238 



THE ZOOLOGIST. 



Mr. Shipley's contribution belongs to the older and sounder 

 method, one that will come to its own again, when original 

 guessing will not be considered philosophical speculation. At 

 the same time it is impossible to treat the Insecta in the confines 

 of a section ; the class, dealt with fully and universally, would 

 require a series of volumes. 



It is a great satisfaction that in this publishing era of " Nature 

 Books" such works as the one under notice should be obtainable 

 for reference by zoologists. It has been well said that every 

 book has many authors, and the authorities mentioned at the 

 foot of each principal section support that suggestion. At the 

 same time the reader will reflect that all would probably not 

 make a precisely identical list ; there might be a difference both 

 in inclusion and exclusion. 



A Treatise on Zoology. Edited by Sir Kay Lankester, K.C.B., 

 M.A., LL.D., &c. Part VII. Appendiculata. Third Fas- 

 cicle : Crustacea. By W. T. Calman, D.Sc. Adam & 

 Charles Black. 



The present volume is devoted to the Crustacea, is written 

 by a specialist thereon, and adequately describes this large and 

 important class of the Arthropoda from the morphological and 

 developmental purview. We trust that Dr. Caiman will in 

 another publication as fully describe the Crustacea from the 

 taxonomical, bionomical, and distributional standpoint. Even 

 a new but authoritative volume on the British Crustacea will 

 be appreciated. 



To those who accept definitions as helps rather than dogmas, 

 Dr. Caiman's caution in this respect will find adherents in 

 specialists on other classes of animal life. He writes of the 

 Crustacea: — " The Class presents so wide a range of structural 

 diversity that it is all but impossible to give, in a few words, a 

 definition which shall apply to all its members." , And after 

 detailing his criteria he is compelled to add: — "But while these 

 characters are found in the more primitive members, actual or 

 hypothetical, of all the sub-classes and orders composing the 

 Class, the more modified types furnish exceptions to every state- 

 ment of the definition." This is the common experience of 



