76 ZAMITES. 



and it would seem that Brongniart's genus Zamites corresponds 

 most closely in general characters with these large Wealden fronds. 

 A brief review of some of the numerous definitions proposed 

 for Zamites may suffice to emphasize the generally accepted 

 characters, justifying at the same time Saporta's pertinent 

 remarks as to the vague sense in which the name has frequently 

 been applied. In 1828 Brongniart l proposed Zamites for a few 

 fossil fronds showing some points of difference from his other 

 genus Zamia; he mentions Z. Bechii, Brong., as an example 

 of the former, and describes the pinnse as: " Se recouvrant 

 mutuellement et passant sur le petiole commun ; nervures 

 divergentes arquees, souvent bifurquees." 



The name Zamia is afterwards given up as likely to prove 

 misleading as regards the relationship of fossil and recent 

 leaves, and Zamites is described as characterized by the possession 

 of entire pinna3, not truncate at the apex, and not decurrent, 

 but slightly constricted at the base. Brongniart includes Braun's 

 two genera Podozamites and Pterozamites as two subsections 

 of Zamites. Goppert 3 uses Zamites in a wide sense, and notes 

 the resemblance of some species to the genus Enceplialartos 

 among recent cycads. The similarity between various fossil 

 fronds and species of this living genus has not been sufficiently 

 recognized by most palseobotanical authors. Gb'ppert's definition 

 does not restrict Zamites to fronds with basal! y constricted 

 pinnae, but includes those with a swollen and auriculate 

 base. Pomel, 3 true to his unfortunate habit of founding new- 

 genera, proposes Crossozamia for certain species of Zamites, but 

 the name has not come into general use. Bornemann* describes 

 Zamites as comprising species with a greater or less resemblance 

 to the recent Zamias, and defines the genus as follows: "Frond 

 pinnate, leathery, pinna? approximate or distant, from ovate to 

 slender and linear in form, contracted at the base, entire or toothed 

 on the upper margin, blunt at the top. Veins of uniform size, 

 clearly seen on both sides of the pinna?, dichotoraous. Epidermal 

 cells having the same structure as in recent Zamias." Schenk 5 



1 Prodrome, p. 94. 



2 (1), P- 122. 



3 Pomel, p. 342. 



4 Bornemann, p. 54. 



6 (A. 1), Fl. foss. Grenz. Keup. Lias, p. 158. 



