230 DR. A. C. SEWARD : 
specimens in Lower Jurassic strata in the Island of Bornholm has enabled 
Halle to demonstrate a very close agreement with Dipteris in the structure 
and spore-output of the sporangia. 
To the Matonine it is customary to assign the fossil genus Laccopteris, a 
type agreeing in habit and in the structure of the sporangia with Matonia. 
The presence of an indusium has not been demonstrated, but in view of the 
detachable nature of the soral covering in Matonia, little weight can be given 
to negative evidence. In the pinnules of Laccopteris the veins are more 
fully anastomosed than in Matonia, but in this respect there is considerable 
variation. 
Fossil fronds agreeing still more closely with those of the recent genus 
are referred to Matonidium, and some of these cannot be generically distin- 
guished from Metonia pectinata. The discovery of rhizomes of a Wealden 
species of Matonidium in Belgium with the characteristic polyeyclie stelar 
structure afforded welcome confirmation of the close affinity of the fossil to 
the recent Ferns. The Belgian specimens will, it is hoped, soon be described 
in detail by Dr. Bommer. Some of the fronds of Matonidium from Jurassic 
and Wealden rocks in England and other countries differ from those of the 
recent species in the greater production of sori and in the larger number of 
sporangia in each sorus. 
Fossils from Rheetic beds in Franconia and Sweden described as species 
of the genera Andriania, Gutbiera, and Solenocarpus agree in habit with 
Matonia but ditfer in the form of the sort. 
Reference may also be made to certain fossil fronds described under the 
name Nathorstia: in habit as in venation and form of the pinnæ this genus 
is indistinguishable from Zaecopteris, but the examination by Nathorst of 
fertile specimens from Cretaceous strata in Western Greenland and by Halle 
of material from Upper Jurassic, or Wealden, beds in Patagonia has failed 
to demonstrate the occurrence of annulate sporangia. The circular sori 
appear to consist of radially disposed synangia which the authors compare 
with the sori of the Marattiaceous genus Christensenia (= Kaulfussia), though 
in detail there are certain differences. Unfortunately specimens collected 
last year by Mr. Holttum and myself in Greenland, though supplying some 
new facts, did not throw any light on the structure of the sori. The avail- 
able evidence does not entitle us to assign Nathorstia to the Dipteris-Matonia 
alliance ; nor, on the other hand, am I convinced that the soral characters 
justify inclusion in the Marattiacew. It is noteworthy in this connexion 
that we found well-preserved, fertile Laccopteris fronds in the Cretaceous 
plant-beds of Greenland. 
Weichselia, a fern with large fronds and short linear pinnules with 
anastomosing veins which is characteristic of Wealden or Lower Cretaceous 
floras in several parts of Europe, probably represented in the Cretaceous flora 
of Egypt and recently discovered in Wealden beds in Peru, calls for a brief 
