6o6 THE AMERICAX XATURALIST. [Vol. XXXVI II. 



be said that the latter fully maintains the high standard set in the 

 earlier portion of the work. The present volume treats of the Ver- 

 tebrates, with the exception of the mammalia, to the consideration of 

 which class the third and last volume will be devoted. 



The general method of treatment which has made Zittel's works 

 so valuable to the student happily has been closely adhered to in 

 the translation ; we refer especially to the introductory sections on 

 the various classes, and to the brief diagnosis in italics with which 

 the consideration of each group, — class, sub-class, order and family, 

 — is introduced. It is largely to this latter feature that these works 

 owe their superiority as books for ready reference. 



In comparing the English edition with the original we note first 

 very considerable amplification and revision, representing the ad- 

 vance in Palaozoology during the seven years since the publication 

 of the earlier work, and in this enlargement and revision Dr. East- 

 man has had the collaboration not only of the author but of a num- 

 ber of competent English and American specialists. As regards 

 Taxonomy the changes from the original have been very slight, far 

 less indeed than we had hoped to see, and it is to be regretted that 

 the editor and his collaborators so far subordinated their own views 

 on classification to those of the author, since some rearrangement, 

 especially of the fishes and reptiles, was quite desirable. 



The entire section on fishes has been translated and revised by 

 Dr. Arthur Smith Woodward of the British Museum. Dr. Wood- 

 ward has been rather conservative in the matter of revision and has 

 kept his own opinions on taxonomic points very much in the back- 

 ground. Of this section the part on ostracoderms has undergone 

 the most extensive revision, chiefly based on the recent researches of 

 Traquair. Thus we find Traquair's order Anaspida included, and in 

 all nine families of ostracoderms are recognized. The Arthrodira, 

 which in the original were given ordinal rank among ostracoderms, 

 are now very properly placed as a sub-class, but the Macropetalich- 

 thyds— the Anarthrodira of Dean — are ranked incertce sedis. It is 

 rather to be regretted that the old division of the bony fishes into 

 Ganoidei and Teleostei has been adhered to, instead of the better 

 morphological differentiation of Crossopterygia and Actinopterygia. 

 The old system has, however, the merit of familiarity and conven- 

 ience. The section on ganoids has been amplified about one half 

 and has been thoroughly revised. Little is said regarding the sys- 

 tematic position of the Dipnoi, but we can scarcely approve of their 

 place in the book, in immediate sequence to the Arthrodires ; it sug- 

 gests tacitly the former supposed relationship of the two groups. 



