XXXIX] OTOZAMITES 539 



walls and the stomata, apparently confined to the lower surface, 

 have guard-cells with hemispherical or spindle-shaped thickened 

 patches like those of some Zamites fronds. In one species, 0. 

 Feistmanteli Zig., Thomas found about 100 stomata in 1 sq. mm. 

 of lamina forming almost contiguous lines between the veins. In 

 the account of the genus Ptilophyllum reference is made to the 

 occurrence of pinnae with asymmetrical and auriculate bases, 

 and it is only by the comparison of a large number of specimens 

 that a distinction can be drawn between fronds that should be 

 assigned to Otozamites and forms of Ptilophyllum which exhibit 

 a well-marked tendency towards the Otozamites type of pinna 

 (cf. figs. 592, 593). The variation in the form of the apices of 

 pinnae and the relative position of the pinnae in different parts 

 of the same frond are features worthy of notice in the deter- 

 mination of species 1 . The different appearance presented by an 



A B 



FIG. 604. Otozamites Bechei. A specimen in the Bristol Museum seen from 

 below (A) and above (B). M. S. 



Otozamites frond as viewed from the upper and lower face is 

 illustrated in fig. 604. There are no recent Cycads in which the 

 segments have auriculate bases, but in this feature as in the 

 sinuous epidermal walls Otozamites agrees with some species of the 

 Fern Aneimia, e.g. A. rotundifolia Schrad. (fig. 223, Vol. n. p. 288). 



Otozamites Bechei Brongniart. 



There is considerable confusion in the nomenclature of this 

 species described by Brongniart 2 from Jurassic strata as Filicites 



1 Seward (95) A. PL i. figs. 1, 2. 



2 Brongniart (25) PL xix. fig. 4; Seward (00) B. p. 219; (04) B. p. 39. 



