until descriptions of new Species. 337 



regularly distributed and rather closely set on the surface of the 

 matrix. Spicula of two kinds ; one, mucli the larger, measures 

 T^yth of an inch in length ; it has at one extremity a large 

 rounded head, is straight, and tapers gradually to a sharp point 

 at the other : the smaller spicula are scarcely more than \t\i the 

 length of the former, are rather stout, fusiform, sharp and gra- 

 dually pointed at both ends, and much and suddenly bent in the 

 centre, where they are thickest. 



I have seen only two specimens of this species : they occur 

 in individuals of Fusils antiquus brought from the Haddock 

 grounds by the CuUercoats' fishermen. This may be at once 

 distinguished from C. gorgonioides by the spicula, that species 

 having only one kind, this two : but the form of the larger kind, 

 which is common to both species, is sufficiently distinct ; its head 

 in those of C. Northwnbrica is almost always quite circular and 

 is at the extreme end ; and moreover they are rarely bent, and 

 when so only very slightly. The branches too are indistinctly 

 lobed in this species, but are never so in C gorgonioides, and the 

 papillae are smaller and more numerous. Unfortunately I have 

 not seen the terminal twigs, as the only two specimens procured 

 of this species had entirely overrun the shells they had attacked. 

 In both instances, the shell being dead, the papillae had perforated 

 each surface. 



a Alderi. PL XV. fig. 9. 



Sponge branched, irregularly and widely anastomosing, and 

 strongly lobed ; the lobes for the most part irregularly rounded, 

 frequently ^th of an inch wide, placed close together, and united 

 by a much-constricted stem : terminal twigs very fine, frequently 

 linear for a considerable length, and bifurcating somewhat irre- 

 gularly : papillse small, rather variable in size, the largest about 

 ^\jth of an inch in diameter, placed rather far apart in a single 

 row along the branches on the surface of the matrix ; they appear 

 occasionally to run in lines. Spicula of two sorts ; one yyT-th of 

 an inch long, moderately thick, slightly bent, with a small oval 

 head near one end, and tapering to the other extremity : the 

 second kind is scarcely shorter than the former and has one end 

 truncate, the opposite pointed, and is decidedly bent in the cen- 

 tre. The puncturing of the walls of the chambers is distinctly 

 visible with a low magnifying power. 



This species is named after my friend Mr. Alder, who took 

 several specimens of it in Pectunculus pilosus on the coast of the 

 Isle of Man : as yet it has occurred in no other locality. 



C. corallinoides. PI. XV. figs. 1 & 2. 

 Sponge freely and distinctly branched, slightly anastomosing, 

 and regularly and strongly lobed; the lobes about ^th of an incli 

 Ann. ^ Mag. N. Hist. Ser. 2. Vol. iii. 22 



