114 Anniversary Address to the 
elevated zoological position led to many an argument against 
support of the theory of the prevalence of a warm climate 
during the ante-tertiary epochs, from the fact of the abun- 
dance of chambered cephalopods in the ancient sea-beds of 
now cold or temperate latitudes. The abundance of minute 
chambered Cephalopoda in the North Atlantic at the present 
time, and their almost universal distribution, were confidently 
appealed to as conclusive against the inference. Their num- 
ber in the later formations, when the genera of Ammonitoida 
and Nautiloida had become scarce or disappeared for ever, 
was interpreted only as a continuance of the same class under 
new and minuter forms. Analogy was mistaken for affinity ; 
and substitution of one group for one totally and organically 
different although in the mere form of test not dissimilar, 
was mistaken for succession and representation within the 
sphere of one type. But the discovery of Dujardin led the way 
to an entirely new interpretation of the value of the Rhizopoda, 
and a new view of the part they play in time. Proving, from 
good evidence, to be among the lowest of animal forms, to 
be in fact Protozoa like Amoeba, but differing from both Pro- 
teus and the animal element of the sponge by their invest- 
ment with a hard and symmetrically arranged (generally in 
spiral symmetry) exo-skeleton, it is most interesting to note 
that their advent and maximum development have been, not 
during the apparent dawn of life, but amid the later epochs, 
and chiefly during those ages which many paleontologists 
regard as especially characterized by the highest forms. of 
the animal kingdom. Indeed, so far as we know at present, 
the whole great group of Protozoa—the group that stands 
as it were at the very base, and constitutes the rudiments of 
the animal series—is as characteristic of the tertiary sec- 
tion of time as the Vertebrata themselves are. A compar- 
able phenomenon is becoming rapidly manifest in the mol- 
luscan subkingdom, now vastly increased by the accession of 
the Polyzoa to its ranks. These curious, lowly-organized, 
zoophytoid mollusca, instead of being the first of their type 
to appear, were preceded by members of all the higher orders 
of it, and do not become of much chronological value until 
the testaceous forms of the highest class of Mollusks occur, 
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