358 THE NATUEAL HISTORY EEVIEW, 



Opisthohranchiay with the completion of which Professor Bronn's 

 work ceases ; Heteropoda ; Prosohranchia, and Pulmonata. "We may 

 note here that Dr. Keferstein has abandoned the arrangement of the 

 Synopsis of genera in a tabular form, a plan which was adopted by 

 Professor Bronn throughout his portion of the work ; and also that 

 he devotes a great deal of space to the geographical distribution, 

 which is discussed in great detail. 



It will be seen that, with the exception of the classification of 

 some parts of the Actinozoa, the chief objections that we have to 

 urge against this valuable work relate only to minor points, and that 

 they are such as very slightly detract from its usefulness to those 

 advanced zoological students for whose behalf it has evidently been 

 prepared. "When we set against these defects the evidences of 

 care in the compilation of the accounts of the different classes, and 

 the copiousness of the details given upon all points of the structure 

 and life-history of the animals composing them, the faults retire still 

 further into the background, and we are impressed solely with the 

 great excellence of the work, and with a sense of the gigantic labour 

 which must have been required to bring together such a mass of 

 material, and to arrange it in so convenient a form. As a Textbook 

 of recent and fossil Zoology it is, and will probably long remain, with- 

 out a rival. 



We have hitherto spoken only of the literary portion of this work, 

 but its illustrations require some notice, as indeed might be expected 

 from the statement on the title page. The pictorial department of 

 these volumes seems to us to be deserving of all praise ; the figures, 

 although perhaps sometimes not quite so delicate as those with which 

 the special w^orks of naturalists are illustrated, are nevertheless 

 admirably executed, and constitute unquestionably the grandest 

 body of illustrations with which any scientific Textbook was ever 

 adorned. The plates, which are lithographed, are exceedingly 

 numerous, and furnish illustrations, generally copied from those of 

 the best authorities, of all the points in the structure and develop- 

 mental history of the animals which are most characteristic of the 

 difl'erent classes and subordinate groups, and also representations of 

 the external form and appearance of the most typical genera. The 

 figures of generic types are referred to in the tables of genera, and 

 thus the student will be enabled by the aid of this book alone, to 

 determine a vast number of the animals which are most likely to 

 occiQ' to him in his investigations. 



