84 CORRESPONDENCE. 



that of microscopic structure, he contents himself with assertion, and 

 with citing witnesses who have had no communication respecting the 

 matter except with himself. In answer I can only repeat the statement 

 of my confident belief in the accuracy of my own observations. 

 Vegetable histology has been with me an almost life-long study, more 

 especially in its application to the structures of fossil plants ; and long 

 practice in examining them in all states of preservation and prepared 

 by various methods, has given me too much confidence in my own 

 results to allow me to defer to the opinions of observers of less 

 experience in this special department. More especially must this be 

 the case when their own statements render it plain, as I pointed out 

 in my former communication, that they have not had distinctly before 

 their minds the gradations of palaeozoic structures, and of disintegra- 

 tion of woody tissues which serve to bridge over the space between 

 modern gymnosperms and such organisms as Prototaxites. The 

 materials to illustrate this exist in my own cabinet ; but it would 

 require a long memoir and many engravings adequately to inform 

 those who have not gone over the series of recent and fossil woods that 

 led me to understand Prototaxites, and thereby to enlarge our views 

 as to the range of structure of the more ancient land plants, and as I 

 hope to pave the way for the discovery of yet more strange and 

 elementary forms in the Silurian flora yet to be discovered. Time 

 and means to give such illustrations are both wanting at present, and 

 new facts and specimens are urgently calling for investigation. 



Lastly, as Mr. Carruthers volunteers to exhibit and explain the 

 specimens which (I fear too incautiously) I presented to the British 

 Museum, allow me to say that I would prefer to take this duty on 

 myself, and to furnish to anyone who may take the trouble to study 

 this remarkable plant, typical specimens, and also some material for 

 comparison. 



Yours truly, 

 J. W. Dawson. 



Teiceratium fimbriatum, Wall. 



To t/ie Editor of the ^Monthly Microscopical Journal.^ 



Forest Rise, Lettonstone, January 3, 1874. 

 Sib, — Having just now opened the September number of your 

 Journal, I find at page 137 some remarks on this species by Dr. Arthur 

 Mead Edwards, a well-known diatomist, occasioned by a paper by 

 Dr. Woodward in the ' Lens ' for April, 1872. I have not seen this 

 number of the ' Lens,' nor consequently the figiires in Dr. Woodward's 

 plate on which his remarks are founded. I am surprised, however, to 

 find that Dr. Edwards comes to the conclusion that this species should 

 be rejected, and united with Trie, favus, Ehr., and I cannot but think 

 he has formed his opinion on insufficient data. I grant him that Ealfs 

 has made Trie, finihr latum a synonym of Trie, favus (' Prit. Inf.,' 1861, 

 p. 855), and so has Eabenhorst (' Eur. Flor. Alg.,' 1864, p. 315), but 

 notwithstanding these authoiities and my strong inclination to tinite 

 rather than to multiply species, I still venture the ojjinion that the 

 species are distinct, and that the difference in the valves can be at 



