222 me. a. c. sewaed on the [May 1903, 



Dictyozamites Jolmstrupi is characterized by the more strongly- 

 curved pinnae, with more sharply-pointed apices, and by their 

 manner of attachment to the rachis. 



PI. XY, fig. 1. This specimen shows clearly the crowded arrange- 

 ment of the pinna?, and their manner of attachment to the axis of 

 the frond. The upper face of the rachis is hidden by the bases of 

 the pinnae, as in the frond of Otozamites. The upper edge of the 

 pinna-base is distinctly auriculate, while the lower edge appears to 

 be merely rounded or very slightly lobed. The most complete 

 pinna is 3 centimetres long and 11 millimetres broad ; in the 

 venation-characters the species agrees with the other types of the 

 genus. 



Pig. 2. This drawing gives an end-view of the lowest pinna 

 of the specimen represented in fig. 1, and shows the small and 

 narrow oval area a by which the leaflet was attached to the 

 surface of the rachis r, agreeing in this respect with the method of 

 articulation of the pinnae of EncepKalartos and certain other recent 

 Cycads. The scar or attachment-area, a, is situated slightly below 

 the middle of the pinna-base. 



Pig. 3. In this fragment the venation is shown with great 

 clearness ; the most complete pinna has a length of 3-8 centimetres, 

 tapering gradually towards the bluntly rounded apex. 



Pig. 4. This enlarged drawing of a portion of one of the pinnae 

 shown in fig. 3 illustrates the characteristic venation of the genus. 



Dictyozamites falcatus (Morr.). (PI. XY, figs. 5-8.) 



Pig. 5 represents a portion of a frond, drawn three times natural 

 size, showing the form and manner of attachment of the bases of 

 the pinnae. 



Pigs. 6 & 7 illustrate the short, broad, and slightly-falcate form 

 of the pinnae of a small type of the Indian species. Pig. 7 is 

 drawn natural size. 



Pig. 8. A single pinn#. enlarged to show the venation, which 

 agrees closely with that of Dictyozamites Hawelli. 



Comparison of the Japanese, Indian, Bornholm, and 

 Pnglish Mesozoic Ploras. 



It is of interest to compare the Mesozoic floras of Japan, India, 

 Bornholm, and England, in each of which Dictyozamites is repre- 

 sented. The resemblance of one flora to another is usually obscured 

 by the use of different generic or specific names for plants, which 

 are either identical, or represent closely-allied members of the same 

 family. This diversity in nomenclature is, to some extent, the 

 result of geographical separation ; an author naturally hesitates to 

 assign the same specific name to plants from India and Europe 

 unless the evidence as to identity is convincing. On the other 

 hand, wide separation in space has often been allowed to exercise 

 a misleading influence in the determination of species. Another 



