Miscellaneous. 



443 



the metliod of M. Brongniart, rc-uniting however the two genera 2^a- 

 mitt and Zamiffs into one genus, iind adding the genus Zumiostrohus 

 (Endlich.) to designate their frurtitication?. 



Amongst the Cymdcic hitherto known, and which M. Goc])pcrt di- 

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

 the Zmniastrobus), Ptcrophyllum and Nilsonia, the following species 

 have been discovered by the author : — 



Zamiostrobus (fruit) ovatus. 



crassus. 



Susscxiensis. 



rterophyllum Oeynhausianum (av. 



Cavnallianum (av. %.)• 



propinquuni (av. fig.). 



gonorrliacliis (av. fig.). 



Preslianum. 



taxinum. 



Ptcrophyllum Brauniainnn. 



DunkerianuHi. 



Muusteri. 



inconstans. 



diffbrme. 



lunularifolium. 



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 different formations : — • 



Carboniferous formation ... 4 



Red Sandstone 1 



Gres bigarre 2 



Keuper 2 



Lias I'J 



Oolite 29 



Jura 5 



Weald Clay r> 



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 different 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- 

 cadece, 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 Cycadece ; 

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



2 H 2 



