Eevieios — Br. E. Kolcen. 281 



lias tersely stated, the power of repeating a classification does not 

 always imply any real knowledge of a group in a student. They 

 are useful summaries to work by, and we expect from Prof. Hall and 

 his indefatigable assistant. Prof. J. M. Clarke, some definite state- 

 ment on this vexed point in conclusion. At present they stand alone 

 in the rejection of family groupings of genera in name, although 

 they seem tacitly to admit the necessity of some such grouping by 

 writing persistently of "orthoids," "productoids," " terebratuloids," 

 etc. This is all very well in its way, but it imposes on the student 

 the burden of defining whether "orthoid," and other generic and 

 subgeneric mutations, which have been described collectively by 

 other authorities as the "Orthid^," " Productidse," etc., is intended to 

 be understood, or whether the term " orthoids " is meant to define 

 merely the eight species to which that genus is by Hall restricted. 



These remarks are not offered in any carping critical spirit. It 

 would be absurd to deny the right of the State Palaeontologist of 

 New York to formulate a new classification ; no one can have 

 a better claim in Europe or America. We note the point as a 

 diflSculty in generalization and likely to puzzle the students to 

 whom this handbook of the Brachiopoda is addressed, and one, 

 therefore, that should be removed in the concluding portion of 

 this most praiseworthy manual. We have noticed the work at some 

 length, because one would scarcely expect to find a handbook for 

 students enclosed within the covers of an annual Museum Keport. 

 Science just now must be in "a parlous state," indeed, in America, 

 when scientific men of acknowledged repute and standing are driven 

 to adopt such a roundabout method of publication. It is to be 

 presumed that Hall's Handbook to the Brachiopoda will be pub- 

 lished separately on its completion. Agnes Cbane. 



IV. — The Past World and its Evolution. (Die Vorwelt und ihre 

 Entwicklungsgeschichte.) By Dr. Ernst Koken. Koyal 8vo. 

 pp. 654, 117 Figures in the text, and two Maps (Plates I. 



and II.). (Leipsic : Weigel, 1892.) 



IN the preface the author wishes us to understand that he addresses 

 himself not to specialists, but to a wider circle of readers ; 

 we venture, however, to predict that, like Neumayr's Erdgeschichte, 

 the present book will, before long, be found as well in the libraries 

 of geologists and palaeontologists as in those of the Gebildete Kreise 

 generally. 



The three first chapters (The Interior of the Earth and the Hardened 

 Crust; The Formation of Mountains ; The Notion of Time in Geology) 

 are a sort of introduction, and are almost exclusively geological in 

 their contents, as is chapter xii. (Quaternary and Ice Period). 

 Chapters iv.-xi. are dedicated to the different " systems," beginning 

 with the Cambrian and ending with the Tertiary ; in these the 

 palseontological part predominates. Chapter xiii. is dedicated to 

 the Animal World in Quaternary times. 



The author is not only conversant with the very latest work done 

 in every department of the wide field covered by his subject — in this 



