GENERIC REFERENCE. 123 



neuropteroid bases are not very rare in-the lowest pinnules of Alethopteris 

 and Callipteridium. In recent works interpreting the fossil according to 

 the habit of recent ferns, a simple frond is not generally made an essen- 

 tial character of the genus Tmniopteris. So far, I believe, no one has de- 

 scribed the upper portion of the pinna of any of the pinnately divided 

 speeies now retained in the latter genus, the remains consisting generally 

 < f detached pinnules and fragments separated by reason of their decidu- 

 ous tendency. 



My reference of the Missouri species to Ta niopteris is provisional. The 

 fern is in its habit, and to some extent its nervation, evidently closely 

 related to Alethopteris. As remarked above, it should perhaps be in- 

 cluded in the same genus with Danasites (Aleth.) macrophylla (Newb.) 

 Lesq. ; but from the character of the rachis, midrib, form of pinnules 

 and the nervation, and from the observed development of the upper part 

 of some of the tseniopteroid forms in the older Mesozoic and Carbonif- 

 erous, I have been led to place it among the Taeniopterideae, and notwith- 

 standing the high degree of its superficial identity with them arattiaceous 

 forms comparable in their fructification to Danasa or Angiopteris, it seems 

 better, in default of all knowledge of the fruiting of our species, to refer 

 it to the genus Tmniopteris, the former resting-place of many of the Meso- 

 zoic species, rather than to the equivocal genus Dana ilex. It is certainly 

 ineligible to admission in the Dana ites of Goeppert and Stur. The name 

 Danasites, in the sense in which it is employed by Heer and Schimper, 

 should, if used at all, perhaps be applied to those species only of which 

 either the fruiting is known or the generic identity with other contem- 

 poraneous fruiting species is by other evidence satisfactorily proven, 

 leaving their apparent representatives from the Paleozoic, the fruiting of 

 which is not known, in the convenient and non-committal genus Taeniop- 

 teris, without presupposing any direct genetic relation to any particular 

 fruiting genus. 



Suggested genetic Relations. — The combination of alethopteroid and 

 tseniopteroid characters in the plant from the Lower Coal Measures of 

 Missouri more than strongly suggests a genetic relationship between the 

 pinnate tseniopterids (including the Paleozoic Danseites of the type A 

 macrophylla), and in probable sequence the Mesozoic tseniopteroid marat- 

 tiaceas, on the one hand, and the Lower Carboniferous alethopteroid 

 genera on the other; or, considering together with the alethopterids their 

 close natural allies, the neuropterids, we may suppose the relationship 

 to extend, as I shall try briefly to indicate, back to the megalopterid 

 stock, in which they may have had their origin. 



The genus Megalopteris, described from the Middle Devonian of Saint 

 Johns, New Brunswick, by Sir William Dawson as a subgenus of 



