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 : papillae 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 y^^jth of an inch in length, somewhat suddenly bent 

 in 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 smallei', 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- 

 densis is minute and somewhat obscure, and less regular than 

 usual. 



C. millepunctata. PI. XII. fig. 9. 



Sponge composed of an intricate interlacement of minute 

 branches not more than ^^^ th of an inch thick, being throughf)ut 

 made up of close-set, irregularly rounded lobes, except towjuds 

 their terminations, where they are linear and much less crowded : 

 papill?e minute, close-set, and exceedingly numerous : s]>icula 

 J f yth 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 ajjpearance caused by the chambers occupied 

 by the lobes. The principal branches, however, can be distinctly 

 traced ramifying in various directions. 



C. lobata. PI. XIL tigs. 4 8z: 8. 



Sponge branched, anastomosing ; the branches composed of a 

 series of comparatively large, rounded, somewhat transversely 



