54 SCIENCE PROGRESS. 



appears in such various forms and positions in cortical 

 tissues of various other Lycopodinous plants ". l 



To quote, in conclusion, one more sentence from this 

 paper: "All these considerations serve to draw the 

 Lycopodinous plants of the present and the past more 

 closely together as a natural family, while it is interesting 

 to note that the lines of similarity as regards structure, 

 form, heterospory and details of sporangia do not locus 

 themselves specially between any two genera, but are such 

 as to suggest complex cross-relationship between the several 

 representatives of this very natural series ". 2 



It frequently happens that in cases where we have 

 been able to learn a good deal from specimens showing 

 internal structure, about the histological characters of 

 Coal- Measure plants, we are left without any precise 

 acquaintance with the external appearance of the plants 

 to which the mineralised fragments belonged. From time 

 to time, however, additional specimens are brought to light 

 which enable the pala^obotanist to arrive at a fairly complete 

 idea, not only of the histological characters but also of the 

 gross anatomy, of individual species. A recent communi- 

 cation from Prof. Zeiller of Paris affords an exceptionally 

 interesting case in point. 3 



In 1871, Williamson published a description of a strobilus 

 from the Lancashire Coal- Measures, to which he gave the 

 name of Volkmannia Dawsoni, at the same time suggesting 

 a probable affinity to Asterophyllites or Sphenophyllum} 



In 1884, the late Prof. Weiss of Berlin proposed to 

 substitute for Volkmannia Binney's genus Bowmannites? a 

 proposal which is accepted by Williamson in his memoir of 

 i890. c Again, in 1891, 7 we have a much more complete 



1 Anna/s Bot., loc. cit., p. 349. 



2 Loc. at., p. 351. 



s Mem. Soc. Geo/., France. Pal. Mem. ii., 1893. 



4 Mem. Lit. Phil., Manchester, vol. v., series iii., 187 1, p. 2S. 



8 Abh. geol. Specialkarte Preuss., v., p. 286. 



6 Phil. Trans., vol. clxxxi., 1890, B, p. 99. 



7 Ibid., vol. clxxxii., 1891, B, p. 255. 



