Address of the President. 
31 
cellular arrangement is more or less obvious in the section, 
but in which no distinctly-cellular residuum is left after decal- 
cification, I should infer that the processes of vacuolation and 
of consolidation had commenced, but had not proceeded far, 
when the calcification took place. Lastly, in those in which 
(as in Pinna) a very definite residuum, apparently cellular, is 
left after decalcification, the very striking resemblance which 
this bears to that stage in the vacuolation and consolidation of 
a layer of protoplasm about to form a leaf (as described and 
figured by Mr. Wenham) which immediately precedes the 
formation of distinct cells, induces me to think that such must 
have been the stage in which the sarcode-layer must have 
undergone calcification. Hence, whilst agreeing with Mr. 
Huxley that in few (or perhaps none) of the structures which 
I have described as cellular, are any complete cells ordi- 
narily formed, I still believe that in all of them there has been 
a nisus more or less operative, towards the development of 
cells ; their differences lying solely in the greater or less 
degree of differentiation, tending towards the production of 
perfected cells, which had manifested itself in the sarcode at 
the time of its calcification. 
I am strongly disposed to believe, that the same doctrine 
will apply to many other animal structures, in which the pre- 
sence of a cellular organization is affirmed by some and denied 
by others. If, for example, you look at the scale of an Eel., 
you observe that its otherwise homogeneous substance is marked 
out by ovoidal spaces, which suggest the idea of cartilage-cells 
with an intervening matrix. By Professor Williamson, who 
has carefully studied the structure of fish-scales, a layer of this 
kind has been shown to be of very general occurrence ; and 
he considers these ovoidal spaces to be " botryoidal concre- 
tions " of calcareous matter, having no relation whatever to 
cells. And he puts the like interpretation on analogous 
appearances exhibited by various egg-shells, which have been 
regarded by Professor Quekett and others as indicative of a 
cellular organization. Now the microscopic appearance of 
the scale of the Eel so precisely resembles that of the leaf- 
forming layer of protoplasm, as figured by Mr. Wenham, that 
I can scarcely doubt that its ovoidal spaces are vacuoles 
formed with a view (as it were) of becoming cells ; and that 
the regularity of the shape and disposition of the calcareous 
concretions is determined by that of the vacuolations. And 
the condition of such egg-shells as exhibit an appearance of 
cellular structure, so closely resembles tljat of many shells of 
mollusks, in which there is a cellular areolation without well- 
