﻿Vol. 64.] 



POSSIL PLINTS PROM SOUTH AFRICA. 



91 



forked secondary veins ; or as possessing several simple or dicho- 

 tomously branched veins, which are direct branches from the axis 

 of the pinna or rachis ; or, finally, as exhibiting a combination of 

 these types, the veins being in part branches of one or more larger 

 veins and in part direct offshoots of the pinna-axis. Text- 

 figures 3A-3D (belo\^) illustrate these different forms of venation 

 in the pinnules of Thinnfeldia. 



In some of the larger specimens of the genus another character 

 is exhibited : namely, the apparent dichotomy of the main axis of 



Fig. 3. — Pinnules of Thinnfeldia odontopteroides {A-D) and 

 Ptilozamites {E) showing venation. 



[A-D are South African specimens ; E is after Nathorst.] 



the frond ; this is well shown in Feistmantel's figures of Th. odonto- 

 pteroides ^ and in South African examples of the same species. 



To turn to Ctenopteris and Ptilozamites : the former name, 

 originally suggested by Brongniart for the Liassic plant Ct. cijcadea,^ 

 is used in preference to the term Ctenozamites, proposed by Prof. 

 Nathorst,^ on the ground of priority. These generic names are applied 



^ Feistmantel (00) pis. xxiii-xxv, «tc. 

 2 Saporta (73) pp. 351, 352. 



Nathorst (78) p. 122. 



