from the Lower Carboniferous Rocks of Pettycur (Fife). 397 



elegans or a depressed aperture as in Conostoma ovale. The 

 micropyle which lies immediately over the opening of the pollen 

 chamber is also cut tangentially and in the most radial section 

 is clearly bounded by three separate tentacle-like processes. 



The chalazal end is also interesting from the fact that the 

 bundles enter the seed independently as in Physostoma. 



This new species of Physostoma, which is more ancient than 

 P. elegans recently described by Professor Oliver, combines 

 with its Physostoma characters, others which are typical of the 

 genus Lagenostoma. The tentacular processes at the apex 

 suggest affinities with Lagenostoma in that they are less di- 

 vergent than in Physostoma (i.e. they clasp the pollen chamber 

 more tightly), and thus the seed has the whole apex flattened 

 as in Lagenostoma. On the other hand the structure of the 

 pollen chamber, so far as is known, is quite unlike that of 

 Lagenostoma. The seed may however eventually require to be 

 placed in a new genus. 



In conclusion I have to thank my supervisor Mr Arber for 

 his kindly criticism and advice. 



VOL, XV. PT. V. 



26 



