On Specimens of Eozoon Canadense. 203 
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“acervuline”” mass. The chambers, which, on the sup- 
position above stated, were originally filled with the sarcodic 
matter of the animal, were after death and the burial of 
the skeleton in some calcareous sediment, occupied with 
mineral substances introduced by infiltration, and more 
especially with serpentine and pyroxene, which were at the 
same time being deposited in layers and concretions in the 
surrounding material. When well preserved, the calcareous 
lamin are seen to be traversed with innumerable canals, 
terminating in very fine tubuli. These canals are occupied 
by serpentine, pyroxene or dolomite, or by limestone, 
according to the state of preservation. (See Figs. 2, 3, 4). 
The masses of Hozoon sometimes consist of as many as 
one hundred and fifty laminz superimposed. Originally flat 
or rounded, they assumed in growth club-shaped or turbinate 
forms, and sometimes by coalescence formed wide sheets or 
irregular masses, in which case they are often observed to 
be traversed in their thickness by conical or cylindrical 
tnbes oroscula. The outer surface and the walls of these 
tubes were strengthened by bending and coalescence of 
the lamine. The mode of growth would be similar to 
that of more modern organisms of the genera Loftusia, 
Carpenteria and Polytrema, and to that of some kinds 
of Stromatopore. Finally, these calcaceous tests were liable 
to be broken up and scattered in fragments over the 
sea bottom, constituting the material of beds of organic 
limestone, like the coral sand that surrounds modern reefs 
and islands. 
Assuming Hozoon to be a fossil animal of the char- 
acters above described, its mode of preservation in the 
ordinary serpentinous specimens is more simple than 
that of many fossils of later date. The calcareous walls 
have remained substantially unchanged, except that they 
have become somewhat crystalline in structure, and in 
many cases have assumed the crystalline cleavage of cal- 
cite; but this change is quite common in Paleozoic 
shells and crinoids, The chambers have been filled and the 
canals and tubuli traversing the calcareous test have been 
