106 Mr. H. J. Carter’s Contributions to our 
nules”’ are just as brown and large in Chondrilla sacciformis, 
but in this, as well as in C. nucula (where they are smaller), 
have no definite arrangement, beg grouped together irregu- 
larly in small parcels of four to twelve granules, each without 
any appearance of ced-wall whatever (fig. 9). Similarly com- 
posed are the pigment-cells of the Ceratina, to which I have 
alluded as “‘ so-called,” because in no instance have I been 
able to demonstrate a cell-wall by chemical reagents, any more 
than in Ameba; hence all that can be stated in this respect 
is that the nucleus and granules appear to be suspended in a 
sarcodic substance which, in some of the Ceratina, and in 
Stelletta aspera &c., has a definite elliptical or globular form 
like that of a “cell ;” while the “parcels” of granules in the 
two Chondrille just mentioned have no defined form at all, 
and but for their being thus congregated might be generally 
distributed throughout the filamentous trama (fig. 6), of which 
the substance of these sponges is chiefly composed, for the 
colouring effect which they produce. 
Again, if we return to the pigmental or coloured cells of 
Aplysina carnosa &e. and Spongia officinalis, they will be found 
to possess the irregularly stellate form mentioned, in which 
the ray-like processes are prolonged into pseudopodial appen- 
dages that unite with each other. ‘This is particularly well 
seen in fresh specimens and those which have been preserved 
in spirit of Dysidea (Spongelia) fragilis (fig. 4), where, 
although colourless, or nearly so, on the surface as well as in 
the interior, these cells are the centres of a network of pseudo- 
podial reticulation which spreads throughout the sponge, and 
is so soft and delicate that, on drying, the whole structure is 
irretrievably lost in the gum-like consistence which it then 
assumes. 
Thus the well-defined pigmental cell with its deeply 
coloured purple granules, as well as the stellate form with its 
lighter ones, may be fairly assumed to have been produced by 
evolution from a pseudomorphous wncoloured condition ; while, 
on the other hand, the dermal cell, when more elongated, might 
lead not only to the elliptical form (fig. 5), but to the fusiform 
filamentous element (fig. 6), of which the general structure of 
Ohondrilla &c. is chiefly composed, whereby, still possessing 
its contractile or polymorphic power, the whole mass might, 
in combination, be subjected generally or partially to this 
motive influence; for change of form cannot be effected with- 
out motion. 
Here it should be remembered that all the soft parts of a 
sponge are polymorphic, and that, as they are all evolved from 
a single cell at the commencement, they are only parts of the 
