of the Fibre in the Spongida. 113 
nothing else, all the soft parts having been abstracted, leaving 
only a resilient mass composed of what will henceforth be 
ealled “fibre,” while the horny material of which the fibre is 
chiefly composed will be termed “ kerasine ”’ («épas), “‘ resem- 
bling horn, horny, corneous.”’ 
Yo all who are acquainted with this fibre, it must appear 
no less true than inexplicable how it can be so formed as in 
most cases to become axiated or cored with foreign bodies, or 
by spicules formed by the sponge itself. 
Tracing, then, the development of the fibre through the 
different orders of my proposed classification of the Spongida 
(““ Notes” &e. loc. cit.), we find that there is none in the 
Carnosa (ex. gr. Halisarca) ; that it makes its appearance 
in the Ceratina (Luffaria), where it is composed of horny 
Jaminee axiated by a granular core ; that foreign bodies appear 
within this core in the Psammonemata (Hircinia), and in the 
Rhaphidonemata (ex. gr. Chalina) spicules formed by the 
sponge itself, which are equivalent to the “ foreign bodies”’ 
in this respect; and so on throughout the other orders, where 
the spicules are held together by more or less kerasine. 
With reference to the presence within the fibre of foreign 
bodies or spicules developed in the sponge itself,it might at 
once be assumed that this must have preceded the formation 
of the laming: of horny material which enclose them, and that 
these bodies must have been placed there by that develop- 
mental intelligent power whose existence in every organized 
product is only known to us by its manifestations. 
Our object, however, is not to endeavour to find out what 
this power is, which may be said to be able to do any thing 
with every thing and every thing with any thing so far as we 
can see, but to observe the nature of the material and the 
sequence of its adaptation in the formation of the fibre. 
With this view it is first necessary to briefly define 
the elementary composition of the material of which the 
fibrous sponges are composed; and this may be divided into 
the soft and hard parts—the “soft parts” consisting of 
a transparent granuliferous substance (polymorphic when 
alive), in which are suspended nucleated granuliferous cells 
more or less alike but of different functions, the ampul- 
laceous sacs, the sperm-sacs, and the ova when developed, 
all together usually called the “ sareode” or ‘“ parenchyma ”’ 
(“ syncytium,” Hickel*). But of these, the part of most conse- 
* How far the whole of this may not be composed of a congeries of 
polymorphic cells or bodies, and the transparent granuliferous substance - 
itself (‘ Annals,’ 1849, vol. iv. p. 91, pl. xiv. fig. 2,dd) a united mass of 
them, in which their individualization can be no more distinguished than 
