114 Proceedings of the Royal Plmjsical Society. 



Size, including zone, 1*94 mm. ; diameter of disc, ll ram. 

 Rorizo7is. — Calciferous Sandstone Series and Carboniferous 

 Limestone Series. 



Locctlities,—1, 11 (?), 13, 17. 



TiULETES XVII. PL v., Figs. 11a, 17h, 



This form is closely related to the last, but the lower 

 surface is covered with a dense coating of stout bristle-like 

 hairs. The zone is occasionally solid, but sometimes divided 

 into a number of flat filaments with expanded heads, which 

 unite more or less among themselves. We were at first 

 inclined to regard this form as a variety of the last, and 

 although the differences between the two are difficult to 

 express in words, we believe them to be of such a nature as 

 to prohibit their being placed together. Specimens of this 

 form in groups of four also occur. 



Fig. 17b shows a portion of the zone, but the zone in the 

 form of its parts, even on the same specimen (like the zones 

 of the other specimens just described), varies much. 



Size, including zone, 2 mm. ; diameter of disc, 1*25 mm. 



Horizon. — Coal Measures. 



Localities. — 29, 32. 



TiiiLRTES XVIII. PL v.. Figs. 18a, Uh, 18c. 



This form is closely allied to the two last described, and 

 differs chiefly in the lower surface of the spore being 

 apparently quite smooth. 



The relationship of Trilctes XVI., XVII., and XVIII. to 

 each other, in the absence of any further data than that yet 

 afforded us, is very difficult to determine ; we have therefore 

 given figures of each. 



Size, including zone, 21 mm. to I'S mm. ; diameter of disc, 

 1-20 mm. 



Horizons. — Millstone Grit (?) and Coal Measures. 



Localities.— 24: (?), 35. 



Lagenicula, Kidston (New Group). 

 Macrospores of oval or circular outline (when compressed) 

 and provided with a neck-like projection (Fig. 20d), whic^ 



