PALEOBOTANY AND EVOLUTION. 109 



for accurate determination and diagnosis, they have 

 occasionally been preserved in a manner far more perfect 

 than is the case with fossil animals. The hard parts of an 

 animal may be found in a wonderful state of preservation, 

 but the soft parts have at most left but a faint impression 

 of their outline, and that only in a few exceptional cases. 

 A well-known example of the impression of a soft-bodied 

 animal is that of the Cambrian Medusa, Medusites Lind- 

 stronii, Nath., from the Eophyton Sandstone of Gothland. 

 With plants, on the one hand, it is possible to investigate 

 the minutest microscopical details in the structure of the 

 most delicate tissues. Putting aside for the present all 

 those records of extinct plants, which consist simply of 

 structureless casts and fragmentary impressions, we have 

 left a mass of material which has led to something more 

 than vague suggestions and fruitless speculation. As the 

 result of the examination of petrified vegetable fragments 

 of the Permo-Carboniferous strata of England, France, 

 Germany, and other countries, contributions have been made 

 towards the solution of phylogenetic problems based on the 

 most solid foundation of fact. It is notorious that those 

 who confine their attention to living forms, have in a great 

 measure allowed their interest to be restricted within the 

 limits of existing organic types. Fossil and living plants 

 have been treated by different methods, and looked at 

 from entirely different standpoints. In recent years, how- 

 ever, botanists, as a whole, have begun to realise the im- 

 portance of a logical attitude with regard to the unity of 

 the past and present representatives of the vegetable 

 kingdom. There are now, indeed, unmistakable signs of a 

 more general recognition of the lessons to be learnt by means 

 of the better methods of palseobotanical research, and this 

 awakening interest in the investigation of extinct types is 

 likely to be considerably extended. If we endeavour to 

 take a comprehensive view of recent advances in botanical 

 science, it is difficult to ignore the fact that there are few 

 if any discoveries of more far-reaching and general im- 

 portace than those furnished by palseobotanical investiga- 

 tions. The prospect in this field of work is a particularly 



