120 Mr. H. J. Carter on the Genus Rossella. 
a specific distinction, any more than the same complement of 
spicules is always accompanied by the same form of sponge: 
thus, two sponges may be almost undistinguishable in their 
general forms, and yet, after all, be totally different in the 
forms of their spicules respectively. Hence the necessity of 
examining every specimen of sponge microscopically before we 
decide on its specific characters. 
As in hk. antaretica, so here we have younger specimens of 
R. philippensis (fig. 2) growing upon the hair-hke locks of 
the older ones (fig. 1, f), but much larger in dimensions, 
similar to those noticed in the concluding part of my descrip- 
tion, which suggested to Dr. Gray the name of “Psetalia glo- 
bulosa”’ (2. c.). But whether originating in ova or pullulation 
I am, as above stated with reference to the minute ones on 
R. antarctica, unable to determine. 
Lastly, it might be observed generally that although the 
hooked extremities of the anchoring-spicules have been for 
the most part torn off, there are many among them, especially 
coming from the upper part of the sponge, which naturally 
have never had any, but have always been fine-pointed. 
Rossella velata, Wyville Thomson (‘ The Depths of the Sea,’ 
p: 418). 
General form oveid, hollow ; truncate and open at the upper, 
closed at the lower end. Aperture subcireular, slightly widen- 
ing inwards from a thin margin to a cavity of much the same 
shape as the sponge itself externally. Sessile or fixed by 
anchoring-spicules. Colour brownish grey. External surface 
uniformly net-like and monticular, resting on a widely cancel- 
lated structure below, and covered by the latticework spicular 
layer above, which is again surmounted by three forms of 
appendicular spicules, whose relative positions and forms will 
be described hereafter. Internal surface or that of the cavity, 
the structure of the body or wall, and that of the latticework 
layer the same as in both the foregoing species. Pores and 
vents respectively the same in form and situation. Monticules 
of the surface round or boss-like, looking like so many stelliform 
emmences regularly linked together by interradiating lines. 
Spicules of three kinds, viz. appendicular, structural, and 
flesh-spicules. A. Appendicular of three forms, viz. 1, pointed 
at each extremity, and 2, four-hooked at the free end (like 
nos. 1 and 2 in R&R. antarctica respectively), associated, scantily 
scattered over the upper part of the body im small groups issu- 
ing from the summits of the boss-lke eminences, becoming 
more numerous towards the lower part, where they attain 
~*~ 
