86 THE GEOLOGICAL HISTORY OF PLANTS. 



diameter. One, two, or three contained in each sporocarp, which i?> 

 cellular. The macrospores have very thick walls with radiating tor- 

 tuous tubes. Unless this structure is a result of mineral crystallisa- 

 tion, these macrospores must have had very thick walls and must have 

 resembled in structure the thickened cells of stone fruits and of the 

 core of the pear, or the tests of the Silurian and Erian seeds known 

 as Pachytheca, though on a smaller scale. 



It is to be observed that bodies similar to these occur in the Bog- 

 head earthy bitumen, and have been described by Credner. 



I have found similar bodies in the so-called " Stellar coal " of the 

 coal district of Pictou, Nova Scotia, some layers of which are filled 

 with them. They occur in groups or patches, which seem to be en- 

 closed in a smooth and thin membrane or sporocarp. It is quite 

 likely that these bodies are generically distinct from Protosalvinia. 



5. Protosalvinia punctata, Newton, " Geological Magazine," New 

 Series, December 2d, vol. ii. Mr. Newton has named the discs 

 found in the white coal and Tasmanite, Tasmanites, the species be- 

 ing Tasmanites punctatus, but as my name Sporangites had priority, 

 I do not think it necessary to adopt this term, though there can be 

 little doubt that these organisms are of similar character. The same 

 remark may be made with reference to the bodies described by Hux- 

 ley and Newton as occurring in the Better-bed coal. 



In Witham's " Internal Structure of Fossil Vegetables," 1833, 

 Plate XI, are figures of Lancashire cannel which shows Sporangites of 

 the type of those in the Erian shales. Quekett, in his " Report on the 

 Torbane Hill Mineral," 1854, has very well figured similar structures 

 from the Methel coal and the Lesmahagow cannel coal. These are 

 the earliest publications on the subject known to me ; and Quekett, 

 though not understanding the nature of the bodies he observed, 

 holds that they are a usual ingredient in cannel coals. 



II. THE NATURE AND AFFINITIES OF PTILOPHYTON. 



(Lycopodites Vanuxemii of "Report on Devonian and Upper 

 Silurian Plants," Part I., page 35. L. plumula of " Report on Lower 

 Carboniferous Plants," page 24, Plate I., Figs. 7, 8, 9.) In the re- 

 ports above referred to, these remarkable pinnate, frond-like objects 

 were referred to the genus Lycopodites, as had been done by Goep- 

 pert in his description of the European species Lycopodites pennm- 

 formis, which is very near to the American Erian form. Since 1871, 

 however, there have been many new specimens obtained, and veiy 

 various opinions expressed as to their affinities. While Hall has 

 named some of them Plumalina, and has regarded them as animal 



