Can we doubt (remembering that many more individuals are born than can possibly survive) that individuals having any advantage, however slight, would have the best chance of surviving and of procreating their kind.On the other hand, we may feel sure that any variation in the least degree injurious would be rigidly destroyed. This preservation of favourable individual differences and variations,...

Two new species of the genus Pseudolathra Casey from mainland China are described and attributed to their respective species groups, P. cylindrata sp. n. from Hubei and Sichuan, and P. superficiaria sp. n. from Yunnan. Pseudolathra pulchella (Kraatz, 1859), P. transversiceps Assing, 2013 and P. bipectinata Assing, 2013 from Yunnan are reported from China for the first time. The history of the e...

The fossil record of the Cambrian Period has been known as a problem for evolutionary thegfory since Darwin’s Origin of Species in 1859. Darwin was aware of the sudden appearance of complex animal forms in the Cambrian from his own collecting in northeastern Wales. Complex animal forms such as trilobites seemed to appear with geological suddenness with no apparent ancestors in older rocks below...