54 NATURAL SCIENCE [July 



the supply of which has always been abundant. But a growing need 

 was felt for a general and elementary ' Zoology ' written more par- 

 ticularly so as to express the views of the majority of teachers in this 

 country. The differences between the teaching and current doctrines 

 in one country and those in another are not great, and perhaps not 

 very important, yet they are distinctly appreciable. Mr Sedgwick 

 has now brought out the text-book of general and systematic zoology 

 of which the first volume is before us. In his preface the author 

 tells us that it was his original intention to issue a revised edition of 

 Claus' well-known ' Lehrbuch ' ; but that he changed his plan, and 

 has written a book which is a new work although following the same 

 lines as the older one. 



The present text-book is intended to help the student who has 

 already acquired a preliminary knowledge of certain types of animal 

 life, and wishes to proceed to a more thorough study of zoology. 

 The whole work will probably be completed in two volumes. The first, 

 with which w T e are now concerned, deals with the Phyla Protozoa, 

 Porifera, Coelentera, Platyhelminthes, Nemertea, Nematelniinthes, 

 Piotifera, Mollusca, Annelida, Sipunculoidea, Priapuloidea, Phoronidea, 

 Polyzoa, Brachiopoda, and Chaetognatha. The second volume will 

 include the Arthropoda, Echinoderma, and Vertebrata, with general 

 discussions of " the facts and principles of Zoology." 



The work is distinguished by the clear and straightforward manner 

 in which it is written ; whether we agree with the author or not, we 

 never have any doubt as to his meaning. Superfluities are rigidly 

 excluded, and by the judicious use of small type the bulk of the 

 volume is kept within reasonable bounds. Throughout, the facts are 

 treated in strictly systematic order, as many families are mentioned 

 as possible, and a large number of genera are named. The book will, 

 therefore, prove a very useful work of reference, in which both facts 

 and names can be readily found — a task rendered easy by the help of 

 an excellent index at the end of the volume. 



As we should expect from the pen of an author whose researches 

 have extended over such a wide field, and whose experience in teach- 

 ing is so great, this volume is well up to date, and singularly free from 

 those blunders which so frequently disfigure text-books. This is no 

 doubt partly due to the fact that Mr Sedgwick has often secured the 

 help of specialists in reading over and correcting the proofs. 



Mr Sedgwick, as is well known, is an opponent of the ' cell-theory ' 

 — accordingly in his general definitions he endeavours to avoid the 

 use of its ' language.' For him, the Metazoa are merely multinuclear 

 animals, " in which the nuclei are for the most part arranged regularly 

 and with a definite relation to the functional tissues." We must con- 

 fess that this attempt to boycott the ' cell-theory,' which after all is 

 merely a descriptive statement of perfectly obvious facts, tends to 

 become somewhat pedantic, and moreover is futile, since again and 

 again the writer is obliged to return to " the language of the cell- 

 theory," without which no description of Metazoan tissues can be 

 intelligible or correct. If certain authors have erroneously taught 

 that the cells of a tissue or embryo are entirely independent organisms, 

 surely this is no reason why we should abandon the use of the term 

 cell, any more than we should give up the words ' segment ' or ' meta- 



