54 Annals of the South African Museum. 



shorter pinnules the lamina is traversed by several slightly diverging 

 veins which spring separately from the rachis, biat as the pinnules 

 become larger the veins tend to converge in the basal poi'tion 

 of the lamina, forming a midrib (pi. vii., fig. 8). In the apical portion 

 of the pinnae the divisions between the segments become shallower 

 and the apex consists of a bluntly terminated entire lamina. Epider- 

 nais composed of polygonal cells or — above the veins — of oblong 

 rectangular cells with very slightly undulating walls. Stomata not 

 very numerous, occurring on both the upper and lower epidermis, 

 probably slightly sunk, bordered by two or four cells which may be 

 subsidiary cells above the true guard-cells ; the pore of the stoma is 

 bounded by two crescent-shaped cuticular ridges which may belong 

 to the guard-cells. 



The specimens from the Stormberg beds are all sterile, and none 

 have been found showing the habit represented in Feistmantel's 

 figures of Australian examples. 



The most common form of pinna and pinnules is that represented 

 in fig. 1, pi. vii., in which the segments have no midrib but agree in 

 their venation with the genus Odontopteris. A few specimens occur 

 in which the pinnules are broadly linear and provided, at least in the 

 basal portion, with a midrib: these examples (pi. vii., figs. 7, 8) are, I 

 believe, specifically identical with those bearing shorter and broader 

 segments. Morris * referred the pinnjs with longer segments to 

 a variety — var. lancifolia, and by other authors this form has 

 been raised to specific rank. 



Geinitz f figures an example of a pinna with longer pinnules 

 from the Argentine which he names Thinnfeldia tenuinervis, and 

 Solms I refers a Chilian specimen of Ehgetic age to T. lancifolia. 

 Morris. 



Szajnochaj also adopts a distinctive name, T. lancifolia, for 

 Argentine Ehaetic specimens with linear pinnules. The occurrence 

 of intermediate forms of pinnules connecting those having almost 

 parallel veins with the longer ones, in which a midrib is well defined, 

 leads me to include both under one specific name. A similar course 

 is adopted by Feistmantel || in his Australian monograph. The 

 Ehsetic specimens described by Nathorst from Scania and placed in 

 the genus Ptilozamitcs exhibit a similar variation in the form and size 

 of the ultimate segments. 



The Queensland specimen figured by Carruthers is in the British 



* Morris (45), pi. vi., fig. 4. f Geinitz (76), pi. i., figs. 17, 18. 



X Solms-Laubach (99), pi. xiv., fig. 2. § Szajnocha (88). 



]' Feistmantel (90), pi. xxix. 



