ON LEPIDOPHLOIOS SCOTTII. 451 



This tissue does not seem to have had any communication with the exterior other 

 than on the leaf-scar. The examination of a large number of leaf-bases cut in all 

 directions has failed to show any such connection either directly or by pits, as in the 

 Lepidodendrons ; indeed, the parichnos is much the same distance from the exterior at 

 all parts of its course in the leaf-base, until it emerges on the leaf-scar. 



Fig. 14 shows a radial section of a leaf- base, with parichnos strand (par.), leaf-scar 

 (l.s.), ligulepitand ligule (Ig). The section just misses the ligule canal, which was prob- 

 ably slightly bent to one side in this case, as all other radial sections show the canal as 

 well. The point where the leaf-base ceases to be keeled and becomes round is well 

 shown in this figure, as also in fig. 10, c.d., while in fig. 7 the difference in transverse 

 section is well marked. Fig. 7 is part of a section cut sloping outwards, so that the 

 difference might be seen ; in the lower part of the figure the leaf-bases are keeled ; in the 

 upper part they are rounded. As the lower part is nearer the stem than the upper, the 

 leaf-bases are keeled near the stem and rounded near the leaf-scar. 



The leaf-scar is slightly hollow, due probably to contraction of the tissue after the 

 foliage had rotted away, and the leaf-trace shows as a low papilla in this hollow, about 

 one-third of the height of the scar from the bottom. 



The branching in all the cases examined was of unequal dichotomy, but apparently 

 of two types. In most cases the wood ring is not broken, only the outer elements 

 passing off to form the branch ; but in fig. 6 the ring is ruptured, and the pith cells 

 are seen growing out through the gap. This last type is also seen in transverse section 

 in specimens in my own and in Dr Kidston's collections. The branches, however, are 

 all alike devoid of a pith, and are representative of the " halonial" type of branch.'" 



In my specimens the branches project very slightly beyond the covering of 

 leaf-bases, where they are broken over, and they seem to have been quincuncially 

 arranged. In one series of longitudinal sections 1 inch long, there are four of these 

 branches, so that they are set somewhat closely together ; they are not in vertical rows. 

 In all cases they are sharply broken off outside the leaf-bases, and they taper quickly to 

 this truncation. The leaf-bases do not form rosettes round these tubercles, as is 

 characteristic of Lepidophloios Scoticus (Kidston). 



This new species has points in common with other species. The occurrence, for 

 example, of short tracheides in and round the pith suggests comparison with Lepido- 

 dendron vasculare (Binney, sp.) and L. Hickii (Watson), but the leaf-bases in these 

 species at once differentiate them from Lepidophloios. The only species with which more 

 careful comparison is necessary is Lepidophloios Scoticus (Kidston), and Lepidodendron 

 Pettycurensc (Kidston). The latter was described from the woody axis only, and the 

 complete absence of any pith in that species is sufficient to distinguish it from 

 Lepidophloios Scott it. Lepidophloios Scoticus is very common through the whole 

 Calciferous Sandstone series in carbonised impressions, and, from the similarity of leaf- 

 base, L. Scottii might easily be mistaken for L. Scoticus. Comparison is therefore very 



* Mr Lomax, who prepared the sections of Dr Scott's specimen, referred to it as a halonia-hke stem. 

 TRANS. ROY. SOG. ED1N., VOL. XLVI. PART III. (NO. 19). 69 



