256 Mr. E. Kidston on the Relatioyiship 



genus Bothrodendron^ for, under the name of Halonia punc- 

 tata, he includes different plants. 



Lepidodendron salehrosum and Sigillaria perplexa, Wood, 

 are only fragments of Sigillaria discophora. 



Both in Sigillaria perplexa and in the figure given under 

 the name of Sigillaria Menardi by Lesquereux, the longitu- 

 dinal clefts which appear in the bark of old examples are well 

 seen. A similar vertical splitting of the bark also takes place 

 in the succeeding species {Sigillaria Taylori, Carruthers, sp.), 

 and has already been pointed out as occurring in Lepidodendron 

 Ve liheim ianum . 



One of the most interesting figures of this species has been 

 given by Romer in the ' Palseontographica,' vol. ix. pi. xii. 

 fig. 7, under the name of Sigillaria JPreuiana. He says of 

 his plant, on p. 42 : — " The leaf-cushions stand, as in Lepido- 

 dendron, in oblique rows ; they are rhomboidal or six-sided, 

 as long as broad, slightly elevated_, and show above the 

 middle a round scar, on each side of which are two semilunar 

 scars. The leaf-scar is almost as large as the leaf-cushion." 

 I have seen many well-preserved specimens of Sigillaria 

 discophora with the leaf-scars identical with those described 

 by Romer as occurring in his Sigillaria Preuiana, and were 

 it not for the presence of the large Ulodendroid scars on these 

 specimens they could not have been distinguished from 

 Romer's plant. Hence, as Sigillaria Preuiana agrees in 

 all the characters that it shows with undoubted specimens of 

 Sigillaria discophora we have no course left but to unite these 

 two species. Portions of some of those examples of Sigillaria 

 discophora, to which I have referred, might be broken off from 

 those parts where the large scars do not occur and would be 

 undistinguishable from Sigillaria Preuiana, Romer. I am 

 also strongly inclined to think that Lepidodendron pustulatum, 

 Boulay *, is not specifically distinct from Sigillaria disco- 

 phora, Konig, sp. Sigillaria discophora appears to be re- 

 stricted to the Coal-measures. 



Localities and Horizons. 

 Scotland — Coal-measures. 



Ayrshire : Bonnington Pit, Kilmarnock [Rev. D. Lands- 

 horough. 



Clackmannanshire: Devonside, Tillicoultry {T. Mitchell) ; 

 Furnace Bank Colliery, Old Sauchie. 



Lanarkshire : " Airdrie Coal Field " [Huyiterian Museum, 

 Glasgow) ; near Carluke [collection of British Mu- 

 seum) ; Shotts [ditto) ; Shettleston [R. Dunlop). 



Perthshire : Blairingone Colliery, 1| mile S.E. of Dollar. 



* Boulay, Le terr. liouil. du nord de la France et ses vegiSt. foss. p. 37, 

 pi. ii. figs. 2, 2 bis. Lille, 1876. 



