with descriptions of new Species. 343 
rous, small, imperfectly lozenge-shaped lobes, about ;4,th of an 
inch wide, crowded on each other and united each to its neigh- 
bours by small cylindrical stems, four or five passing from each 
lobe : terminal twigs short and linear: papille large in compa- 
rison with the lobes, measuring nearly ;,th of an inch in dia- 
meter, rather numerous, and disposed on the surface of the ma- 
trix without order. Spicula of two forms, one much larger than 
the other, being upwards of ,1,th of an inch long, straight, stout, 
and generally tapering to a fine point at one end; the other ter- 
mination is furnished with a globular head, a little inclined to 
oval. The other form of spiculum is not more than half as long 
as those with heads, but is only a little inferior in thickness : it 
is fusiform, tapering gradually to a sharp point at each end, and 
is abruptly bent in the centre. 
This species occurs in Tridacna gigas ; the lobes appear to be 
arranged in a somewhat branched manner, but on account of 
their close approximation the order is obliterated, Some of the 
uniting stems are larger than the rest, and most probably indi- 
cate the main branches. 
C. purpurea. Pi. XII. fig. 6. 
Sponge made up of numerous, close-set, somewhat elongated 
and angulated lobes or nodules about ;4,th of an inch in length, 
united by several delicate, cylindrical stems ; and when dry of an 
obscure purple colour: terminal twigs short, linear: papille 
small, not very numerous, passing through the matrix without 
apparent order. Spicula numerous, of two sorts; one is larger than 
the other, ;4,th of an inch in length, linear, slightly and re- 
gularly bent, with the ends a little enlarged and rounded. The 
other kind of spiculum is about half as long as the preceding, 
and resembling it in form, with the exception that the extre- 
mities are not enlarged ; it is likewise irregularly spinous through- 
out its entire length. 
This species is readily distinguished by its purple colour and 
by the peculiar characters of its spicula. In general form there 
is considerable resemblance between it and C. nodosa ; the lobes, 
however, are much smaller than they are in that species, and the 
stems that unite them are less numerous ; they are likewise elon- 
gated. The C. purpurea oceurs in Tridacna gigas. 
C. angulata. Pi. XV. fig. 13. 
Sponge formed of a few irregularly shaped and angulated lobes 
or nodules, sometimes measuring 4th of an inch wide, placed 
close together, and united by a few small, short, cylindrical or 
flattened stems: terminal twigs rather short, simple, small and 
linear : papille not very numerous, irregular in size and arrange- 
