Seward. — The Anatomy of Lepidodendr on aculeatum, Sternb. 375 
the depression shown in Text-fig. 1, B. s, which looks like a small branch- 
scar, appears on examination of the tissues to be the result of a wound. 
The dark tissues seen at C, Fig. 5, PL XXVI, a section cut through the scar 
(Text-fig. 1, B. s), marks the position of the partially destroyed cortex and 
wound periderm. 
The external characters point to Lepidodendron aculeatum , Sternb., as 
the species with which the form of the leaf-cushions agrees most closely. 
There can at least be no doubt as to the genus to which the fragment 
belongs. The geological range of L. acideatinn in Britain is stated by 
Kidston 1 to be from the Millstone Grit to the Upper Coal-Measures. 
The transverse section, represented natural size in Fig. 5, PL XXVI, illus- 
trates the imperfect state of preservation of the slightly excentric stele, the 
tissues of which have been considerably shattered, though in places the 
structure is very clearly shown. The largest diameter of the somewhat 
flattened stele, measured from the outer edge of the xylem, reaches 1 cm. 
There is no trace of any secondary xylem ; the primary xylem consists 
of a tube of scalariform tracheids, usually about six tracheids broad, with 
narrow protoxylem-elements at the outer edge forming fairly prominent 
teeth of the single or double type (Text-fig. 2, x) as in Lepidodendron 
Harcourtii and L . fidiginosum. 
Such of the pith-tissue as remains exhibits the histological features 
usually met with in this region of lepidodendroid stems. The zone between 
1 Kidston (’ 94 ), p. 251. For figures of this species, see Zeiller (’88), PI. LXV. Figs. 1-7 ; also 
Kidston (’ 01 ), p. 44, and Zalessky (’ 04 ). 
