REVIEWS. ;35 



forms for representation, and in tlie case of diagrams or restorations, 

 pains have been taken to emphasize the more salient features. In some 

 cases, hypothetical restorations that have been since proved to be faulty 

 are altogether discarded, or in other cases are replaced by more perfect 

 ones. In fact, the aim has been to make the pictorial or visualized 

 part not less intelligible and truthful than the descriptive. 



As to the subject-matter, the arrangement and coordination is on 

 the whole philosophical and well balanced. In a work of this kind, 

 the relative importance to the palaeontologist must be the criterion 

 which governs the amount of space devoted to each group. Hence 

 certain groups which to the zoologist are of but slight interest are 

 necessarily treated in considerable detail in a palaeontologist's manual, 

 and on the other hand numerous subdivisions are passed over unnoticed 

 in the latter, which occupy an important place in zoological text- 

 books. In the original, the allotment of space was determined for 

 each class by the author, but in the translation the same ratio has not 

 been preserved, owing to variations in the amount of additional matter 

 contributed by the different collaborations. The result is that some 

 sections have been treated with greater thoroughness than others, but 

 the fault, if it be one, is rather to be commended than condemned. 

 That is, it is better that certain groups receive the painstaking revision 

 of an acknowledged expert, as in the case of the Echinoderms, Bry- 

 ozoans, or Brachiopods, than that the character of the work as a whole 

 be elevated only a little above the high standard laid down in the 

 original. 



This brings us to speak more particularly of the nature of the 

 revision which the English translation has undergone, and also of the 

 classification employed. It was originally intended to bring out a 

 strictly literal translation of von Zittel's Grundzuge der Paldontologie, 

 which should follow closely the new German edition. But palaeon- 

 tology is not a fixed science, and fresh discoveries are constantly caus- 

 ing changes and improvements in every system. Hence, to be abreast 

 of the times, a text-book must include the results of the latest authen- 

 ticated observations, and this can only be done nowadays by enlisting 

 the aid of a body of investigators scattered over the entire field of 

 science. It is to the lasting credit of Professor von Zittel, be it 

 said, that he consented to an arrangement whereby portions of his 

 newly completed treatise were parceled out to a dozen or more 

 specialists for detailed revision and enlargement ; and it also speaks 



