Structure of Lejpidodendron and Sigillaria. 131 



Figs, 2, 5, are intermediate forms. Prof. Schimper thinks 

 that 8. Menardi is a branch of S. Brardii. A comparison of 

 specimens of these forms confims in my mind their specific 

 identity. But all the specimens of 8. Brardii,which. I have seen, 

 are themselves fragments of branches, $. lepidodendrifolia 

 being doubtless the trunk. The gradual obliteration of the 

 leaf-bases of 8. JBrardii, and the blending of the form with 

 8. lepidodendrifolia, can be traced in numerous specimens. 



The vascular scars of 8. Brardii are identical with those of 

 8. lepidodendrifolia, the probable typical form being shown in 

 Kg. 5. 



8, Serlii, Brongt., is probably but another variation of this 

 compressed form of 8. lepidodendrifolia, as Prof. Schimper has 

 suggested. Its chief peculiarity is the minuteness of the vas- 

 cular scars ; but these are a very variable and. with a few 

 specimens, an unreliable feature. 



If the* scars of 8. Defraneii, Brongt., were somewhat 

 smaller, 1 should affirm, without hesitation, that the figure is 

 inverted, and the form identical with my Fig. 5. I am still 

 very confident that this is the case. Scars of 8. Brardii are 

 frequently larger; and there can be no reason why scars 

 slightly more compressed, and in a little different manner, 

 should not be quite as large. The vascular scars of 8. Defran- 

 eii are represented as about in the middle of the leaf -scars, or, 

 if we invert the figure, as sometimes slightly below the centre. 

 It seems to me not impossible that this is an unconscious error 

 of the draughtman's, produced by inverting the fossil, he 

 knowing that the vascular scars are usually, if not always, more 

 or less above the centre of the leaf-scar. However, the form 

 as figured may be erect and still be compressed 8. Brardii* 



8. rhomboidea, Brongt., and 8. obliaua, Brongt., which 



*Note : Since writing the above, I find that M. Grand'Eury, in his recent 

 ■work, " Flore Carbonifere du department de la Loire et du centre de la 

 France, " makes 8. Defraneii a variety of 8. Brardii. 



In common with other palaeontologists, he includes 8. Brardii in the sub- 

 genus Olathraria, and 8. lepidodendrifolia in Leioderma : but admits that the 

 types are connected by numerous transitional forms. 



