FOSSIL FORxMS 



273 



Charophyta 



Lagynophora, 3. genus from the Lower Eocene, can be ascribed to 

 this group, whilst Palaeonitella (fig. 176), from the Middle Devonian, 



••. V 



i.J.:^'--' 



Fig. 176. Charales. Palaeonitella Cranii {x 12^). (After Hirmer.) 



may belong here also although its affinities are not so clear. 

 Gyrogonites and Kosmogyra are names which have been given to 

 oogonial structures which closely resemble those of Chara, and 

 which are very abundant in the Lower Tertiary beds of England and 

 elsewhere. 



Phaeophyceae 



The principal fossil form ascribed to this group, Nematophyton, 

 has now been removed to a new group, the Nematophy tales (see 



P- 274). 



Rhodophyceae 



The Melobesiae are represented from the Cretaceous upwards 

 by species of Archaeolithothamnion, Dermatolithon, Lithothamnion, 

 Lithophyllum and Goniolithon, some of them only being distin- 

 guished with difficulty from living forms. The Corallinaceae are also 

 represented in the Cainozoic by extinct members of present living 

 genera. There are a large number of forms assigned to an extinct 

 family, the Solenoporaceae, which existed from the Ordovician up 

 to the Triassic, but neither their structure nor their systematic 

 position has been completely established. They formed nodules 



CSA 



18 



