right angles to each other. Neither the primary nor the secondary lines ever appear to be in any degree twisted. The primary lines, on an average, measured -gl T inch in diameter, and the minute fibres of which they are composed varied frem ^T^ to y ^ j inch in diameter. The interior of the sponge appears to be as abundantly supplied with adherent grains of sand aud other adventitious substances as the dermal membrane is ; but none of such substances were embedded in the keratose fibres of the sponge as in the genera Halispongia or Dysidea. 4. HALISPONGIA STELLIFERA, sp. nov. 4. Sponge cup-shaped, compressed, parietes thin, pedicel short. Surface even and smooth. Oscula small, slightly raised on low tumid elevations, few in number. Dermal membrane pellucid, aspiculous, but abundantly supplied with adherent extraneous matters. Pores disposed in areas containing from one to two or three of them, each surrounded by numerous minute radiating fibres anastomosing near the pore, but diverging separately towards their distal terminations. Skeleton : Primary lines radiating in nearly parallel lines from the base to the distal margin; secondary lines anastomosing irregularly with the primary ones. Primary and secondary lines both polyfibrous; fibres solid, cylindrical, frequently anastomosing irregularly. Gemmules minute, spherical, dark and opaque. |