300 
Family, Rhinidictyonidae Ulrich. 
Genotype: Rhinidictya nicholsoni Ulrich. Stictopora (part) Hall, Pal. 
New York, 1, 1847, p. 73. Ulrich. Geol. Sury. Illinois, 8, 1890, p. 388. 
Rhinidictya Ulrich, Jour. Cincinnati Soc. Nat. Hist., 5, 1882, p. 152. Hall 
and Simpson, Pal. New York, 6, 1887, p. 20. Miller, N. A. Geol. Pal., 1889, p. 
320. Ulrich, Geol. Minnesota, 3, 1893, p. 124. Procta, Syst. Sil. Centre 
Boheme, § pt. 1, 1894, p. 15. Ulrich, Zittel’s Textb. Pal. (Engl. ed.), 1896, p. 
279. Simpson, 14th Ann. Rept. State Geol. New York for 1894, 1897, p. 
605. Nickles and Bassler, Bull. U. S. Geol. Surv., 173, 1900, p. 48. Grabau 
and Shimer, N. A. Index Fossils, 1, 1907, p. 158. Cumings, 32d Ann. Rept. 
Dept. Geol. Nat. Res. Indiana, 1908, p. 755. Bassler, Bull. U. S. Nat. Mus., 
77, 1911, pp. 131, 132; Zittel-Eastman Textb. Pal., 1913, p. 345. 
Zoarium bifoliate, continuous or jointed, consisting of compressed 
branches or leaf-like expansions: occasionally trifoliate; zooecia subgradu- 
ate, arranged longitudinally ; orifices and apertures elliptical or subcireular, 
sometimes a little truncated posteriorly ; median tubuli between the median 
laminae and between the longitudinal rows of zooecia ; mesopores wanting, 
but vesicular tissue often developed; inferior and superior hemiseptum 
sometimes present. The family has been redefined to include the new genus 
Hemidictya which has both inferior and superior hemiseptum. 
Genus Rhinidictya Ulrich. Genotype: Rhinidictya nicholsoni Ulrich. 
Stictopora (part) Hall, Pal. New York, 1, 1847, p. 73. Ulrich, Geol. Sury. 
Illinois, 8, 1890, p. 388. 
Rhinidictya Ulrich, Jour. Cincinnati Soc. Nat. Hist., 5, 1882, p. 152. Hall 
and Simpson, Pal. New York, 6, 1887, p. 20. Miller, N. A. Geol. Pal., 1889, 
p. 320. Ulrich, Geol. Minnesota, 3, 1893, p. 124. proces Syst. Sil. Centre’ 
3cheme, 8, pt. 1, 1894, p. 15. Ulrich, Zittel’s Textb. Pal. (Engl. ed.), 1896, 
p. 279. Simpson, 14th Ann. Rept. State Geol. New York for 1894, 1897, p. 
605. Nickles and Bassler, Bull. a S. Geol. Surv., 173, 1900, p. 48. Grabau 
and Shimer, N. A. Index Fossils, 1, 1907, p. 158. Cumings, 32d Ann. Rept. 
ahi Geol. Nat. oo Indiana, tan p. 755. Bassler, Bull. U. S. Nat. Mus., 
, 1911, pp. 131, 132; Zittel-Eastman Textb. Pal., 1913, p. 345. 
“Zaria compos et of narrow, compressed, dichotomously divided branches, 
with the margins sharp, straight and essentially parallel; attached to for- 
eign bodies by a continuous expanded base. Zooecial apertures subcireular 
or elliptical, arranged alternately in longitudinal series between slightly 
elevated, straight or flexuous ridges, Carrying a crowded row of small, blunt 
spines. Space immediately surrounding apertures sloping up to summits 
of ridges.” (Ulrich.) 
Rhinidictya tabulata n. sp. Plate XII, Figs. 5-6. Zoarium consists of 
bifoliated branching form, the branches rising from the margins; the type . 
specimen is 8 mm. wide, .8 to 1.7 mm. in thickness midway between the 
margins. The surface is even with an occasional subsolid area, formed by 
the thickening of the zooecial intersperspaces of mature specimens. The 
margins are thin, celluliferous, approximately parallel, except near the 
bifurcations. 
