1 66 Mr. Thomas Hick on 



practically the same structure obtains, and that in equal 

 perfection. Of these one measures T 2 T inch by Jg- inch, and 

 another, which is circular, has a diameter which is not more 

 than the latter figure. Thus in stems which range in dia 

 meter from T V to T V inch, we have the same differentiation 

 into stele and cortex, and within these an equal complexity 

 of structure. 



Another subsidiary point of some interest receives fresh 

 elucidation from these specimens, viz., the nature of the 

 lacunae, which are almost constantly present in the primary 

 vascular bundles of Catamites. Most palseobotanists now 

 accept the interpretation of Solms-Laubach that "in the 

 lacunae, or the tissue that fills them, we are dealing with the 

 tracheal initial strand of the primary bundle." 1 This 

 interpretation, however, has hitherto been based entirely 

 upon transverse sections, the author quoted pointing out, 

 that longitudinal sections bearing upon the point are 

 precarious, and " are of value only when the sculpture of the 

 walls is preserved, which is seldom the case." No such 

 sections appear to have been described hitherto, and hence 

 it seems worth while to note that the sections here dealt 

 with are exactly of the kind required, and fully confirm the 

 interpretation of the lacunae suggested by Solms-Laubach. 



These matters disposed of, we may now turn to one of 

 much greater importance, viz., the place of origin of the 

 secondary thickening and the first changes brought about 

 by the same. 



Fig. 2 represents a stem of the same type of Catamites 

 as those previously described, but it is much older, and has 

 developed a zone of secondary xylem which is nearly -V 

 inch in breadth. It was partially described by Mr. W. Cash 

 and myself many years ago 2 and has its tissues much more 



1 Fossil Botany, p. 298. 

 2 Proceedings of the Yorkshire Geological and Polytechnic Society, 1 883. 



