662 PROFESSOR A. C. SEWARD ON 



in its greater breadth, with such specimens as those seen in figs. 9 and 11. The larger 

 example shown in photo. 7, PL VI., bears a close resemblance to the genus Nathorstia, 

 the fructification of which has been recently described by Nathorst,* but I have no 

 doubt as to its generic identity with the smaller forms. 



It is not always easy to distinguish between Laccopteris and Nathorstia ; the form 

 of the pinnules is the same but the sori are distinct, those of the latter genus having 

 Marattiaceous affinities, while Laccopteris appears to be allied to Matonia. Dr 

 Nathorst, whose opinion I sought as to the nature of the fossil shown in photo. 7, 

 examined specimens from the same locality in his own collection and expressed the view 

 that the resemblance to Nathorstia does mean near relationship. 



Specimens undoubtedly identical with the Culgower plant are recorded from the 

 Wealden of Belgium, Germany, and England. The Jurassic species L. polypodioides 

 Brongn. and L. Woodivardi (Leek. ) f differ but little from the Sutherland fern. 



Text- Fig. 4.— Laccopteris Dunkeri Schenk. Venation of a piece of sterile pinnule ( x 8). (Gunn collection.) 



Saporta's specimens from the Bathonian of France described as Microdictyon 

 Woodwardi\ and Eaciborski's fossils § from the Lias of Poland described under the 

 same name afford examples of this widely spread Mesozoic generic type. The specimens 

 figured by Debey and Ettingshausen from the Lower Cretaceous of Aachen as 

 Carolopteris aquensis || bear a close resemblance to the Scotch species, and examples 

 of Laccopteris figured by Bartholin as Microdictyon sp.t from Bornholm are very 

 similar to the specimen represented in photo. 7, PI. VI. 



Matonidium, Schenk. 



Matonidium Goepperti (Ettingshausen). (PI. II. figs. 25, 26.) 



1846. Pecopteris Althausii, Dunker, Wealdenbilclung, p. 5, pi. ii. fig. 2. 



1852. Atethopteris Goepperti, Ettingshausen, Abh. Jc.-k. geoi. Reichs., Bd. i., Abth. iii., No. 2, p. 16, pi. v. 



1871. Matonidium Goepperti, Schenk, Palxoni., Bd. xix. p. 219, pis. xxvii., xxviii. 



I have retained the specific name instituted by Ettingshausen as being better 

 known than the older name under which Dunker first described the Wealden specimens 



* Nathorst (08). t Seward (00), pis. xii. xiii. ; text-fig. 11a. 



% Saporta (73), pi. xxx. § Raciborski (94), pi. xiii. figs. 10-14. 



|| Debey and Ettingshausen (50), pi. iii. figs. 20-27. H Bartholin (92), pi. x. fig. 2. 



