Sponge- Spicule in its Mother Cell. 457 



rately noticed in detail, there would be no difference be- 

 tween the two whatever. The tricurvate in the adult of this 

 sponge is at once recognized by its form (fig. 27, a), while the 

 nucleated cell (fig. 27, b) which encloses it, corresponding with 

 its extreme length, presents the same bolster-like appearance 

 or tubular form as that in the variety of Esperia cvgagropila 

 just mentioned. 



As this sponge appears to me to be Microciona armata of 

 Dr. Bowerbank, I shall describe it under this appellation. 



Microciona armata, Bk. (?). 



General form incrusting, thin, spreading indefinitely. Ses- 

 sile, flat. Colour sponge-yellow or scarlet. Structure con- 

 sisting of short, erect, scopuliform bundles of spicules in juxta- 

 position, imbedded in sarcode and based on a minutely reticu- 

 lated horny membrane. Spicules of two kinds, viz. skeleton- 

 and flesh-spicules. Skeleton-spicules of three forms, viz. : — 

 1st, the largest and longest, curved, acuate, smooth, except at 

 the large end, which is round and spined ; average largest size 

 45 by 1-1 800th in its greatest diameters : 2nd, sub-pinlike, 

 nearly straight, acuate, smooth throughout except at the inflated 

 end, which may bear one or two minute spines ; size variable, 

 from 10 to 30 by \-l 800th inch in its greatest diameters (? in- 

 cipient forms of the foregoing spicule) : 3rd, the smallest, short, 

 acuate, straight, more or less spined throughout or to within 

 a short distance of the point. All these spicules have their 

 large ends fixed in the scopuliform bundle. Flesh-spicules of 

 two forms, viz. : — 1st, tricurvate (fig. 27, a), abruptly bent 

 into a subtriangular form in the centre, with the arms ex- 

 tended in a more or less straight line on each side, ending in 

 pointed extremities which are spined (fig. 27, d) • average 

 longest forms 30-1800ths inch in length : 2nd, equianchorate, 

 minute, navicular or weaver's-shuttle-like in form, l-1800th 

 inch long ; these are scattered throughout the sarcode in 

 which the scopuliform bundles are imbedded. General size 

 of species about a line in thickness and of indefinite extent. 



Hob. Marine, on rocks of the New B,ed Sandstone conglo- 

 merate. 



Loc. Budleigh-Salterton, south coast of Devon. 



Obs. This seems to me, as before stated, to be Dr. Bower- 

 bank's Microciona armata ; and if so, his description is so im- 

 perfect that the above will be found absolutely necessary be- 

 fore it can be identified. The characters mentioned easily 

 distinguish it from Microciona atrosanguinea, Bk., whose 

 colour, although sometimes also sponge-yellow, is crimson or 

 dark blood-red and not " scarlet " or bright red. 



