PLATE 3 



All specimens photographed with transmitted light, unless otherwise indi- 

 cated. Color of filter, when used, also indicated. 



Triletes horridus (Zerndt) Schopf, Wilson, and Bentall (sensu Dijkstra) . p. 20 



Figure 



1. Slightly oblique compression. Maceration 914 slide 2, Tarter Coal, 

 Mercer County, Illinois. Reflected light, same scale as figure 12, (x40). 



Triletes crassiaculeatus (Zerndt) Schopf, Wilson, and Bentall p. 21 



2. Lateral compression. Lips partially torn away. Total length 2155 /*. 

 Maceration 943 slide 2, coal in the Bethel (Mooretown) Formation, 

 Hardin County, Kentucky. Reflected light, scale indicated below figure, 



(x20). 



3. Spines up to 288 ^ in length. Maceration 943 slide 9, coal in the Bethel 



(Mooretown) Formation, Hardin County, Kentucky. Red filter, scale 

 indicated at right of figure, (X150). 



Triletes rugosus (Loose) Schopf (sensu Dijkstra) p. 22 



4. Slightly oblique compression. Greatest dimension 645 /*. Spore coat 

 thin. Maceration 599B slide 5, Rock Island (No. 1) Coal, Fulton 

 County, Illinois. Same scale as figure 9, (X50). 



5. Slightly oblique proximo-distal compression. Diameter 895 p. Macera- 

 tion 825 slide 3, Colchester (No. 2) Coal, Schuyler County, Illinois. 

 Red filter, same scale as figure 9, (x50). 



6. Small example. Diameter 410^. Maceration 599B slide 7, Rock Island 



(No. 1) Coal, Fulton County, Illinois. Scale indicated below figure, 

 (X100). 



7. Lateral compression. Spore coat ornamented with small spines. Great- 

 est dimension 950 /x. Maceration 599B slide 5, Rock Island (No. 1) 

 Coal, Fulton County, Illinois. Red filter, same scale as figure 9, (x50). 



8. Lateral compression. Lips open. Arcuate ridges well defined. Total 

 length 955 /*. Maceration 825 slide 3, Colchester (No. 2) Coal, Schuyler 

 County, Illinois. Red filter, same scale as figure 9, (x50). 



9. Oblique compression. Lips open. Maceration 915 slide 3, Murphys- 

 boro (?) Coal, Williamson County, Illinois. Scale indicated below 

 figure, (x50). 



Triletes levis (Zerndt) Schopf, Wilson, and Bentall p. 24 



10. Lateral compression of small example with relatively thick arcuate 

 ridges and prominent trilete rays. Total length 445 fi. Maceration 600 

 slide 8, "LaSalle" Coal, Bureau County, Illinois. Scale indicated at left 

 of figure, (X80). 



11. Typical lateral compression. Total length 710 /i. Maceration 703 slide 

 1, "Woodbury" Coal, Cumberland County, Illinois. Reflected light, 

 same scale as figure 12, (x40). 



12. Lateral compression with inner membrane. Total length 1305 /x. Mac- 

 eration 136, Friendsville (?) Coal, Wabash County, Illinois. Red 

 filter, scale indicated at left of figure, (x40). 



13. Lateral compression with characteristic outline. Contact areas rela- 

 tively large. Apical prominence dense. Total length 1400 fx. Maceration 

 136, Friendsville (?) Coal, Wabash County, Illinois. Red filter, same 

 scale as figure 12, (x40). 



14. Lateral compression. Spore coat ornamented with small tubercles. Lips 

 split apart midway between their extremities and apex. Total length 

 1175^. Maceration 148, "Watson" Coal, Effingham County, Illinois. 

 Red filter, same scale as figure 12, (x40). 



[108 



