GENUS DENSO-SPORITES 



33 



mal-distal portions of the spore coat are 

 estimated to be 2 microns thick; the equa- 

 torial portion ranges from 8.4 to 10.5 mi- 

 crons in thickness and comprises about 42 

 percent of the spore coat. 



Holotype. — Maceration 625-A Slide 1, 

 Willis coal bed, Gallatin County, Illinois. 



Discussion. — Figure 4, plate 6 illustrates 

 an oval outline as contrasted with the some- 

 what triangular outline of figure 5. Figure 

 4 illustrates the ornamentation of the proxi- 

 mal-distal portion of the spore which ap- 

 pears reticulate, and figure 5 illustrates the 

 vermiculate type of ornamentation. This 

 feature is entirely dependent upon the 

 focusing of the microscope. 



Denso-sporites reynoldsburgensis sp. 

 nov. 



Plate 6, figures 9-11 



Description. — Spores are radial, trilete 

 and roundly triangular as viewed in trans- 

 verse plane. The tetrad, plate 6, figure 9, 

 shows the spore to be subtriangular at right 

 angles to the transverse plane. The holo- 

 type (figure 10) measures 39.9 X 44.6 mi- 

 crons, and the known size range is from 36 

 to 47 microns. The proximal and distal 

 surfaces are slightly granular as viewed 

 under high dry magnification. With oil 

 immersion this portion of the spore coat is 

 either minutely granulose or punctate, 

 probably granulose. The juncture of this 

 portion of the spore coat with the equa- 

 torial portion is marked by ridge or fold 

 which completely surrounds the center area. 

 Due to compression, a portion of the 

 equatorial area overlaps on the distal side 

 of the central area. The thicker equatorial 

 portion of the spore coat is essentially opaque 

 with a few minor pits or punctations, and 

 minor folding of this area of the spore coat 

 is shown on plate 6, figures 10-11. This 

 species is definitely derived from tetrahedral 

 tetrads and the tetrad mark may be weakly 

 or strongly preserved on isolated specimens 

 as shown in figures 10-11, plate 6. The 

 rays do not extend into the equatorial por- 

 tion of the spore coat. The rays of the 

 holotype vary in length from 10.5 to 12.6 

 microns in length. The proximal-distal 



portion of the spore coat is less than 2 mi- 

 crons thick and the equatorial portion 

 averages 8.4 microns in thickness. A direct 

 transverse measure of the holotype reveals 

 that more than 39 percent of the spore is 

 the equatorial portion of the spore coat. 



Holotype. — Maceration 618 Slide 21, 

 Reynoldsburg coal bed, Johnson County, 

 Illinois. 



Discussion. — This species is similar to 

 but certainly not conspeciflc with D. annula- 

 tus (Loose) S. W. and B., 1944. 



Denso-sporites ruhus sp. nov. 



Plate 6, figure 6 



Description. — Spores are radial, trilete 

 (?), oval in transverse outline and with 

 occasional minor folds of the spore coat. 

 The holotype measures 42 X 52.5 microns, 

 and the known size range is from 42 to 53 

 microns. The proximal and distal portions 

 of the spore coat are punctate. The thicker 

 equatorial portion of the spore coat is some- 

 what irregularly thickened and the margin 

 of the spore coat is rough in appearance. 

 The trilete mark is indistinct to absent on 

 most specimens. The proximal and distal 

 portions of the spore coat are thin, not 

 more than from 1.75 to 2 microns thick. 

 The equatorial portion of the spore coat 

 varies in thickness from 8.4 to 10.5 microns. 



Holotype.— Maceration 587 Slide 13 

 Battery Rock coal bed, Hardin County 

 Illinois. 



Discussion. — This species is somewhat 

 similar to fig. 1 (Pagent, 1936) but prob- 

 ably not conspeciflc with it. D. ruhus sp. 

 nov. is characterized by its rather coarse 

 ornamentation. 



Denso-sporites sphaerotriangularis 

 sp. nov. 



Plate 6, figure 7 



Description. — Spores are radial, trilete 

 and roundly triangular in outline and lack- 

 ing folds, except at the inner margin of the 

 thick wall. At this point minor folds may 

 be distinguished. The holotype measures 

 48.3 X 50.4 microns, and the known size 

 range is from 46 to 59 microns. The proxi- 



