112 Mr. H. J. Carter on the Development 
do not appear to be uncommon, although the unique histo- 
logical structure to which I have alluded has not, to my 
knowledge, been heretofore pointed out by any one but 
myself. 
I found one small, rugged specimen without label among the 
late Dr. Bowerbank’s collection of sponges; but it appears to 
have come from the south-west coast of Australia or the Indian 
Ocean; and although only a fragment (consisting of the 
remains of two thin fronds united at their base) altogether 
measuring about 5x 3 inches, the fibre and dry black-purple 
sarcode filling up the interstices of the thin lattice-like struc- 
ture are quite sufficient for identification, while the former, 
from its large size, here 1-12th inch in diameter at the base 
of the specimen, seems to ally it to J. Homed, Gray ; yet, as 
Dr. Gray states (/.c.) that the latter ‘‘chiefly differs from 
I. basta in the network appearing to be thicker and stronger,’ 
and “is only a young and partly-developed specimen,” while 
I. basta has received its designation also from the coarseness 
of its fibre, being like “ bast,” it may be that future obser- 
vation will identify the two, which thus differ from the more 
finely-fibred latticed one, viz. L. jlabelliformis. ‘The fibre, 
however, of Dr. Bowerbank’s specimen not only appears to 
be coarser but more oblique in the interstices of its reticulation 
than that of 1. flabelliformis, which, on the other hand, is 
more quadrate. As its histological character will be more 
particularly mentioned in the “ Development of the Fibre in 
the Spongida ” generally, which I propose to consider in the 
next article, there is no occasion for entering into it more 
at length here. 
The generic description given by Dr. Gray (loc. cit. p. 50) 
may, however, be rendered more complete by adding to 
it the following histological characters, viz. :—‘* Sarcode 
charged with dark purple pigmental cells, especially numerous 
on the surface and in the horny lamine of the fibre, which 
appear to be secreted by them (fig. 12). Core of the fibre 
granular, grey. or colourless, often enclosing foreign bodies, 
but no pigmental cells.” 
XIII.—On the Development of the Fibre in the Spongida. 
By H. J. Carrer, F.R.S8. &e. 
[Plate IX. ] 
For a familiar example of the fibrous structure in the Spongida 
the sponge, of commerce may be instanced, as consisting of 
