with descriptions of new Species. — 337 
regularly distributed and rather closely set on the surface of the 
matrix. Spicula of two kinds ; one, much the larger, measures 
7yth 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 jth 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 Fusus antiquus brought from the Haddock 
grounds by the Cullercoats’ 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. Northumbrica 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. goryontoides, and the 
papille 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 papille had perforated 
each surface. 
C. Alderi. Pi. XV. fig. 9. 
Sponge branched, irregularly and widely anastomosing, and 
strongly lobed ; the lobes for the most part irregularly rounded, 
frequently 4th of an inch wide, placed close together, and united 
by a much-constricted stem : terminal twigs very fine, frequeutly 
linear for a considerable length, and bifurcating somewhat irre- 
gularly : papille small, rather variable in size, the largest about 
goth 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 ;1,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 Pectwnculus pilosus on the coast of the 
Isle of Man : as yet it has occurred in no other locality. 
C. corallinoides. Pl. XV. figs. 1 & 2. 
Sponge freely and distinctly branched, slightly anastomosing, 
and regularly and strongly lobed ; the lobes about 4th of an inch 
Ann. & Mag. N. Hist. Ser. 2. Vol. iii. 22 
