36 Mr R. KidwLuii u/c the 



maturity and shed all its spores, as indicated by the split 

 sporangia, whereas in the Glencartholm example the 

 lowest segment alone appears to have attained to this 

 degree of ripeness, as only on it the "' stellate" sporangia 

 are shown. 



In the course of development, we have every reason to 

 believe that during the maturation of the spike the inter- 

 nodes would become elongated ; so probably this difiference 

 in general outline is only indicative of a different state of 

 development. It agrees with Pothocites Grantonii in all 

 other respects. 



The absence of nodes on the stem of P. Grantonii seems 

 to be entirely due to changes it has undergone during 

 mineralisation. The specimen from Barnton Pavement- 

 stone Quarry has also no indication of nodes on the stem ; 

 but, from the evidence afforded by the other specimens, 

 there can remain little doubt as to both it and P. Grantonii 

 having originally possessed stems similar in this respect to 

 the other examples. 



In regard to Pothocites Pateisoni, Eth., the chief 

 characters on which this species was founded consisted in 

 the absence of the stellate sporangia and the presence of 

 the " transverse bars." I have already mentioned that 

 there are distinct indications of the stellate-like sporangia, 

 and that the degree of prominence of the transverse bars 

 depends greatly on the physical conditions under which 

 mineralisation has taken place. 



In the plant I provisionally named Pothocites calami- 

 toides the transverse bars are very distinctly seen, and 

 associated with them we have the stellate sporangia placed 

 upon their little knob-like extremities. 



For these reasons, as well as the evidence afforded by 

 the detailed descriptions of the various specimens, I believe 

 that all these fossils are to be referred to Pothocites 

 Grantonii, Paterson, and, further, that this plant is not a 

 distinct and separate species, but the fructification of a 

 species of Bornia^ Kom., probably of Bornia radiaia, 

 Brongn. 



