234 



CIENIS. 



cells, whicli are 'well preserved, and readily examined under the 

 microscope after suitable treatment, are characterized by prominent 

 circular papillae agreeiag precisely with, those figured as sori hy 

 Eaciborski and other authors. It is not uncommon among recent 

 plants to find the surface cells of a leaf provided with conical 

 elevations or papillae ; the circular elevations on the epidermal cells 

 of Ctenis (Text-fig. 43, A p and B) are identical with those met 

 with in recent plants. The enlarged drawing (Text-fig. 43) demon- 

 strates the nature of these sorus-like projections as seen in the 

 Ctenis segments in the Manchester Museum. The three epidermal 



p 



Fig. 43. — Ctenis, sp. Epidermal cells of the specimen shown in Fig. 42,. 



highly magnified. 

 A. Cells in surface-view ; B. side-view of the epidermal cells, showing 

 the papilla;. 

 p = papiUEE ; s = stomata. 



cells shown in side-view in Text-fig. 43 B illustrates the nature of 

 the circular dots seen in surface-view in Fig. 43, p; the shaded 

 areas in the drawiag mark the position of depressions, which no- 

 doubt occur immediately above stomata (Fig. 43, s). 



In view of these facts, I prefer to retain Ctenis as a Cycadean 

 genus characterized by pianate fronds with linear segments- 

 traversed by parallel veins connected at intervals by lateral 

 anastomoses. 



