Mr. J. Morris on recent and fossil Cycudecc. 11 'J 



P. filiciformis, Zamites fiUciformis, Presl, /. c. pt, 7. and 8. j). 198. 



Fi/icites dubius, Sternb., pt. 4. p. 23. t. 47. f. 1. 

 P. obtusum, Odontopteris obtusa, Brong. Hist. Veg. Foss., t. 78. f. 4. 

 P. latifoliiis, 0. latifoUus, Sternb., pt. .5. and G. p. 79. Taidopteris 



latifolius, Brong., t. 82. f. 6. 



Apex acute. 

 P. acuminatum, Zamites, Presl, /. c. p. 198. t. 43. f. 2. Keuper, Bam- 

 berg. 



P. Brongniarti, Cycadites, Mantell, Geol. S.E. England, p. 238. 

 Wealden, Sussex. 



P. heterophyllus, Zamites, Presl, p. 199. t. 43. f. 4, 5. Keuper, Bam- 

 berg. 



P. tenuicauUs, Cycadites, Phillips, pt. 1. t. 7. f. 19. Gr. Ool., Gris- 

 thorpe Bay. 



P. difformis, Zamites, Presl, /. c. pt. 7, 8, p. 198. Aspleniopteris dif- 

 formis, Sternb., pt. 4. p. 21 ; pt. 2. t. 24. f. 1. Bohemia. 



The following species I have not seen : — 

 P. longifolium, Brong. Prod., p. 95. Algacites filicoides, Schloth. 



Nachtr., p. 46. t. 4. f. 2. Lias. 

 P. Meriani, Brong. Prod., p. 95. Lias. 

 P. Williamsonis, Brong. Prod., p. 95. Inf. Ool., Whitby. 

 P. enerve, Brong. Prod., p. 95. Variegated marl. 



NiLssoNiA, Brong. 



Fronds pinnate ; pinnae approximate, oblong, more or less elongate, 

 apex rotundate, adhering by their whole base ; veins unequal, pa- 

 rallel. 

 N. brevis, Brong., Ann. des Sc. Nat. 4. p. 218. t. 12. f. 4 ; Hist. Let. 



Suae. Hoer, Sweden. 

 A'', elongata, Brong., I. c. 1. 12. f. 3. Zamites, Presl, /. c. p. 198. Hoer, 



Sweden. 

 N. proxima, Cycadites Nilssonii, Sternb., pt. 1 — 4. t. 47. f. 1. 



The above is an outline of some of the characters in the recent 

 and fossil Cycadeae, the geological position of which is equally in- 

 teresting with their recent affinities. A few species are found in the 

 carboniferous beds of Bohemia and in the new red sandstone of Ger- 

 many, and some have also been met with in the cretaceous series of 

 Denmark and Sweden ; but their great development appears to have 

 been during the Jurassic period, thirty species occurring in the 

 oolitic formation of England, and three in that of India. 'I'hus they 

 seem to have formed the characteristic vegetation of that age, inter- 

 mediate between the abundant Cryptogamic tribes of the carboni- 

 ferous aera and the dicotyledonous flora of the tertiary series. 



The great number of fossil species supposed to belong to this fa- 



