304 JULIAN S. HUXLEY 
with the high power was the association of the small types of 
amoeboeytes I propose to call finger-cells with the 
dermal cells in the blown-out region. This was observed both 
at Wood’s Hole and at Plymouth. In surface view the dermal 
epithelium is seen to consist of a number of granular areas 
(fig. 12)—cell-bodies—separated by transparent areas, where 
the protoplasm is extremely thin. Cell-junctions cannot be 
seen in vivo. Below each granular area is seen an irregular 
stellate figure. On careful examination this is seen to consist 
of a number of finger-cells radiating from below the centre 
of the cell-body. Optical section of the periphery gives a profile 
view, when the body of the dermal cell is seen to be sharply 
marked off from the underlying finger-cells. Similar finger- 
cells are seen to protrude, but singly, from the inner mass of 
choanocytes. The meaning of this arrangement of finger-cells 
remains obscure. 
The cultures containing the large dermal blow-outs above 
referred to were examined again later. Almost all had produced 
some spicules, and a considerable proportion had metamor- 
phosed into functional young sponges of the * Olynthus’ stage. 
In my previous work (Huxley, 7, p. 169) I never obtained 
fixed Olynthus stages from restitution masses. Here, however, 
some 25 per cent. of them were firmly attached. A few of 
these were of great regularity of form (fig. 7, a), again surpassing 
any obtained previously. Others, however, showed marked 
irregularities, more pronounced than any seen in 1910, often 
appearing as if preparing to form a second osculum. In no 
case, however, was a second osculum seen, or even a rudimentary 
second oscular crown of spicules. The most remarkable 
thing about these forms was the large size shown by many 
of them, far exceeding that of a newly-metamorphosed larva. 
Thus, although large size is associated with less viability of 
restitution masses, yet even very large masses, provided they 
remain healthy, can metamorphose into normal-type Olynthi 
if the various sorts of cells are present in correct proportions. 
Some idea of the normal size of Olynthi from larvae can 
be got by comparing the figures of larvae (figs. 9,a; 10, a, 
