Vol. 70.] FEOM THE EADSTOCK COAL MEASURES. 



125 



seen upon the principal veins in the Radstock wing. 31. monyi is 

 also a wider wing, with only one trace of elongated cellules along 



the proximal hinder margin, 

 and no areolae are present in 

 the cellules around ' Vein X.' 

 These differences are scarcely 

 generic, and I see no reason 

 why the wing should not be 

 classed as Meganeurid. 



It is possible, perhaps, to 

 regard the frontal tubercular 

 bar not as a modified alar area, 

 but as a highly-modified costa, 

 closely attached to the sub-costa 

 along its whole length. If such 

 a view be taken, the second 

 principal vein would be the 

 adius, and the media and the 

 ein-complex developed from it 

 ould alone be absent. 

 Such a view I had once taken, 

 but have abandoned in favour 

 of that already set forth. Con- 

 sidered as a Meganeurid wing, 

 the Radstock specimen is no 

 primitive structure, but a highly- 

 modified wing, in which a se- 

 condary development of spines 

 and tubercles is a strong fea- 

 ture. In the absence of the 

 hinder wing, it is not possible 

 to determine whether the mar- 

 ginal spines upon the inner 

 border served for interlocking 

 the two wings during flight, 

 but some such function appears 

 to be suggested by the evidence. 

 Even if it should be considered 

 that the difference which separ- 

 ated the Radstock specimen 

 from 3Leganeura monyi was of 

 generic rank, the fragmentary 

 character of the specimen, and 

 my consequent inability to de- 





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 o 



2 







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^ 



so 



^ 

 ^ 



termine all possible generic 

 characters, causes me to place 

 the specimen provisionally in 



the genus Meganeura, and as a new species — to which I attacli the 



name of radstock en sis. 



The specific characters are the presence of a tubercular and 



