Nematoph>jcus or Prototaxites 1 209 



be correct ; and Dr. Dawson fairly meets the question when he 

 says, " that Mr. Carruthers' figure (Plate XXXII.) is, in my judg- 

 ment, to a great extent imaginary." 



To prevent my opinion of the nature of the structure influ- 

 encing the artist in his \York, I departed from my usual custom of 

 having the plates executed under my direction in the Museum, and 

 gave the specimens to Mr. Blair that he might put on the stone 

 just what he saw. In a letter from Mr. Blair, maintaining the 

 accuracy of drawing and truthfulness of eflect of his plates, he says, 

 " As I did not make the drawings at the Museum under your di- 

 rection, they were uninfluenced by any views you entertained on 

 the subject." Before publication I carefully compared the plates, 

 with the portions of the fossil drawn, and I am satisfied that Mr. 

 Blair has rendered them with singular fidehty and accuracy.* 



But the trustworthiness of Mr. Blair's drawings is put beyond 

 doubt from the testimony of skilled and distinguished investigators 

 who have examined this fossil, and to whom I referred at the close 

 of my memoir. Mr. Archer, of Dubhn, has again examined the 

 specimens, and published at greater length than before his view^s 

 regarding them, which are based on the existence of the two kinds 

 of tissue. He thus sums up his estimate : — " If the large tubes 

 showed septa at regular, in place of at very remote intervals, if at 

 all, there would be much to call in mind a ' mass ' of a Ccenogo- 

 luum-Yike character — that is, large filaments running longitudinally, 

 with an intervening hypha-like tela contexta, as it were, binding 

 them together."t This and the similar testimonies of Prof. Dickie, 

 of Aberdeen, and Prof. Agardh, of Lund, the first living algologist, 

 who have also examined the specimens, may be nothing to Dr. 

 Dawson, but they will carry conviction to all who are able to esti- 

 mate evidence as to the accuracy of Mr. Blair's plates, and the cor- 

 rectness of my account of Nematophyciis. 



I regret that Dr. Dawson should feel so much " the tone and 

 manner " of my paper. I endeavoured to avoid whatever would be 

 unne<!essarily objectionable to Dr. Dawson, but in a paper which was 

 so completely destructive of his repeatedly published errors I could 

 not expect to please him. Dr. Dawson compelled me to deal with the 

 subject, as he had himself published in an imperfect and unsatisfactory 

 manner opinions I had communicated to him in correspondence, and 

 had then criticized these imperfectly-expressed views and set them 

 aside. In stating at length my views of the structure and affinities 

 of the fossil I used plain expressions, which the botanical reader 



* If any reader is sufficiently interested iu this matter to examine the speci- 

 mens, they can at any time be seen, iis tliey form part of the extensive collection 

 of fossil plants prepared for microscopic investigation, belonging to the Botanical 

 Department of tlie British ISIiisium. 



t • Quart. Jouru. Micr. !^c.,' July, lS7o, p. olo. 



