NOTES AND MEMORANDA. 
211 
a kind of organic crystallization, the expression of some as yet 
unknown law of animal organization here acting untrammelled by 
adaptive modifications or by those needs which seem to be so readily 
responded to by the wonderful plasticity of the animal world.” 
The multicellular nature of Eadiolarians, it is pointed out, now 
depends entirely on the normal nature of their yellow cells, and on the 
correctness of the observations as to the centripetal cell-groups of 
Phjsematium. Neither of these phenomena can be reposed on as 
being certainly of the nature of true cells forming part of the normal 
organization of the Eadiolarians in which they have been found ; but 
even if they are so, and if we are compelled therefore to regard 
Eadiolarians as multicellular, their multicellularity is of a radically 
different kind from that of any of the Metazoa, and none of their 
parts, whether truly cells or not, have any valid claim to the denomi- 
nation of a tissue. 
In regard to the relations of the Eadiolaria to the other Protozoa, 
it is at present a disputed question whether it is the more natural 
arrangement to make on the one hand the Heliozoa, Eadiolaria, and 
Thalamophora three distinct and coequal equivalent groups, or on 
the other hand to form two great groups, the one containing, as two 
subdivisions, the Heliozoa and Eadiolaria, and the other the marine 
and fresh -water Thalamophora. On the whole, notwithstanding 
undeniable similarities in external form, chemical composition, and 
otherwise, the author is inclined to keep the Eadiolaria and Heliozoa 
provisionally apart as two equivalent and divergent groups, though 
unquestionably of all the above Protozoa the Heliozoa come nearest to 
the Eadiolaria. The distinctions which seem to justify this are : — 
Radiolakia. 
(1) A porous capsular membrane 
present. 
(2) A gelatinous investment present. 
(3) Reproduction by numerous zoo- 
spores, each with a nucleus and 
flagellum, but with no vacuoles. 
(4) Yellow cells present in almost all. 
(5) Entirely marine. 
( 6 ) 
Heliozoa. 
Absent. 
The much fewer separated reproduc- 
tive parts have each two flagella, 
several contractile vacuoles, and a 
nucleus with vacuoles and nucleoli. 
Absent. 
Almost entirely fresh water. 
Pseudopodia often with axis-fibre. 
The author observes, however, that (5) is much weakened by the 
discovery of the salt-water Heliozoa ; that with regard to (3), though 
the differences which exist between the reproductive processes are very 
great, yet greater differences exist between different Heliozoa, while 
the reproductive processes of so few Eadiolarians have been examined 
that it would be rash to feel confident that no important divergences 
will be hereafter found amongst them in this respect, and that as to 
the capsule the distinction would be weakened if it should turn out 
that young Eadiolarians, which have not yet acquired a capsule, never- 
theless show a differentiation of their sarcode into an inner and an outer 
layer, like the medullary and cortical parts of Heliozoa, and the 
distinction would be broken down if it should be shown that certain 
adult Eadiolarians have no capsule at all. 
