intentional adhesion to a predetermined plan throughout a whole group is totally negatived by the occurrence of occasional deviations from the pattern." Let this assertion be examined first in the light of facts, and secondly by the absence of facts. The hypothesis is that some primitive race of articulated animals, possessed by some means of the twenty segments, transmitted this ancestral trait to hundreds of thousands of species having no community of structure in other respects. Unfortunately for the theory, no figures can measure the chances against the preservation of a single pattern through such a multitude of differing organisms descending from a common stock. Infinity alone can express the chances against such a result. While, according to the theory, the deviations from the original type were constantly working out new organisms of the most diversified forms, until there came to be hundreds of thousands of new species differing from each other in all but this one peculiarity--a diversity which is supposed to have been caused by the fundamental law of evolution--how did it happen that the same law did not break this uniformity of articulation? If it was potent enough to differentiate the enormous multitude of these animals in all other traits, why did it not vary the number of segments with which the primitive race was endowed? Is the law of evolution limited or unlimited? If it is limited in its effects, then there are patterns of animal structure which it has not modified, and the presence of which in hundreds of thousands of different species must be explained as a form of structure designed for some end that was to be common to a great multitude of different beings. If the law of evolution was unlimited in its power, then the community of pattern has had to undergo chances of destruction or discontinuance that are immeasurable; as there can be no measure which will represent to the mind the infinitely diversified and innumerable causes that have produced the dissimilarities which compel a classification into the different species, upon the hypothesis of their descent from a common stock. Grant, too, for the purpose of the argument, that the occasional deviations from the pattern of twenty segments, producing a few groups with a smaller number of articulations, are reconcilable with the belief that some later ancestral form became endowed with the smaller number which it transmitted to its descendants. How came that later ancestral form to be endowed with the smaller number of segments? Was there a still more remote ancestral race, which in some way became possessed of the smaller number, or did the spiders and the mites, in the countless generations of evolution, branch off from ancestral races having the full number of twenty segments? Upon either supposition, what an infinity of chances there were, against the natural selection of the smaller number, and against its preservation as the unvarying type of