262 SIGILLARIEAE. 



rinds, distinctly marked cicatrices and the structure above described, are 

 phanerogamous gymnospermous plants near modern Cycads,' we can 

 scarcely think his statement justified, when we consider that we do not 

 even know whether the specimen on which he founds this conclusion 

 really belongs to Sigillariae. But since he acknowledges, though not 

 without reserve, the correctness of Zeiller's observations, he arrives ulti- 

 mately at the following conclusion : ' The Sigillariae, an essentially transi- 

 tional group of plants, would therefore separate into Leiodermarieae or 

 phanerogamous Sigillariae with smooth rind near Cycadeae, and into 

 Rhytidolepis or cryptogamous Sigillariae with fluted rind allied to Isoetes.' 

 But this sentence is simply a petitio principii, for it is not easy to see 

 why we should separate the ribbed Sigillariae from the others, so long 

 as there are no reasons which compel us to do so. And now that we are 

 acquainted with an archegoniate fructification in the one group, we must 

 with Williamson and Zeiller assume the existence of a similar fructification 

 in the other group till proof to the contrary is produced. No doubt the 

 question of transition groups may have to be considered here, but it must 

 first be shown that there were such groups. And so till Renault can prove 

 his view, I shall from the facts which lie before us hold fast on the whole to 

 the opinion that the Sigillariae were of the nature of Archegoniatac. 



