110 Proceedings of the Royal Physical Society. 



Size. — 1'75 mm. to 1'6 mm. 



Horizons. — Millstone Grit and Coal Measures. 



Localities.— 22>, 25, 26, 27, 29, 33, 34, 35. 



Triletes X. PI. IV., Figs. 10a, 10&. 



Triradiate ridge occupying about one-half of the upper sur- 

 face. Apiculi on triradiate area small ; on other portions of 

 spine distant and small on typical forms, but some varieties 

 with larger spines occur in the Broomieknowe gathering, 

 which it is difficult to separate from the type. It is quite 

 possible, however, that two forms are included here ; but 

 awaiting further evidence, they are placed together. 



Size. — 1-82 mm. 



Horizon. — Coal Measures. 



Localities.— ?>0, 31, 32, 33, 34, 35. 



Triletes XI. PL lY., Figs. 11a, lib. 



Triradiate ridge occupying about one-half of the upper sur- 

 face, surrounded by an area bearing very small apiculi. Other 

 parts of surface of macrospore bear very stout, somewhat 

 distant and irregularly-disposed conical spines. The spines 

 are more distant and stronger than on Triletes VIII. In some 

 cases they bear comparatively few distant and irregularly- 

 distributed stout spines. 



Size. — 1*88 mm. to 1*70 mm. 



Horizon. — Coal Measures. 



Localities.— 2^, 31, 32, 33, 34. 



Triletes XII. PL IV., Figs. 12a, 12&, 12c, 12^, 12e. 



Spore smaU. Triradiate ridge occupies about one-half of the 

 upper surface of the spore, whose surrounding area is minutely 

 apiculate. The spines on the other portions of the spore are 

 small and sharp-pointed. The macrospores included here 

 vary considerably in size ; but they so pass into each other, 

 it has been found impossible to separate them. 



Size. — 1*36 mm. to 0*95 mm. 



Horizons. — Millstone Grit and Coal Measures. 



Localities. — 23, 24, 26, 35. 



