FROM THE HTJTTON COLLECTION. 87 



161. (Neuropteroid frond, Lebour, 111. Foss. Pits. pi. 15). Type. 



Small portion of a terminal pinna. 



Loc. — Shale above the Bensham Seam, Jarrow. (H. C. — ). 



162,—Pecopteris laciniata, L. et H. Type specimen, F. F., pi. 122. 

 Fragments of two or three very much compressed pinnag. It 

 is, as conjectured by Hutton, only a variety of P. muricata. 



Loc. — Shale above the Bensham Seam, Jarrow. (H. C. 283). 



163. (Lebour, 111. Foss. Tits., pi. 29). Type. 



A terminal pinna, with pinnules similar to the preceding, 

 appears to be identical with Brongniavt's Sphen. acutifolia. 



Loc. — Shale above the Bensham Seam, Jarrow. (H. C. 629). 



Remarks. — Like all ferns common and widely distributed this 

 has received an abundant supply of names, even from the best 

 authorities, but if the original specimens of all the figures quoted 

 above could be brought together for comparison, there are very 

 few who would propose to divide such an assemblage into 

 species. It must be owned that no very large fragments or 

 perfect fronds have yet been found in this district, but fragments 

 large enough and well preserved have been seen to connect the 

 two most divergent forms, N. muricata, Schloth., and N. nervosa, 

 Brongt., and even in the small lax forms of N. muricata, no 

 specific character can be found by which they can be separated 

 from the more robust and closely-pinnulated variations. With 

 fossil ferns, as with recent ones, great allowances must be made 

 for the different localities and conditions and age, and the strong 

 tendency and power which some of the most widely distributed 

 plants have to produce variation. The list of synonyms given 

 above does not by any means include all the useless names 

 attached to this species. The sooner some effectual method is 

 found out and agreed upon to purge the nomenclature of fossil 

 plants from these burdensome lists the better will it be for 

 future investigators. Nothing but a careful Monograph on 

 Fossil Plants, worked out in the same self-denying and unflinch- 

 ing manner in which Thomas Davidson has worked out the 

 Fossil Brachiopoda, will be able to secure this boon. 



