Miscellaneous. 



443 



the method of M. Brongniart, re-uniting however the two genera Za- 

 mia and Zamites into one genus, and adding the genus Zamiostrobus 

 (Endlich.) to designate their fructifications. 



Amongst the Cycadece hitherto known, and which M. Gceppert di- 

 vides into the four following sections, Cycadites, Zamites (comprising 

 the Zamiostrobus), PteropTiyllum and Nilsonia, the following species 

 have been discovered by the author : — 



Zamiostrobus (fruit) ovatus. 



crassus. 



Sussexiensis. 



Pterophyllum Oeynhausianum 



%). . 



Carnallianum (av. fig.). 



propinquum (av. fig.). 



gonorrbachis (av. fig.). 



Preslianum. 



taxinum. 



Pterophyllum Braunianum. 



Dunkerianum. 



Munsteri. 



(av. inconstans. 



difForme. 



lunulavifolium. 



Nilsonia compta. 



Bergeri. 



acuminata. 



Kirchneriana. 



The result of the enumeration made by the author is, that the 

 total number of the different species of fossil Cycadece known up to 

 the present time and designated by a specific name amounts to 78, 

 amongst which are 9 stems or stipes, 65 fronds and 4 fructifications. 

 The genera which compose this total are in the following propor- 

 tions : — 



The species are thus distributed in the diflferent formations : — 

 4 



Carboniferous formation 



Red Sandstone 1 



Gres bigarre 2 



Keuper 2 



Lias 19 



Oolite 29 



Jura 5 



Weald Clay 5 



Greensand 3 



Chalk 2 



Lignite 3 



Unknown deposit 3 



Making a large allowance for the inevitable reproductions of the 

 same species under new names, as well as for the probability that 

 many fronds and stipes, described as diflferent species, are only in 

 fact the integrant parts of the same individual, it is not less true that 

 on comparing the species of the fossil with those of the existing Cy- 

 cadea;, the total number of which is generally estimated at 38, the 

 numerical advantage will infallibly belong to the first, so that their 

 number may always be placed at double that of the recent Cycadea ; 

 inasmuch as the influence of the causes which would tend to reduce 



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