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VII. Description of a new Genus and Species of Sponge (Euplectella ' Aspergillum, 0.). 

 By Richard Owen, F.R.S., F.Z.S., S^c. &!c. 



Communicated January 26, 1841. 



jyj.R. CUMING has entrusted to me for description one of the most singular and beau- 

 tiful, as well as the rarest, of the marine productions with which his researches in the 

 PhiUppine Islands have enabled him to enrich the zoological collections of his native 

 country. This production forms part, however, of a member of the lowest class of or- 

 ganized bodies, being the skeleton or framework of a species of Sponge, belonging to 

 the cylindrical and reticulate, or 'Alcyonoid' family. It is a hollow, subcircular, 

 slightly conical, and gently curved case or tube, resembling a delicate cornucopia with 

 the apex removed. It measures eight inches in length, two inches across the base, 

 and one inch and a quarter across the apex, which is truncated. The base or wider 

 aperture of the tube is subelliptical, and is closed by a cap of coarse and somewhat 

 irregular network, gently convex externally, the circumference of which is divided 

 from the walls of the cylinder, like the base of the Aspergillum or water-pot shell, by a 

 thin projecting plate, standing out like a ruff or frill. This marginal plate varies in 

 breadth from one to three lines. The parietes of the circular cone consist also of a 

 network of coarse fibres, but these exhibit great regularity of disposition, and in- 

 tersect each other at definite and nearly equal distances throughout the course of the 

 cone : they consist of longitudinal, transverse, and obhque fibres, the latter being of two 

 kinds, winding spirally round the cylinder, but in opposite directions. The strongest 

 fibres are longitudinal and transverse ; they are arranged at intervals of about a line 

 and a half, and mark out square spaces of the same diameter : these spaces are kept 

 of pretty equal size throughout the cone, from the circumstance of the longitudinal 

 fibres diminishing in number as the cone decreases in size : the mode of diminution is 

 not, however, by abrupt termination, but by the gradual convergence and final inter- 

 blending of two contiguous longitudinal fibres, and the regularity of the interspaces 

 is therefore disturbed at the intervals of such converging fibres. The fibre resulting 

 from this union of two fibres bears a proportionate thickness to the additional material 

 entering into its composition : the nature of such material is demonstrated at the apex 

 of the cone by the resolution of the longitudinal fibres into their component filaments, 

 each fibre dividing at about two-thirds of an inch from their extremity into a fasciculus 

 or pencil of extremely delicate, rather stiff, glistening, elastic threads. The transverse 



' Der. ev, well, TrXekw, / toeave. 



