REVIEWS 711 



mammals (Monotremata) ; and on the same page the author follows Dr. Gidley in 

 associating the extinct Multituberculata with the Marsupialia, thereby ignoring the 

 views of Dr. Broom, who considers that their relationships are clearly with the 

 Monotremata. Then, again, it is distinctly startling to be informed (p. 399) 

 that no fossil dolphins are known ; while the statement that the mammal-like 

 anomodont reptiles of the Permo-Trias are mainly restricted to New Mexico and 

 South Africa (p. 356) is decidedly misleading, in view of their abundance in Russia. 

 As a minor matter, the statement (p. 345) that there is only one species of the 

 African ganoid fishes of the genus Polypterus is scarcely accurate. It may be 

 added that in recognising only nine orders of reptiles the author differs widely 

 from the views of his compatriot, Prof. Williston, who, in his recently published 

 Water Reptiles, admits no fewer than fifteen. None of these, however, is anything 

 more than one of those slips which are, unhappily, bound to occur in works of 

 this comprehensive nature ; and it may be confidently affirmed that Prof. Shimer's 

 volume is in every way entitled to a place among the best class of elementary 

 biological text-books, more especially as the mode of treatment of the subject 

 serves to emphasise the too often forgotten fact that palaeontology is nothing more 

 than the botany and zoology of past epochs, and not a science by itself. 



R. L. 



ZOOLOGY 



Textbook of Embryology. Edited by Walter Heape, M.A., F.R.S. Vol. i. 

 Invertebrata. By E. W. MacBride, M.A., D.Sc, LL.D., F.R.S- 

 [Pp. xxxii + 692, with 468 Illustrations.] (London : Macmillan & Co., Ltd. 

 Price 25^. net.) 

 It is a difficult task for one man to compress within the limits of a single volume 

 a subject of so wide a scope as the embryology of the invertebrates, more especially 

 when this includes not only the Invertebrata but also the Protochoidata, those 

 borderline forms usually included with the Vertebrata in the term Chordata. 

 Prof. MacBride has accomplished this task successfully, and produced a book 

 that will be welcomed for its utility. The subject matter of such a work might 

 have been presented in one of two ways— either in an encyclopaedic manner, in 

 which as many statements as possible are collected under the one heading, or 

 under the type system, in which the general principles are propounded and 

 illustrated by reference to one or a few types. The author has, and we think 

 wisely, adopted the latter plan, and has been guided in the choice of his types by 

 those that have been fairly satisfactorily or recently worked out and that may be 

 obtained in temperate latitudes. This treatment appeals particularly to the 

 student, and one who works through this book will get a thorough and sound 

 knowledge of his subject. 



Perhaps because it is hardly possible for one person to be equally versed in 

 all the invertebrate groups, we find that their treatment varies somewhat, and the 

 best chapters are those at the end dealing with the Echinodermata and Proto- 

 chordata, in which Prof. MacBride's own researches are already widely known. 



While in entire agreement with the author's desire to keep the literature lists 

 as short and up-to-date as possible, it would appear that brevity in some cases 

 has been secured at the cost of excluding good recent work. In the pages dealing 

 with the Hydrozoa no reference has been made to Kiihn's papers on budding 

 (1909) and the formation of gonophores (1910), which are more recent than those 

 of Gotte, nor to his last paper on the development of the Hydrozoa (191 3), which 

 is of great value because of the very full bibliography it contains. The chapter 



