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European allies similarly — ‘‘ leaves less toothed, buds and seeds 
smaller, fewer branchlets, etc.” i 
In his sixth chapter on ‘ Species and Time” he maintains with 
- much reason that “ the mass of palæontological evidence is indeed 
overwhelmingly against minute and gradual modification,” and that 
there is “ no evidence of past existence of minutely intermediate 
forms when such might be expected œ priori.” “ All the most 
marked groups, bats, pterodactyls, chelonians, ichthyosauria, an- 
ura, etc., appear at once upon the scene. Even the horse, the ani- 
mal whose pedigree has been probably best preserved, affords no 
conclusive evidence of specific origin by infinitesimal, fortuitous 
variations; while some forms, as the labyrinthodonts and trilo- 
bites; which seemed to exhibit gradual change, are shown by fur- 
ther investigations to do nothing of the sort.” ‘‘ Now all these 
‘difficulties [of time, and the absence or rarity of fossils in the 
oldest rocks, etc., etc.,] are avoided if we admit that new forms 
of animal life of all degrees of complexity appear from time to 
time with comparative suddenness, being evolved according to laws, 
in part depending on surrounding conditions, in part internal — 
similar to the way in which erystals (and, perhaps from recent re- 
searches, the lowest forms of life) build themselves up according 
to the internal laws of their component substance, and in harmony 
and correspondence with ‘all environing influences and conditions.” 
The latter clause is unnecessarily vague, substitute embryological 
laws, or changes (for the differences between species, and espec- 
ially genera, arise in all probability for the most part during the 
growth of the embryo), and we would agree with the author’s 
meaning. 
This is as far as the treatise goes, the author’s aim being simply 
to show that ‘‘ species have been evolved by ordinary natural laws 
(for the most part unknown) controlled by the subordinate action 
of ‘Natural Selection, ” acting with the Divine concurrence. 
What are these natural laws? The author has evidently over- 
looked the writings of certain naturalists in this country, who have 
endeavored to show that Natural Selection is insufficient to ac- 
count for the origin of generic and specific forms. Professor E. 
D. Cope in his “Origin of Genera”* has attempted to show, and- 
we think with much success, that genera are produced by the ac- 
* Proceedings of the Academy of Natural Science, Philadelphia, 1868. 
