315 



The former material is a pièce of carbonate of lime, in 

 which besides the Psilophyton-stems there were some shells 

 of Primita spec. and also a scale of a Placoderm, Psilo- 

 phyton thus being associated with marine fossils. It was 

 from the Devonian strata of Canada, I do not know 

 exactly where ^). The Psilophyton-stems were of two kinds ; 

 some of them were slender, about l^l^ mM. broad, devoid 

 of spines; others were broader, — 4mM., with conspicuous 

 spreading sometimes reciîrved spines. On the top of one 

 the stems the spines were closely arranged. They were 

 treated with Eau de Javelle, which gave a better resuit 

 than Schultze's macération liquid; with the latter liquid 

 the pièces of charbonised matter retained their dark colour, 

 became brittle and crumbled to pièces. I found the coUo- 

 dium method a great advantage; the well cleaned fossil 

 was treated with a little of the coUodium solution ; after 

 a short time the thin membrane could be removed and 

 with it the often very small pièces of charbonised substance 

 adhering to it. 



This membrane was then placed in the bleaching solu- 

 tion, and as the collodium holds the particles together 

 they are more easily handled and are less exposed to 

 damage. 



After 5 days in the liquid they were sufRciently cleared 

 up for microscopical investigation. In some of them it was 

 not possible to find any structure, in others many détails 

 were visible. Thèse are well shown in a fragment about 

 2 mM. broad, of one of the smaller branchlets, which 

 was removed as a whole from the substrate. It was possible 

 with a needle to remove the cuticle from one side of the 

 minerai substance, which occupied the space between the 



^) On the label was written : Devonian, Crustacean, Scumenac, Canada. 

 I am much indebted to Prof. Dr. ]. H. Bon ne m a, who kindly placed 

 the material at my disposai. 



