44 M. YOKOHAMA. 



appears to have been entire-margined with a comparatively weak 

 midrib. The leaf has been flatly pressed on to the stone, and the 

 venation is almost wholly defaced. By a careful examination, how- 

 ever, it exhibits faint traces of delicate parallel veins perpendicular to 

 the rhachis ; and as the blade seems to lie upon the rhachis, our speci- 

 men is probably referable to Nilssonia. A positive determination 

 however must be postponed until better specimens are discovered. 



3. Dioonites Bomem. 



28. Dioonites Kotoei m. 

 VI VII, fig. la, b, c, le. VI XIV, fig. 14. 



Leaf pinnated ; segments opposite or alternate, lightly curved and 

 more or less directed forward, long, linear-lanceolate, acute, inserted on 

 the rhachis with the whole base; veins fine, equal, parallel, 7-14 in 

 number. 



Segments of this species vary much in length and breadth, but 

 are commonly 7-9 times as long as broad, and broadest.uit base. The 

 longest segment in our specimens measures 4^ mm. in breadth and 

 33 mm. in length, with apex a little broken off. The segments are 

 in most cases quite separate from one another; but sometimes a little 

 contiguous. Their directions are not always the same, some being 

 directed more acutely forward than others, some being tolerably 

 falcate in shape, while others are more straight. Veins are delicate, 

 and rise perpendicular to the rhachis (fig. le enlarged). 



Very closely akin to Dioonites Bronguiarti Schenk (Flora der 

 nordwe st deutsch. Wecddenform., p. 336, pi. XXXII, fig. 2, 2a) from 

 the Wealden of Germany, from which however the Japanese form is 

 distinguished in having longer segments traversed by a greater num- 

 ber of veins (in I). Bronguiarti, 5-6). Our fossil may also be com- 



