70 Bemarks on Mr. Carruihers Views of Prototaxites. 



specimens I gave to Mr. Carrutliers had been sliced and studied by 

 myself, that it is this crystalline structure which the botanist of the 

 British Museum mistakes for vegetable cells * I think it right to 

 state here that I not only gave Mr. C. specimens in these different 

 states of preservation, but that I explained to him their nature and 

 origin. 



It is unnecessary to follow further the histological part of the 

 question, as my object is not so much to expose the errors of Mr. 

 Carruthers as to illustrate the true structure of Prototaxites. 



3. Affinities. — In discussing these I must repeat that we must 

 bear in mind with what we have to deal. It is not a modern plant, 

 but a contemporary of that " prototype of gymnosperms " Aporoxij- 

 lon, and similar plants of the Devonian. Further, the comparison 

 should be not with exogens in general, or conifers in general, but 

 with Taxineae, and especially with the more ancient types of these. 

 Still further, it must be made with such wood partly altered by 

 water-soakage and decay and fossilized. These necessary prehmi- 

 naries to the question appear to have been altogether overlooked by 

 Mr. Carruthers. 



My original determination of the probable affinities of Proto- 

 taxites, as a very elementary type of taxine-tree, was based on the 

 habit of growth of the plant — its fibrous structure, its spirally-Hned 

 fibres, its medullary rays, its rings of growth, and its coaly bark, 

 along with the durable character of its wood, and its mode of occur- 

 rence; and I made reference for comparison to other Devonian 

 woods and to fossil taxine-trees. 



Mr. Carruthers prefers to compare the plant as to structure with 

 certain chlorospermous Algse, and as to size with certain gigantic 

 Melanosperms, not pretended to show similar structure. This is 

 obviously a not very scientific way of establishing affinities. But 

 let us take his grounds separately. He selects the little jointed 

 calcareous sea-weed Halimeda opuntia as an allied structure, and 

 copies from Kutzing a scarcely accurate figure of the tissue of the 

 plant as seen after removal of its calcareous matter.t He further 

 gives a defective description of this structure ; whether taken from 

 his own observation or from Kutzing, he does not say. Harvey's 

 description, which I verified several years ago, in an extensive series 

 of examinations of these calcareous Algae, undertaken in consequence 

 of a suggestion that Eozoon might have been an organism of this 

 nature, is as follows : — " After the calcareous matter of the frond has 

 been removed by acid, a spongy vegetable structure remains made 



* In fossil-woods, the carbonaceous matter, being reduced to a pulpy mass, 

 sometimes partly becomes moulded on the surfaces of hexagonal or granular 

 crystals, in such a manner as to deceive, very readily, an observer not aware of 

 this circumstance. 



f A more characteristic figure is given in Harvey's ' North American Algae.' 



