with descriptions of new Species. 341 
though irregular in form, and on account of their crowded state 
the mode of branching scarcely distinguishable, except towards 
the terminal twigs, which are linear, very minute and irregularly 
bifurcated : papille small, numerous, and passing through the 
surface of the matrix without apparent order, though pretty 
equally distributed and closely set; towards the margin of the 
sponge they occasionally run in lines. Spicula rather stout and 
short, being ;}5th of an inch in length, somewhat suddenly bent 
im the centre, with one end generally a little enlarged and rounded, 
the other tapering gradually to a sharp point. There is also 
another kind of spicula which appear to be more numerous than 
those just described, but not quite so long; these are sharply 
pointed at each end, and suddenly bent in the centre where they 
are thickest ; at. this point, too, there is frequently a decided no- 
dule, and occasionally two or three. 
_ Only one specimen of this species has been obtained ; it is in 
the shell of Ostrea Canadensis. In general appearance this 
sponge has considerable resemblance to C. lobata; the lobes, 
however, are rounder and smaller, and the spicula at once distin- 
guish it from that species, and from all others with which I 
am acquainted. 
The puncturing in the sides of the excavations of C. Cana- 
iti is minute and somewhat obscure, and less regular than 
usual. 
C. millepunctata. Pl. XII. fig. 9. 
Sponge composed of an intricate interlacement of minute 
branches not more than ,},th of an inch thick, being throughout 
made up of close-set, irregularly rounded lobes, except towards 
their terminations, where they are linear and much less crowded : 
papille minute, close-set, and exceedingly numerous: spicula 
z4oth of an inch long, linear, very slender, frequently much and 
abruptly bent in the centre, sometimes more gradually arched 
towards one end which is sharply pointed ; the other termination 
is furnished with a large elliptical head. 
I have seen only one example of this distinct species ; it is in 
the shell of Cassis tuberosa, and spreads almost entirely over it ; 
the surface is crowded with the minute papillary orifices, and on 
rubbing a little of it away the substance beneath is found to be 
completely riddled with the sponge, and to present a pretty re- 
gularly punctured appearance caused by the chambers occupied 
by the lobes. The principal branches, however, can be distinctly 
traced ramifying in various directions. 
C. lobaia. Pl. XII. figs. 4 & 8. 
: 
Sponge branched, anastomosing ; the branches composed of a 
series of comparatively large, rounded, somewhat transversely 
