110 Mr Thomas, On some new and rare Jurassic plants, ete. 
theories and involves fewer assumptions than do the contrary | 
views. These unisexual flowers may have originated from bisexual | 
flowers, and the form Wielandiella which has been described by 
Prof. Nathorst* doubtless indicates a stage in reduction of a 
completely bisexual flower to one in which the ovulate portion 
only was fully developed, the microsporophylls being very much 
reduced and delayed in development. I therefore regard the 
structure which has been described above as an independent male 
flower of Walliamsonia gigas (L. and H.). 
In conclusion I must express my best thanks to Dr Pelourde of 
the Paris Museum for his kindness in enabling me to study and — 
photograph the specimen, and to Prof. Seward to whose encourage- 
ment the appearance of this note is due. 
DESCRIPTION OF FIGURES. 
Puate VI. 
Fig. 1. Specimen of male flower of W. gigas in the Yates collection, 
Natural History Museum, Paris. Photographed from one side showing 
basal part of united sporophylls, and on the right ue above, the 
region in which the synangia were borne, cf. text-fig. 
Fig. 2. Photograph of the same specimen from below, ae circular 
outline of cup. The base is not distinctly seen, but the sporophylls 
each with a central row of large depressions are seen on the left 
side. 
* « Palaobotanische,” Mitteilungen 8. ibid. 
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