Vol. 70.] FROM THE RADSTOCK COAL MEASURES. 123 



backward curve of the cubitus : as a result, the two veins are 

 somewhat widely separated proximally, and distally approach each 

 other closely. The anal is, in this wing, a powerful vein, and 

 certainly occupied more than half of the hinder wing-margin. 



The anal gives origin along the whole length of its hinder 

 margin to a series of branches, which arise at slightly increasing 

 intervals, being closest proximally and most widely separated 

 between the twelfth and thirteenth branches, beyond which the 

 interspaces narrow up to the origin of the fifteenth branch. These 

 branches, proximally, pass in straight, or slightly oblique, lines 

 backwards to the wing-margin. Farther out thev become curved, 

 the convexity being towards the wing-apex. The twelfth branch 

 is a strong and important vein, which sweeps in a powerful 

 double curve outwards and backwards to the wing-margin. It 

 corresponds in position to Brongniart's ' Vein X.' Beyond it are 

 the remains of three feebler veins, which bend in a simple curve to 

 the margin. The spaces between the branches are divided up into 

 a series of quadrangular areas or cellules, by a great series of 

 secondary rami arising at right angles to the branches. The 

 twelfth branch, which stands out by reason of its robust character 

 and sweeping curve, gives off, in its inner side, a series of rami 

 which divide and separate so widely that at first a double, and then, 

 near the wing-margin, a treble series of cellules are enclosed between 

 them. On its outer or distal side, it cuts off a series of five branches 

 arising from the hinder border of the main stem of the anal, the 

 enclosed quadrangular areas being increasingly elongated antero- 

 posteriorly up to the eighteenth branch, the course of which is not 

 interrupted by that of the twelfth. 



'Vein X' of Brongniart. — The cellules enclosed in the anal 

 area by this vein show a tendency to irregularity, both in size and 

 in form, much in excess of the irregularity noted in jSLeganeura 

 monyi, and those cellules which lie along the hinder wing-margin 

 are longer than wide. 



The integument in many of the quadrangular cellules is marked 

 by a slight central elevation, which, under high magnification, 

 presents the appearance of a circular thickened lip, with a central 

 depression or perf oration. These structures are marked by no 

 regularity of disposition, but are most numerous on each side 

 of the twelfth branch of the anal. The integument within the 

 cellules is, in some instances, obliquely wrinkled. The hinder wing- 

 margin is almost straight, well defined, and spinous along the whole 

 or a great part of its length. The spines are low, directed out- 

 wards, and in general character somewhat similar to those that occur 

 in the anterior margin of the wing. They are not so clearly shown, 

 however, and it is doubtful wmether they are truly marginal, or 

 whether the integument stretches a little beyond them : I incline 

 to the latter view. The wing-fragment appears to lie with the 

 ventral surface uppermost. It is, therefore, a proximal 

 fragment of a right wing. 



