JB. W. Binney. 461 



Laggan Bay, afford no traces of internal structure. These last, 

 however, some of which are about two feet in diameter, afford 

 evidence of the structure of the thick inner bark, termed by me 

 the outer radiating cylinder, and the woody or inner radiating 

 cylinder of barred tubes, containing vascular bundles and 

 medullary rays, enclosing a medulla, composed of barred tubes, 

 in all respects exactly similar in structure to the large Sigillaria 

 vascularis, with irregular ribs and furrows, described by me in 

 the " Philosophical Transactions," l and the smaller specimens, 

 exhibiting on their outsides scars of Lepidodendra, described in 

 the " Quarterly Journal of the Geological Society." 2 These large 

 and small specimens gradually pass one into the other, as 

 numerous specimens in my cabinet, in addition to those figured, 

 amply testify. Many persons have become accustomed to class 

 my small specimens, the first ever described showing a medulla 

 of vascular tubes, as Lepidodendron, from their external characters, 

 without regarding their inner radiating cylinder and its singular 

 medulla, so totally different in arrangement to the vascular 

 Cylinder and medulla of orthosenchymatous tissue of Lepido- 

 dendron Harcourtii, before described in this monograph/ 



Page 1 45 '. . . When Brongniart described his Sigillaria elegans, 

 the Rev. Mr. Harcourt's Lepidodendron, Lindley and Button's 

 Stigmaria, and Mr. Witham's Anabathra, he had before him all the 

 materials then known for examining the structure of those plants 

 that the coal-measures had afforded. Subsequently Corda added 

 the Diploxylon cycadoideum. Then Goeppert described his Stig- 

 maria with the vascular bundles in the pith. But in all these 

 specimens, except the last, the structure of the piths was more or 

 less wanting. The first time that anything was published as to stems 

 with vascular tubes in their piths was in my paper in the " Quarterly 

 Journal of the Geological Society," and this was further extended 

 in my memoir in the " Philosophical Transactions," where were 

 described larger specimens of Sigillaria vascularis and Diploxylon 

 cycadoideum, all showing structure similar to that of the smaller 

 ones first described, with the exception of the Diploxylon having 

 the edges of the woody bundles of the inner radiating cylinder 



1 For 1865, p. 579 tt stq> a Vol. xviiu 1862, p, ni, 



