with descriptions of new Species. 343 



rous, small, imperfectly lozenge-shaped lobes, about jT-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 : papillae large in compa- 

 rison with the lobes, measuring nearly 23-^^ °^ ^^ 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 ^7*^ ^^ ^^ ^^^ lo^^gj 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 spiculuni 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. PL XII. fig. 6. 



Sponge made up of numerous, close-set, somewhat elongated 

 and angulated lobes or nodules about y\jth of an inch in length, 

 united by several delicate, cylindrical stems ; and when dry of an 

 obscure purple colour : terminal twigs short, linear : papillae 

 small, not very numerous, passing through the matrix without 

 apparent order. Spicula numerous, of two sorts; one is larger than 

 the other, y^o^^ ^^ ^^ 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 occurs in Tridacna gigas. 



C. angulata. PI. XV. fig. 13. 



Sponge formed of a few irregularly shaped and angulated lobes 

 or nodules, sometimes measuring ^th 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 : papillae not very numerous, irregular in size and arrange- 



