380 HISTORY OF GEOLOGY AND PALEONTOLOGY. 



distribution of the existing organisms and their fossil ancestors, 

 as well as many other facts, are only comprehensible on the 

 assumption of the doctrine of transmutation. 



Palaeontology has taken an active part since 1870 in the 

 establishment of the theory of descent, and at the present 

 day phylogenetic problems are regarded as one of the chief 

 charms in palaeontological research. The character of 

 palaeontological literature has been correspondingly modified ; 

 the purely stratigraphical treatment of palaeontological results 

 has been held more and more distinct from the biological- 

 systematic treatment, and the latter places the genealogical 

 direction of research more and more in the foreground. The 

 literature has been so extensively increased, and has been 

 contributed in so many different languages, and often cir- 

 culated in so few copies, that very great difficulties stand in 

 the way of obtaining a complete general survey of its results. 

 The older text-books of Bronn, D'Orbigny, Geinitz, Quenstedt, 

 Giebel, Nicholson, and others were rapidly out of date, and 

 were partially designed only to meet the requirements of 

 beginners. 



The Handbuch der Palaontologie of Karl A. von Zittel, the 

 botanical part of which was written by W. Schimper and 

 A. Schenk, endeavours to provide a general survey of 

 palaeontological subject-matter in harmony with the modern 

 standpoint of zoology. The original intention of the author 

 was to comprise Palaeozoology in one volume, but as the work 

 proceeded it extended to four thick volumes, and the 

 completion of the work occupied seventeen years (1876-93). 

 The chapter on fossil insects was contributed by S. Scudder, 

 Throughout the entire work a primary object has been to 

 point out the close relationships between palaeontology and 

 the other branches of biological science (Zoology, Comparative 

 Anatomy, Botany, Embryology), and to make application to 

 palaeontology of the data acquired by those sciences. The 

 subject-matter is therefore arranged in strict systematical order, 

 and the enumeration of each particular group of forms is 

 preceded by an introduction elucidating the main features of 

 the organisation. The histological structures are described in 

 much fuller detail than in any of the former text-books of 

 Palaeontology. In the special systematic portion, all well- 

 founded genera are accepted and described, the doubtful 

 genera are eliminated or only briefly mentioned. The 



