CLA.DOPHLEBIS. IBS' 



Before referring to other authors whose determinations are 

 mentioned in the above synonymy, it may he a convenience to 

 concisely summarize the conclusions to which an examination of 

 the East Yorkshire Cladophlehu fronds has led me. 



In the first place it seems almost certain that Pecopteris undans 

 as figured by Lindley & Hutton and others is, as Nathorst suggested,, 

 the fertile frond of Cladophlehis denticulata. Further reference is 

 made to this point elsewhere. The comparison of such specimens 

 as that figured by Lindley & Hutton as Pecopteris insignis, the 

 example represented in PL XIV. Fig. 1 (39,236), and many others, 

 with specimens like that shown in PI. XIV. Fig. 3, and as figured 

 by authors under such names as Neuropteris or Pecopteris ligata, 

 P. whithiensis, etc., in which the pinnules are smaller, has con- 

 vinced me of the identity of the fronds possessing larger and smaller- 

 ultimate segments. The prominence or almost complete absence of 

 denticulations on the margin of the pinnules are characters of slight 

 importance. In some cases, as an examination of type-specimens 

 has shown, segments with a finely dentate border have been 

 erroneously represented in drawings as pinnules with an entire 

 margin. In one or two specimens in the National Collection and 

 other museums the pinnules appear to be entire, but in other 

 respects the fronds cannot be separated from those with dentate 

 pinnules. To lay stress on such a point as this would be to- 

 magnify a character of very small importance to the rank of 

 a specific difference ; my impression is that on a large frond 

 of the fern Cladophlehis denticulata, we might well find some 

 pinnules with entire and others with a denticulate border. 

 Brongniart's species Pecopteris PMllipsii, as already suggested, is 

 probably a somewhat imperfect example of C. denticulata. 



There are certain species of fronds of the Cladophlehis tj-pe 

 figured by several authors from Jurassic horizons which present 

 a close agreement with C. denticulata, but which cannot with 

 safety be included in a list of synonyms. In Schenk's admirable- 

 work on the flora of the strata between the Keuper and the Lias 

 of Franconia a frond is figured as Asplenites Roesserti (Presl) ; the 

 drawing of this species in Schenk's pi. x. fig. 1 ^ agrees very 

 closely -with specimen No. 39,238 in the British Museum Collection, 

 and still more closely with a specimen in the Leckenby Collection 



' Schenk (67). 



