198 THE LATE DR. NEWELL ARBER: CRITICAL STUDIES 
Remarks on the Specimens previously figured. 
Brongniart’s type (1822), although not then described, was clearly figured, 
and the illustration on plate 15. fig. 1 b of that memoir can leave little doubt 
as to the specific nature of the specimen. The leaf bases are here rather 
small with a well-marked keel both above and below the leaf scar. The keel 
is hot ornamented. The leaf scar is situated considerably above the centre 
of the base, and is here shown as being rhomboidal in form with a single 
central print. Leaves are also seen still attached to some of the leaf bases. 
The same author’s Z. elegans and L. gracile figured in 1838, again without 
description, show precisely similar leaf bases, with the exception that in some 
cases the keel below the leaf scar is slightly but clearly notched, and that 
prints are only very rarely indicated within the leaf scar. The shape of the 
scar is, however, perfectly definite. 
Sauveur’s fig. 2 (1848) agrees very closely with the type, but again the 
species remained undescribed, — The first description of this species was 
published in 1879 by Zeiller. In the case of the cone-bearing specimen 
figured by this author, no enlarged drawing of the leaf bases is given, but it 
is clear that the leaf scar was more or less triangular in form and not slit- 
like. | 
Zeiller (1879), under the name of Lepidodendron gracile, L. et H., gives the 
first description of the plant which we here regard as L. ophiurus. This 
description, somewhat abbreviated, is as follows :— Branches slender, cushions 
rhomboidal, rather prominent, 3-4 times as long as wide, extremities acute, 
lateral angles rounded, Leaf scar placed in the uppermost quarter of the 
axis of the cushion, rather high than broad, with the upper angle rounded. 
Keel very clear, with only some very small, scarcely distinct, transverse 
folds. Lines of decurrence arising from the lateral angles of the leaf scar. 
Vascular print indistinct, placed towards the centré of the leaf scar. 
Renault’s figure, published in 1882 and referred to Lepidodendron lyco- 
podioides, Sternb., is no doubt one of the earlier stages in the confusion which 
has arisen between these two species. The leaf bases agree with those of 
Brongniart’s later figures, except that the keel is perhaps more strongly 
notched than in any examples previously figured. The usual prints of the 
leaf scar, although scarcely indicated in Renault’s drawing, are duly noticed in 
his diagnosis. We now reach the most important figures of this plant which 
have yet appeared, the illustrations so well described by Zeiller in 1886-88. 
Reserving a few remarks on his synonymy of this species for the moment, 
we may notice that Zeiller figures a definite leaf scar, which is also fully 
described in the text. Tt has a single central print. The keel of the leaf 
base is not ornamented. 
Of the specimens attributed to this species by Zalessky in 1904, the 
majority are correctly referred, though one or two appear to be examples of 
