1897 | MYELOPTERIS TOPEKENSIS 25 
more specific than generic, but my material has been so altered 
by compression that I should hesitate to place much reliance 
upon these aspects of structure, preferring rather to establish 
the affinity by means of the more perfectly preserved structural 
elements. 
The distribution of the vascular bundles in concentric zones, 
as described by Williamson, may also be a feature of the Topeka 
specimen, but for reasons already stated this cannot be asserted 
with any degree of confidence. 
More recently Solms-Laubach® has reviewed the entire 
relations of this group of plants, and while he rejects Renault’s 
name because he regards the evidence as not altogether satis- 
factory, he prefers to retain Brongniart’s name of Myeloxylon 
‘rather than Stenzelia, because it is better known.’”’ He gives 
two figures, one of a general transverse section, the other of a 
separate vascular bundle, and it is of considerable interest to 
note that this latter is almost the exact counterpart of a vascular 
bundle obtained from the Topeka fossil (fig. ¢). His general 
view of the structure is not so satisfactory, but it nevertheless 
exhibits a close similarity to my own material in all its principal 
features. 
_ Solms-Laubach dissents from the conclusions of both Renault 
and Williamson, holding that there are strong reasons, on ana- 
tomical grounds, for considering the alliance to be with the | 
Cycadacee, and cites Medullosa Leucharti as Leaf oat ae 
important evidence in support of this VIEW. a 
‘Plants is that offered by Mr 
