There has probably been some confusion in the minds of authors between sclerous tissue and dark secretory tissue in Sigillarian leaves; the crescentic band, _a_, shown in fig. 142, B, which corresponds in position with the sclerous tissue of Renault in _S. Brardi_ leaves, appears to be of the nature of secretory tissue. The diagram shown in fig. 142, B, illustrates a type of leaf very like those already described, except that there are two xylem strands, _x_. The difference between the double strand and the single bundle seen in figs. 142, A, C and 200 E, is comparatively small, but it is a real distinction. This type of leaf (fig. 142, B) was originally described by Renault[505] under the generic title _Sigillariopsis_. The genus was founded on a French petrified specimen consisting of part of a ribbed stem possessing a stele of the Sigillarian type and characterised by separate primary xylem strands, like those of _S. Brardi_ described by Brongniart in 1839. Renault considered the presence of two xylem strands in the leaf a sufficient reason for the institution of a new genus and named the specimen _Sigillariopsis Decaisnei_. Prof. Bertrand of Lille kindly photographed for me Renault’s type-specimen and sent several prints with explanatory notes. The transverse section of the leaves shows very clearly the two xylem strands; each strand consists of a triangular group of primary tracheae with the protoxylem apex pointing towards the lower surface of the lamina. Below each primary strand of centripetal xylem is an arc composed of a few small tracheae which Renault and Bertrand describe as secondary xylem; it is, however, not clear from the photomicrographs that these are of secondary origin, their position and appearance reminding one of the primary centrifugal xylem of a cycadean foliar bundle. Below this centrifugal xylem is another arc of imperfectly preserved elements described by Renault as a protective sheath and by Bertrand as glandular tissue; the latter term is probably the more correct as the tissue may well correspond to the secretory-zone tissue of Lepidodendron stems. Fairly large groups of transfusion tracheids occur on the flanks of the xylem. Prof. Bertrand points out that one of his sections, cut nearer the apex of a leaf than that figured by Renault with a single xylem strand, contains a double strand and thus shows the latter’s description to be an incorrect interpretation of the imperfectly preserved tissues. The _Sigillariopsis_ type of leaf was recognised by Scott[506] in English material on which he founded the species _Sigillariopsis sulcata_. In a section which he has recently figured[507] a lacuna below the two xylem strands is described as “representing secretory tissue”; a band of transfusion tracheae almost encircles the pair of bundles.