190 BRITISH SPONGES: 



wards each end, terminating in some acutely, and in others some- 

 what obtusely ; others have their bases elliptical or globular, as 

 in Fig. a, of Plate XIII. Occasionally, but much more rarely, 

 we observe them furnished with numerous spines or tubercles, as 

 represented by Fig. h, and still more rarely they are multiradiate, 

 and of great comparative size, as represented at Fig. c. I 

 could not detect any peculiar form of spiculum in the fleshy 

 substance which fills the interstices of the skeleton, but I ob- 

 served one or two detached spicula imbedded in its substance, 

 of the foi*m represented by Fig. d. This interstitial fleshy 

 matter is of a firm consistence, and has dispersed throughout its 

 substance numerous round or oval bodies varying from the 

 -Q-Q-Qo to the 5q5o °f ^^ 'n\(\\ in diameter ; containing usually 

 one, but sometimes two nucleii. These bodies are nearly uni- 

 form in their colour and general aspect, and present every ap- 

 pearance of being the cytoblasts whence the cellular substance 

 of the animal is derived." 



2. D? PAPILLOSA, cylindrical and tuhidar with a truncate 

 dimpled apex. 



Plate XVI. Fig. 6, 7. 

 Spongia suberia, Johnston in Mag. Nat. Hist. vii. 491, fig. 60. 



Hah. Parasitical on old shells. Scarborough, Mr Bean. 

 Strangford Lough, Wm. Thompson. 



Sponge in the form of a cylindrical pap, from three to six 

 lines in height, and one or two lines in diameter, of a uniform 

 arenaceous colour, smooth, close and compact in texture, tubu- 

 lar, the apex circular, with an obtuse rim, ocellated or depressed 

 in the middle, to which some faint striae converge from the cir- 



cimiference. The sponge is composed of a thin membrane, 



loaded with unequal cubical grains of quartoze sand, arranged 

 without order, but closely packed like a miniature pavement. 



