140 DICTYOPHYLLUM 
clusive as regards the claim of Dunker’s generic title to be 
retained. I expect that the discovery of more perfect examples 
of what Dunker designated Hausmannia may lead to the con- 
clusion that this genus represents a form of Dictyophyllum. A 
comparison of Schenk’s figures of Hausmannia dichotoma, Dunk., 
and Nathorst’s of Dictyophyllum Nilssoni, Brong.,! var. intermedium, 
in his ‘‘Flora of Sweden,” is very suggestive of the generic identity 
of the two species. 
Dictyophyllum Roemeri, Schenk. 
1871. Dictyophyllum Roemeri, Schenk, Paleontographica, vol. xix. p. 224, 
pl. xx. fie. 3: 
1892. ? Hausmannia Forchhammeri, Bartholni, Bot. Tids. Bot. For. 
Kjévenhavn, vol. xviii. Heft i. p. 26, pl. xi. figs. 4 and 4a. 
Type. Small sterile portion of a frond. In the University of 
Wiirzburg Collection. 
Schenk defines this species as follows :— 
“Folia... ? laciniz margine crenate, crene integra, nervi 
primarii validi, secundarii angulo recto egredientes, rami et 
ramuli in rete areas irregulariter polygonas formantes conjuncti.’’ 
In the fragments from the Sussex Wealden the sori are fairly 
clearly shown. 
Habit of the complete frond unknown; the lamina traversed by 
strong palmately-disposed veins which probably constitute the 
central axes of the leaf segments. 
The secondary veins form a reticulate structure, and in the larger 
meshes there are smaller reticulate branches; the sori scattered 
on the lower surface of the leaf; in some of these the sporangia 
appear to have a fairly regular arrangement in groups of four or 
more round a common centre. 
Schenk was the first to record this genus of the Dictyopteridee 
from Wealden rocks; the present species repeats such characters 
as are more distinctly shown in the much more perfect and larger 
fronds found in Rhetic and Jurassic strata. So far as the nature 
of the species is indicated by the few specimens from German 
and English beds, it appears to agree with Dictyophyllum 
tPl.iv. fig: 8: 
