164 KANSAS CITY REVIEW OF SCIENCE. 
both are of the same mathematical rank. Nor ls there, among our earlist fossils, 
the slightest trace that one has been derived from the other, or both from a com- 
mon parentage. Both appear in the Trenton epoch with the same distinctive 
characteristics which they possess in any later period. 
It is a principle of evolution, that the influence of climate, food and other 
circumstances are largely, and, in the lower forms of organism, the entire cause 
of the variance of structure. In these low, radiate forms ‘‘natural selection ” 
can have no influence. With this principle before us, we would draw attention 
to the extremely monotonous surroundings in which the Radiates, particularly 
the Corals, have always existed. This can be clearly seen in the living species 
and genera. ‘They are nearly all confined within the twentieth degrees of latitude 
on both sides of the Equator. They are most abundant in the Pacific ocean. 
That body of water, even more than the other tropical oceans, is noted for its 
uniform temperature and the uniform proportion of saline elements held in 
solution. Many of the Pacific islands have a maximum range of less than 
15° Fahrenheit of extreme temperature in the year, and the adjoining waters 
have far less, at the depth of which most of the corals live. The zone of coral 
life is limited to one hundred feet in depth, and most genera are confined to a 
belt of twenty vertical feet. The variation of temperature in the year for the 
lower portion of this zone, is probable not over five degrees. ‘This portion of 
the ocean, in which the corals live, is more uniform in its clearness and saltness 
than in its temporature, as when these vary the animals die. The food which 
most if not all of them eat is the same. Their chemical, coral, calcite structures 
are identical. 
Now with all these extremely monotonous conditions of the coral Polyps and 
other Radiates, why do we find so great a variety of species, genera and even 
orders flourishing on the same reef? If diversified conditions, according to Prof. 
Darwin and his associates, give new forms, why should circumstances, such as 
we have described, present us with such varied ones? Or if they owe their 
origin to diversified conditions which are lost to our knowledge by the ‘‘imper- 
fection of the geological records,” why should not our monotonous and very 
uniform conditions of the age of man have reduced these numerous genera and 
species to a few forms? 
Geologists and paleontologists have clearly settled the question that in all ages 
of the globe, wherever corals have existed, the conditions of the ocean, in all 
respects, have been the same as that in which they now exist. In collecting our 
fossil Radiates from the oldest strata, though in certain localities some species 
may predominate, we always find associated others of very different generic 
affinities. Yet they must, like those of the present tropics, have lived in the 
same water under the same climatic conditions. 
Barrande classifies over thirteen hundred species of Radiates of the utmost 
extremes of genera from Star-fishes and Crinoids to Polyps, all gathered from 
