Yol. 6S.'] THE MIDLAND AND SOTJTH-EASTBEN COAL MEAStTRES. 315 



Radial sector with five simple, backwardly-directed rami. 

 Median divided low down, with two principal branches, and ending 

 on the inner margin in five rami. 



Cubitus stout, widely spaced, divided into two principal branches, 

 the foremost with two rami and the hinder ending in four. 



Genotype : Pteronidia. Characters as above. 



iSi^ecies, plicatula. Characters. — Wings triangular in outline, 

 with subacute tip. Characterized by a strong plication. 



Eadius as long as the wing, radial sector dividing into five simple 

 rami. Median with two principal branches and five marginal rami. 

 Cubitus wide-spaced ; two principal branches, the inner one being 

 doubly furcate. 



Horizon and locality. — Some 30 to 40 feet below the 

 Top Hard Coal, Middle Coal Measures, Shipley Clay-pit, Hkeston 

 (Derbyshire). 



Cetptovenia motseyi, gen. et sp. nov. (PI. XXXII, figs. 4-6.) 



The inner two-thirds of a left wing, contained in a portion of 

 a brown, earthy ironstone-nodule. The length of the portion 

 preserved is 16 millimetres, and the maximum width does not 

 exceed 8 mm. 



The costal vein is stout, and raised above the general level of the 

 wdng in the outer third of its length. It forms a strong sweeping 

 curve backwards, so that the apex of the wing is brought near the 

 inner margin. 



The subcostal vein is a weaker vein than the costal, runs 

 parallel and very close to the latter, and dies out where the 

 backward sweep of the costal begins. 



The radius is a powerful undivided vein, which gives off the 

 radial sector below the middle of the wing and curves first inwards 

 and then outwards, in the latter part of its course becoming parallel 

 to the subcostal, but three times as widely separated from it as the 

 latter is from the costal. It reaches the margin in the middle of 

 the outer half of the wing-tip. 



The radial sector, like the radius, first curves inwards and then 

 outwards, and diverges somewhat widely from the radius. It 

 gives off two forwardly directed branches, the outer of which forks 

 twice, the inner branch remaining simple. The outermost ramns 

 of the radial sector runs out into the extreme tip of the wing, the 

 other four rami covering the whole of the inner half of the tip. 

 The outer half of the whole wing- tip is thus occupied by the curved 

 costal and the radius, and the inner half by the inner four rami 

 of the radial sector. 



The median vein is of comparatively simple structure, forking low 

 down below the middle of the wing into two nearly equal branches. 

 The outer branch remains undivided, and passes outwards and back- 

 wards in a gentle curve to the inner margin. The inner branch 

 divides twice, first at a point a little below the middle of the wing, 

 and again before reaching the margin. The median vein therefore 



