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On a New Sponge, Teteyopsis columxifer. By C, 

 Stewart, Esq., F.L.S., Curator of St. Thomas's Hospital 

 INIuseum, with Plate XVIII. 



For the opportunity of examining and describing this 

 interesting sponge I am indebted to the kindness of my 

 friend Prof. W. H. Flower, of the Royal College of Surgeons. 



I found it in a jar containing marine animals collected on 

 the coast of the Philippine Islands by the late Mr. Cuming ; 

 in the absence of further evidence this may be taken as its 

 probable habitat. 



The sponge consists of an irregular hemispherical basal 

 portion, a little less than an ineh-and-a-half in diameter, 

 thickly incrusted with pieces of shells and small stones ; its 

 flat surface has either been torn off from a rock or from a 

 continuation of its substance completing the sphere ; tin's 

 surface shows long spicula radiating from the centre imbed- 

 ded in firm sarcode, and supporting on their distal extremities 

 a white superficial layer, usually about the fortieth of an inch 

 thick, but frequently greatly increased as the interstices be- 

 tween the extraneous substances are filled by it; the torn 

 orifices of four canals may also be seen. 



From the convex surface of this, the basal portion, arises a 

 stem-like prolongation three-tenths of an inch in diameter 

 and one inch and two-thirds in length, it is free from any 

 foreign particles except a few small grains of sand at its 

 extremity, but is roughened by numerous elevations of the 

 dermal membrane arranged in a right-handed spiral of half a 

 turn, Avhich is not always strongly marked. 



On section it shows a dense axis of spicula occupying a 

 third of its diameter, from which laterally flattened processes 

 extend to support the dermal membrane, which is raised by 

 them into the elevations already alluded to; the very large 

 intermarginal cavities thus formed communicate freely throu^li- 

 out the entire stem, and with the canals of the basal portion 

 of the sponge. 



The large spicula of the basal mass are of the form termed 

 " expando-ternate" by Dr. Bowerbank ; the long shaft of the 

 spicula reaches from the dermal membrane to near or quite 

 to the centre of the sponge, where it terminates in a sharp 

 point, its ternate distal extremity supporting the dermal 

 membrane; mixed with these are a few of the same size but 

 pointed at both ends. The sarcude spicula are stellate and 

 about the 1200th of an inch in diameter. The dermal mem- 



