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|^th 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. lohata) 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- 

 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 y\jth 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 : 

 papillae minute, close-set, and exceedingly numerous : spicula 

 j^^th 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 tubei'osa, 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. lobata. PI. XII. figs. 4 & 8. 



Sponge branched, anastomosing ; the branches composed of a 

 scries of comparatively large, rounded, somewhat transversely 



