Renews — Dr. D. H. Scott — Studies in Fossil Botany. 569 



almost identical structure. We believe it is now recognized that 

 isolated vascular axes of Sigillaria and Lepidodendra cannot be 

 distinguished apart from the structure of the cortex and its leaf 

 cushions. 



The internal structure of the Lycopodiales is admirably described. 

 The material for the study of the Zepidodendra, being plentiful and 

 exceptionally well preserved iu the Yorkshire and Lancashire Coal- 

 field and a few other localities, has given exceptional facilities for 

 a description, which could be little more perfect had it been drawn 

 up from the living plant. The description of the internal organiza- 

 tion of Sigillaria is also good, although specimens of undoubted 

 Sigillarian stems showing structure preserved are very rarely found. 

 " The two lateral points on the surface of the leaf cushion below the 

 leaf-scar " of Lepidodendron are supposed to have some connection 

 with the parichnos. This conclusion may possibly be correct, but as 

 the point is said to have been investigated by Potonie in a Lepido- 

 phloios, where the curious structures known as the parichnos do not 

 occur on the cushion, it is probable that the specimen investigated 

 was a Lepidodendron. 



It might, perhaps, have been better if Dr. Scott had substituted 

 the name of Lepidodendron Veltheimianum for that of L. brevifolium, 

 given under the figure on p. 133, as the plant there shown really 

 belongs to that species, and especially as the cones of the same stem 

 are named Lepidostrobns Veltheimianus in figs. 67, 68, 69, and lOc-d. 

 Professor Williamson subsequently corx'ected his error in identifying 

 the Pettycur plant with Ettingshausen's Lepidodendron brevifolium, 

 which latter is a Lepidopliloios [=zLepiidopMoios acerosus, L. & H., sp.). 

 In the same lecture Lepidostrobns and Spencerites find a place ; 

 the latter, known only from its cones with curious winged spores, is 

 a most peculiar and interesting genus. 



The Ferns occupy Lectures viii and ix, and are admirably treated. 

 Here, we believe, is given the best and most concise account of the 

 structure of Palaeozoic ferns with which we are acquainted, for 

 though the space devoted to their consideration is not large, their 

 characteristics and structure are most clearly described. 



Lecture viii serves somewhat as an introduction to the study of 

 the chief fern genera and their fructifications, and concludes with 

 a description of the anatomy of Psaronius. Lecture ix is reserved 

 for the consideration of the Botryopteridae, the two forms described 

 being Zygopteris Grayi and Botryopleris hirsuta, which belong to the 

 herbaceous monostelic type of fern structure. The petioles of 

 Z. Lacattii and Z. bibractensis have long been known as common 

 fossils iu the Yorkshire and Lancashire Coal-balls. Thanks to the 

 labours of M. Eenault, in some respects Zygopteris is one of our 

 most completely known fossils, but its affinities are difficult to 

 determine, the annulate sporangia of Zygopteris and Botryopleris 

 being very different from any fructification known to occur amongst 

 recent ferns. 



The Cycadofilices occupy Lectures x and xi, and comprise one of 

 the most interesting groups of Palceozoic plants with which the 



