354 DR. BOWERBANK ON ALCYONCELLTJM SPECIOSUM. [Mar. 28, 



I might make a searching investigation of the pecuharities of its 

 structure. Dr. A. Farre also allowed me the free examination of 

 his specimen, described and figured in the ' Transactions of the Lin- 

 nean Society of London,' vol. xxii. p. 117, pi. 21, as Enplectella 

 cucumer, Owen. I have repeated these investigations on two other 

 specimens in my possession, of nearly the same size and form as 

 that formerly possessed by Mr. Cuming, but now in the British 

 Museum ; and I have found that the structure of their skeletons 

 and the cvirious and beautiful forms of spicula contained in their 

 interstices are perfectly identical even to the minutest form ; so that 

 we may reasonably and safely conclude that there is but one species 

 of this beautiful sponge known to us at present in England, and that 

 it is identical with the species described by MM. Quoy and Gaimard 

 in their 'Zoology of the Voyage of the Astrolabe.' Neither of 

 the above-named authors, nor Prof. Owen in either of his descriptions 

 of the sponge, has given us a detailed statement of its specific cha- 

 racters J I shall therefore proceed to endeavour to rectify this omis- 

 sion as follows : — 



Alcyoncellum SPECIOSUM, Quoy et Gaimard. 



Sponge sessile, cylindrical, more or less curved, enlarging pro- 

 gressively from the basal to the distal extremity ; upper portion fur- 

 nished with numerous sharp ridges of interlacing fibres disposed 

 diagonally and somewhat symmetrically ; a])ex truncate, closed by a 

 coarse, ventricose, fibrous network, and encircled by a strongly pro- 

 duced fibrous ridge or frill. Base furnished with numerous fasciculi 

 of large and long prehensile spicula projected downward : spicula 

 attenuato-quaternate, barbed alternately for about one-third of their 

 length from the distal extremity. Oscula congregated, terminal. 

 Pores congregated ; inhalant apertures symmetrically equidistant, 

 disposed in lines radiating from the base to the apex of the sponge. 

 Dermal membrane unknown. Skeleton symmetrical ; primary 

 lines radiating from the base to the apex, equidistant ; secondary 

 lines at right angles to the primary ones ; interstitial structures inter- 

 lacing diagonally. Spicula of the membranes : — interstitial spicula 

 rectaugulated, attenuated hexradiate spicula, short and stout, rarely 

 completely developed ; and the same form with slender and delicate 

 radii, fully developed ; also attenuated rectaugulated triradiate, api- 

 cally spined. Spicula of the sarcode : — trifurcated attenuato-hexra- 

 diate ; and floricomo-hexradiate, very minute. 



Colour, skeleton very light amber-yellow. 



Hab, Philippine Islands, Island of Bohol, 10 fathoms {Mr. Hugh 

 Cuming) ; Island of Zebu, about 24 fathoms (3/r. R. Geale). 



Examined in the skeleton state. 



The form of the skeleton of the sponge is exceedingly graceful ; 

 it is that of an elongated Cornucopia, composed of a beautiful and 

 regular network of siliceous fibres. It has uo solid base to retain it 

 in an erect position ; but in lieu of this support it is furnished with 

 a vast number of curious and beautiful retentive spicula, each acting 

 the part of a line and grapnel when their recurvo-quaternate heads 



