On Spores in the Carhoniferous Formation of Scotland. 113 



beautiful bright amber colour when examined by transmitted 

 lioht. 



Size.— lndwdimci zone, l-o7 mm. to 1'45 mm. Diameter 

 of disc, 1 mm. to 1*2 mm. 



Horizons. — Millstone Grit and Coal Measures. 



Localities. — 24, 26, 35, 36. 



Triletes XV. PI. IV., Figs. 15«, 15&, 15c, 15i, 15e, 15/ 



Triradiate ridge prominent, and extending over about four- 

 fifths of the upper surface of the spore. Other portions of 

 the disc indistinctly granulate (Fig. 15c). Zone of irregular 

 width, composed of flattened filaments, simple, clavate, or 

 ramified and more or less united at their expanded apices. 



The structure of the zonal appendages is shown at Figs. 

 IM, 15c, 15/ Fig. Ibd illustrates the fusion of the filaments 

 at their flattened and extended apices. 



The zone forms a circle immediately outside of the ex- 

 tremities of the arms of the triradiate ridge, and slightly 

 within the periphery of the (flattened) spore. 



Diameter of disc, 1'36 mm. Width of zone very variable, 

 attaining 0'51 mm. 



Horizon. — Millstone Grit. 



Localities. — 23, 24. , 



Triletes XVI. PL V, Figs. 16^^, 16&, 16c; PL IV., 

 Figs. 16cZ, 16c. 



Form of macrospore, sub-triangular. Triradiate ridge 

 extending to the base of the zonal appendages. Zone wide, 

 solid or more or less irregularly perforated. The lower surface 

 of the spore, especially towards its periphery, provided with 

 short, stiff, adpressed, outwardly directed hairs. 



Fig. 16c shows the structure of the zone. In many of the 

 specimens the openings are closed by a delicate membrane. 

 When viewed by transmitted light the appendages of the 

 macrospores of this division (III.) are of an amber colour. 



Specimens united in groups of four, which we believe to 

 be referable to this form, have been found associated with 

 the type. 



VOL. IX. H 



