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EDITOR'S PEEFACE TO THE SECOND EDITION 



A NEW Eiiglish editioii of von Zittel's Text-hook of Paleontology having been 

 called for, advantage was taken of the opportunity to prepare a thorough- 

 going revision of the first volume, in order that an adequate account might 

 be incorporated of the new knowledge that has been gained during recent 

 years. 



Towards this end, a number of specialists were invited to collaborate with 

 the Editor in preparing a fresh treatment of the leading groiips of Inverte- 

 brates, and the present work bears witness to the generous response that was 

 made to this invitation. Many parts of the work have been entirely re- 

 written, others have been emended, rearranged and enlarged, and the 

 Classification in various places has been very considerably altered. The new 

 work, therefore, cannot with either justice or propriety be called von 

 Zittel's Text-book, being in effect a composite production ; and yet in scope 

 nd style it is modelled after the well-known German original. 



The names of the diflerent collaborators appear on the title-page, and the 



ections that have been revised or rewritten are credited in the body of the 



work to the specialists responsible for them. To all of his collaborators 



the Editor desires to offer grateful acknowledgments, and to express the 



sense of his owii joersonal indebtedness to them for the large service they have 



endered, and for many individual courtesies. 



To his friend and former associate at Harvard, Doctor Eobert Tracy 

 ackson, the Editor is under an Obligation greater than can be adequately 

 icknowledged ; for besides having contributed practically a fresh account of 

 he Echini, Dr. Jackson has carefully read the proofs of the entire work, and 

 as offered in many places most valuable suggestions and emendations. Like 

 everal of the other collaborators, also, he has furnished the Originals for a 

 umber of new figures. The total number of fresh illustrations has thus been 

 ensibly increased. It is hoped that the large amount of painstaking work 

 hich has been bestowed upon the present treatise will be found to yield 

 eturns in increased value and usefulness among students of Paleontology 

 generally. 



CHARLES R. EASTMAN. 



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Carnegie Museum, Pittsburgh, 

 Pennsylvania, June 5, 1913. 



Al'i'S 



