223 PROF. F. E. WEISS ON A BISERIATE HALONIAL 
were cut from it was carefully preserved by Williamson and is described in his Catalogue, 
under No. 1949 A, as ** part of the original specimen preserved to show one of the large 
halonial tubercles.” This piece, so judiciously preserved by Williamson, shows this 
remaining tubercle very clearly. Another piece of this branch was preserved by 
Mr. Wilde, and is now in the Wilde Collection at the Manchester Museum. This piece, 
from which the central portion of the axis has disappeared, consists of the outer portion 
of the nodule with the leaf-bases and part of the cortex preserved. It shows three large 
scars in vertical series, which were no doubt three of the zz ulodendroid ” scars. 
The importance of this specimen lies in the preservation of the leaves, from which there 
is no doubt that the plant was referable to the genus .Lepidophloios; and hence we have 
in this case, too, a fruiting-branch of Lepidophloios fuliginosus in which the cones were 
attached in two vertical rows. We see therefore that Williamson has in this case 
described a Lepidophloios with biseriate halonial tubercles. 
In the case of the specimen (cabinet-number 379) figured by Williamson (1881) in his 
XIth Memoir (fig. 9), and for which he at first retained the name of Lepidodendron 
Harcourtii (see Proc. Royal Soc. vol. xlii. 1887), but which he subsequently transferred to 
L. fuliginosum (see his General and Morph. Index, Part II. p. 13, 1893), we have un- 
doubtedly an halonial stem giving off a branch from the central vascular cylinder to an 
halonial tubercle, as Williamson himself thought was the case (p. 200). "The elliptical 
shape of the stele and its general similarity in the mode of branching with that in 
Lomax's specimen would seem to point out that here also we have two rows of tubercles. 
If this should be the case, we shall have another instance of a biseriate halonial branch 
belonging to the genus Lepidophloios. 
The consideration of the above-mentioned specimens of biseriate halonial branches 
shows that such branches may be referred to the genus Lepidophloios in some cases by 
their external markings, in other cases on the strength of their internal structure. 
These instances therefore support the view put forward with regard to the Hough Hill 
halonial branch now under consideration, that it is the fruiting-branch of Lepidophloios 
Juliginosus. This view is of course opposed to Kidston's definition of Halonia; for he 
considers halonial branches to be characterized by multiseriate tubercles, and these 
only to be referable to the genus Lepidophloios, and he does not recognize the “ biserial 
Halonias" of D’Arcy Thompson (1880). The biseriate arrangement Kidston considers to 
be the ulodendroid fruiting-branch of Bothrodendron, Sigillaria, or Lepidodendron. He 
would tberefore refer the specimen forming the subject of this paper, as he has done the 
-Halonia disticha described and figured by Morris (1840) in Prestwich's account of the 
geology of Coalbrookdale, to Sigillaria discophora. ln Morriss Halonia, however, 
neither the leaf-bases nor the internal structure is preserved, whereas in the present 
specimen the internal structure is undeniably that of Lepidophloios, as will be readily 
seen from the detailed account of its anatomical structure which follows. 
