288 Mr Thomas, On a specimen of the cone, etc. 



hitherto remained unknown. The leaves have now been dis- 

 covered, and there is little doubt that, before long, a petrified 

 stem bearing leaves of this kind will be found. The " annulus " 

 and the hairs on the stem are here described for the first time. 



The great similarity of structure between the foliage leaves 

 and the bracts of the cone is also a point of some interest, as 

 indicating the foliar nature of the latter. This, together with 

 the probable occurrence of an annulus in Calamostachys, is of 

 some importance in the discussion of the morphology of the cones 

 of the Equisetales. 



My best thanks are due to Mr Arber for his kind advice and 

 assistance in this work. 



