546 CYCADOPHYTAN FRONDS [CH. 



DICTYOZAMITES. Oldham. 



This generic name was instituted^ for pinnate fronds from the 

 Rajmahal series of India, assigned by Feistmantel to a Lower 

 Jurassic horizon, but probably nearer in age to the Middle Jurassic 

 series. Morris, joint author with Oldham of the Memoir on the 

 Rajmahal plants, adopted the name Dictyopteris. Dictyozamites 

 agrees very closely with Otozamites but is readily distinguished 

 by the anastomosing veins (fig. 609), while the absence of a midrib 

 differentiates it from the Palaeozoic genus Dictyopteris. The 

 genus is recorded also from Jurassic strata in England, Bomholm, 

 Japan^, Korea^, and from a locahty 60 nautical miles N.W. of 

 Cape Horn in Tierra del Fuego* : the specimens from these localities 

 differ only in unimportant details from the Indian type. Dictyo- 

 zamites is confined to Jurassic floras and appears to be especially 

 characteristic of Middle Jurassic floras. In India^ fronds occur 

 in close association with stems of the Bucklandia type and, although 

 there is no proof of any connexion with stems or flowers, it is 

 probable that the fronds of this generic type were borne on stems 

 similar to those of Bucklandia and that the flowers were constructed 

 on the Williamsonia plan. 



Dictyozamites fakatus (Morris). 



Morris^ described this Rajmahal species under the names 

 Dictyopteris falcata and D. falcata var. obtusa ; the specimens were 

 included by Feistmantel under the designation Dictyozamites 

 indicus, the original term falcata being discarded without adequate 

 reason. An examination of several of the figured fronds enables 

 me to confirm the accuracy of the pubhshed drawings and to 

 extend the description in a few particulars. Fronds piimate 

 of the habit of Otozamites; pinnae comparatively thick, broadly 

 linear, alternate, varying considerably in size and in the form 

 of the apex which may be obtuse or acute. The pinnae are 

 attached by the middle part of the lamina only ; the upper edge 

 of the base is slightly rounded or auriculate; the lower angle 



1 Oldham and Morris (63) B. p. 37. 2 Seward (03). 



2 Yabe (05) B. PI. u. figs. 2—7. 



' HaUe (12); (13) p. 9, PI. v. figs. 29—33. 6 Bancroft (13). 



« Oldham and Morris (63) B. PL xxiv. figs. 1,2; Feistmantel (76^=) Pis. iv. — ^vi. j 

 (77) PI. n. 



