Ferieics — Seward's Mesozoic Plants. 275 



divided between the Pteridophytes and the Gymnosperras, Angin- 

 spenns being so far entirely unrepresented, as is still the case even 

 in the more recent Wealclen beds. 



Under the Equisetacea? two species of Equisetites are described, 

 plants wonderfully similar in aspect to the recent Horsetails, but 

 often of enormous dimensions, E. Beani attaining a circumference 

 of 30-40 cm. (not millimetres as erroneously printed on p. 64). 

 The author finds reason to believe that these large stems, like their 

 still larger Pala30zoic allies, probably grew in thickness by the 

 development of secondary vascular tissue. 



One species — Lycopodites fahatus — is referred to the Club-Mosses, 

 and regarded as more nearly allied to the genus Selaginella than to 

 Lycopodium. The apparently heterophyllous character, on which this 

 conclusion is based, is not, however, a decisive argument, hetero- 

 phyllous species also occurring in the genus Lycopodium. 



The Ferns are, of course, abundantly represented ; the author 

 describes twenty species, and less cautious taxonomists would add 

 largely to their number. The Matoninese, a family of which the 

 author has treated at length elsewhere, are illustrated by some 

 splendid specimens of Matonidmm and Laccopteris. The evidence 

 appears fully to justify the author in his opinion that this group, 

 now so restricted, played an important part in the earlier Mesozoic 

 vegetation. 



Todites WilHamsoni is referred on good grounds to the Osmundace^e, 

 while species of the genus Coniopteris approach wonderfully closely, 

 in the characters both of the sterile and fertile pinnae, to the recent 

 Cyatheaceous genus Thyrsopteris, of which a single species survives 

 in the island of Juan Fernandez. 



The genus Bictyophylliim is placed, with Protorhipis, in the 

 Dipteridin^e, which the author regards as distinct from the typical 

 Polypodiaceee, while Khilcia and Enffordia represent the Schizaeaceee. 

 The presence of true Polypodiaceas is more doubtful, though several 

 genera, including Sagenopteris, often regarded as a Marsiliaceous 

 plant, are provisionally referred to this family. 



Among the numerous remains showing Cycadean affinities, two 

 genera, Williamsonia and Anoniozamites, are placed in the family 

 Bennettiteas, a remarkable group, with flowers far more complex 

 than those of the true Cycads, the characters of which have been 

 revealed to us by the investigations of Carruthers, Solras-Laubach, 

 Lignier, and others, on petrified specimens. Mr. Seward showed, in 

 his Wealden Catalogue, how close is the affinity between Williamsonia 

 and Bennettites, and, indeed, treated the former as a subgenus of 

 the latter ; in the present volume, however, the generic rank of 

 Williamsonia is again recognized. Mr. Seward has also previously 

 shown that the leaves of the old ' Zamia gigas ' really belonged to 

 the same plant as the Williamsonia flowers, and has thus completely 

 confirmed Williamson's original restoration of the plant. 



The genus Anomozamites, characterized by the almost entire or 

 imperfectly segmented leaves, is referred to Bennettitefe on the 

 evidence of specimens described by Nathorst from the RhEetic of 



