solution of extremely important problems of animal morphology, particularly those of segmentation, budding, and strobilation.
Professor Semper did not succeed in obtaining general acceptation of his views on the derivation of vertebrates, but the observations and arguments on the special point, and on general questions, too, set forth in the works relating to them, exercised a remarkably stimulating influence on the further discussion of the problems involved.
The second work in which Professor Semper considered the zoölogical problems raised by Darwin's theory is the book on Animal Life as affected by the Natural Conditions of Existence. The fundamental thought of this book, as defined by the author in his preface, was that, as Jaeger had said, enough had been done in the way of philosophizing by Darwinists, and the task now presented was to apply the test of exact investigation to the hypotheses that had been laid down. Without pretending to have made a complete presentation, his end would be attained if he should have given an impulse to research, on however small a scale, so long as it should be systematically conducted and thoroughly carried out—"if only it should contribute to extend my own conviction as to the uselessness of casual and disconnected observations." The book is described by Dr. Schuberg as a remarkably stimulating one, and no compilation; for, besides permeating and enriching the subject with numerous new thoughts, he incorporated in it a very large number of his own observations, made for the most part during his voyages. Professor Semper further contributed to the literature of zoölogy numerous smaller and special papers, a considerable proportion of which, his own, or composed with the co-operation of his pupils, were published in the Arbeiten aus dem Zoölogisch Institut in Würzburg.The whole list of his writings, as given by Dr. Schuberg in the biography published in that journal, comprises ninety titles.
Professor Semper contributed also to other fields of literature. His journeys in the Philippine Islands took him into regions rarely visited by Europeans, and of the anthropology and ethnology of which little was known. He included these features within the range of his studies, and was able to cast considerable light upon them. Besides single essays, two works are especially worthy of notice as fruits of his industry in these lines of research—The Philippine Islands and their Inhabitants, which treats of the geographical and ethnological aspects of the group; and The Pelew Islands of the Pacific Ocean, presenting a corresponding view of that still less known region. In 1869 he became one of the editors of the Archiv für Anthropologic. Considerable literary value also attaches to his academical lectures.