410 ilf?' Wills, Notes on the genus Schizoneura, etc. 



of the leaves into sheath-segments. Their distribution in time 

 is also of interest, for this type of ScMzoneura appears to have 

 almost died out before the advent of Neocalaniites in the Letten- 

 kohle and Lower Keuper. It may be that the one type gave 

 rise to the other, but this does not seem likely. In this con- 

 nection I would like to point out that Halle comments on 

 the resemblance and possible relationship of Neocalamites with 

 Calamites. In the same way, one may draw a comparison between 

 ScMzoneura proper and Grand'-Eury's Calamodendron type of 

 Calamite. Thus, the whorls of leaves are separated by long 

 internodes and the upper branches probably radiated out in all 

 directions, while the leaves themselves had several nerves instead 

 of a single median one, all of which facts are points of resemblance 

 between the two genera. At the same time we must recognise 

 that, until we know more about the internal structure and fructi- 

 fication of this important transitional group of the Equisetaceae, 

 the relations that they bear, both to the Calamites and to the 

 modern Equiseta, must remain a secret. 



Gonclusion. The species so far described as Schizoiieura may 

 be divided into two groups. The one has been given the name 

 Neocalamites by Halle, and includes S. carrerei, S. hoei'ensis, and 

 S. meriani. The other may be termed ScMzoneura, sensu stricto, 

 and embraces S, gondwanensis, S. africana and S. pa,radoxa. 

 Until we have more satisfactory information about S. ivardi we 

 are unable to decide to which group it belongs. 



