. Bulletins of American paleontology. Ordovician-Silurian Colonial Corals: Young and Ell\s 103 Table 22. —Biometric data for Pycnostylus sp. A from the east- central United States. CoD = corallite diameter. HT = wall thick- ness. LS = length of major septa. Ta5 = number of tabulae in 5 mm; = standard deviation, = coefficient of variation. parameters data CoD HT LS Ta5 mean mm mm 5% mm mm 4% minimum mm mm 0% 1 maximum mm mm 11% 4 no. of corallites studied 51 41 14 17 n=51 ,9. Corallite Diameter (
. Bulletins of American paleontology. Ordovician-Silurian Colonial Corals: Young and Ell\s 103 Table 22. —Biometric data for Pycnostylus sp. A from the east- central United States. CoD = corallite diameter. HT = wall thick- ness. LS = length of major septa. Ta5 = number of tabulae in 5 mm; = standard deviation, = coefficient of variation. parameters data CoD HT LS Ta5 mean mm mm 5% mm mm 4% minimum mm mm 0% 1 maximum mm mm 11% 4 no. of corallites studied 51 41 14 17 n=51 ,9. Corallite Diameter (mm) or wavy (PI. 21, figs. 19, 24). A colonial mode of growth is demonstrated by short to moderately long connec- tions between corallites at or near their bases, which may represent locations of increase (PI. 21, fig. 20). Connections between more mature parts of corallites are rare or absent. Corallite walls are thin, mm (Table 22); poor preservation prevents differentiation of the epi- theca and stereozone. Septa are lamellar; a single sep- tum can be amplexoid (PI. 21, figs. 23, 25) or can form a ridge showing relatively constant development (PI. 21, fig. 18). Major septa are moderately thick and short, with lengths up to 11% of the corallite radius (Table 22). In a transversely sectioned corallite, all major sep- ta are of about the same length (PI. 21, figs. 16, 23). Minor septa are recognizable where they rarely extend beyond the stereozone. They are short, up to about 3% of the corallite radius, and are thinner than major septa (PI. 21, fig. 17). Occurrence and abundance of septa generally increase with corallite diameter, with up to 28 major septa in the largest corallites. Septa are absent in all corallites with diameters less than 1 mm; their reduction in transverse sections of some larger indi- viduals (Text-fig. 33B) may be due to the amplexoid nature of septa. Tabulae are of moderate thickness, commonly con- cave, convex, or irregular; sometimes inco
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