410 



SPHENOPHYLLUM. 



[CH. 



3. Sphenophyllum Thoni Mahr. Fig. 110, A. 



Another type of Sphenophyllum is illustrated by S. Thoni 

 Mahr as shown in fig. 110, J.. This species was first described 



B 



Fig. 110. A. Sphenophyllum Thoni, Mahr. (After Zeiller.) 



B. Sphenophyllum trichomatosum, Stur. From a specimen in the 

 Woodwardian Museum; from the Coal-Measures of Barnsley, 

 Yorks. A and B | nat. size. 



by Mahr^ from the Coal-Measures of Ilmenau, and has since 

 been figured by Zeiller and other authors. Each whorl consists 

 of six large obcuneiform leaves with the broad margin somewhat 

 irregularly fringed. The unusually good specimen of which 

 fig. 110, A, represents a single verticil was originally described 

 and figured by Zeiller in 1880"; it is now in the ficole des 

 Mines Museum, Paris. 



The leaf-forms illustrated by figs. 109 and 110 are some of 

 the more extreme types of Sphenophyllum leaves ; but these 

 are more or less connected by a series of intermediate forms. 



Mahr (68), PI. viii. 



Zeiller (80), p. 34, PI. clxi. fig. 9. 



