CONIOPTEKIS. 101 



Type-specimens. Sphenopteris hymenophylloides, Brongn., in the 

 Paris Museum. [S. arguta, L. &H., Manchester Museum. 1 8. nephro- 

 carpa, Bunb., Leckenhy Coll., Cambridge. S. Murrayana, with 

 fertile pinnae of Tympanophora racemosa, figured by Leckenby, in the 

 Leckenby Coll., Cambridge. S. muscoides, Phill., York Museum.] 



Frond tripinnate ; pinna? linear acuminate, attached to the rachis 

 &t a wide angle ; the pinnules vary considerably in size and shape, 

 in some forms they have a few broad and rounded lobes and in 

 others the lamina is deeply dissected into narrow linear segments. 

 The fertile pinnules bear the son at the ends of the veins ; the 

 lamina is usually much reduced, and in extreme cases the fertile 

 segments agree closely with those of Thyrsopteris elegans, Kze., or 

 Dichonia Bertervana, Hook. The sori are partially enclosed in 

 a cup-shaped indusium ; the sporangia appear to have an oblique 

 annulus of the Cyatheaceous type. The two lowest pinnules of 

 a pinna are often characterized by their unusual shape, the lower 

 half of each pinnule consisting of long spreading and irregular 

 Aphlebia-\ike lobes (vide PI. XXI. Figs. 1-4). 2 



Venation and form of the frond of the Sphenopteris type. 



Brongniart's figure of the type-specimen of Sphenopteris hymeno- 

 phylloides agrees very closely with the example represented in 

 PI. XX. Fig. 1 of this Catalogue ; the only difference being that 

 Brongniart's specimen is a somewhat large form. Phillips' species 

 8. stipata is included by the French author as a synonym of 

 S. hymenophylloides. The following is the original diagnosis of 

 S. hymenophylloides : 



"8. foliis bipinnatis, tenuissimis, pinnis lineari - lanceolatis, 

 rachi alato ; pinnulis approximatis, ovatis, pinnatifidis, lobis ovatis 

 tridentalis, inferiori et exteriori (versus apiccm pinnarum) majori, 

 pinnatifido; nervulis tenuissimis." 



Brongniart compares S. hymenophylloides with the filmy ferns 

 Hymenophyllum and Trichomanes, but with his usual astuteness 

 he expresses the opinion that there is a more perfect analogy with 

 some of the recent Dicksonias, e.g. D. rubiginosa, D. dissecta, etc. 



Phillips' species, S. stipata, is represented in the first edition 

 of the Geology of Yorkshire by a very poor figure ; in the third 



1 Refigurecl, Seward (00), p. 6, fig. 1. 



3 Cf. certain Palaeozoic ferns some of which Potonie has referred to the 

 genus Alloiopteris : Potonie (99), p. 139. 



