276 NATURAL SCIENCE [April 



shown not to be Holothurians, real advances were made, not only in 

 classification, but also in the knowledge of the morphology of those 

 animals. The attempt to establish an obviously polyphyletic group 

 like the Vermidea, containing such forms as Sternaspis and Lingula, 

 Eotifers and Phoronis, Echiurus and CejjJialodiscus, can only, we 

 think, retard the progress of zoology, and confuse the points at 

 issue. To the authors' exclamation that " Ics Molluscoides ont vecu,' 

 it can only be answered that we hope the Vermidea, as a group, 

 will never live. 



Throughout the volume the numerous figures in the text are both 

 new to text-books, and good ; many of them are much improved by 

 the use of colours. Quite a new feature, of course, is the introduction 

 of plates with highly-finished coloured figures. Always instructive, 

 and generally original, these plates are often excellent in conception 

 and execution. We may note especially those dealing with the 

 Bryozoa and Eotifera. 



In this work Messrs Delage and Herouard have successfully kept 

 up the high standard of excellence set in their first volume on the 

 Protozoa, and this notwithstanding the many and great difficulties 

 they must have met. All teachers and advanced students of zoology 

 will be grateful for such a reliable guide to the study of rather 

 obscure groups of animals, generally somewhat neglected in text- 

 books, and will look forward with eagerness to the appearance of the 

 next volume of the Zoologie Concrete. E. S. Goodkich. 



An American Text-Book of Geology 



An Introduction to Geology. By William B. Scott. 8vo, pjD. xxvii + 573, with 169 

 figs, and 12 .special plates of fossils. New York : The Macmillan Co., 1897. 

 Price 8s. 



From the first glance there is a refreshing air ol' newness about this 

 beautifully printed volume, giving a good impression which improves 

 on further acquaintance with the work. It is copiously illustrated, 

 not only with the usual diagrams, but also with exquisite photographs 

 of scenery and special features of geological interest ; and it is further 

 embellished with twelve plates of typical American fossils, drawn by 

 Mr Eudolph Weber in his well-known effective style. It is essentially 

 an American book for American students ; but the chapters on 

 physical geology can, of course, be appropriately used for teaching 

 purposes in any country, while those devoted to historical geology, 

 though essentially from the American standpoint, are characterised 

 by a breadth of view which is unusual in a geological handbook of a 

 strictly elementary character. 



Dr Scott has for many years held the Professorship of Geology 

 and Palaeontology in the University of Princeton, New Jersey, and 

 the arrangement of his book is the outcome of considerable experience 

 as a teacher. After a few introductory remarks, there is a chapter on 

 the rock-forming minerals. Dynamical geology follows, the igneous 

 agencies being first treated, then the surface agencies, and the latter 

 classified under the headings of destructive and reconstructive pro- 

 cesses. Structural and physiographical geology form the subject of 

 the next two sections ; and historical geology occupies the final 200 

 pages of the book. 



