XXXIX] 



ZAMITES 



533 



fronds usually occur as detached specimens and without any 

 associated flowers it is advisable, as Nathorst maintains, to retain 

 the non-committal genus Zamites. 



This type of frond is widely distributed in Jurassic strata. 

 The occurrence of many forms agreeing generally with the type- 

 specimen but differing from it in features that are not constant 



FIG. 599. Zamites gigas. (British Museum, V. 2723a; nat. size.) 



or of real morphological importance renders accurate specific 

 delimitation very difficult. Species that appear to be indistin- 

 guishable from Zamites gigas by any well-marked characters are, 

 Zamites Feneonis 1 Brongn., Z. Moreaui 2 Brongn., Z. Renevieri* 



1 Saporta (75) A. Pis. LXXXVH. xcn. 

 3 Ibid. PL xcm. 



2 Ibid. Pis. LXXXIV., LXXXV. 



