222 PALEOZOIC PALEONTOLOGY. 
HALYSITES CATENULARIA (Linn.). 
Plate XVII., Figs. 6-8. 
1767. Tubspora catenularva Linn., Syst. Nat., 12th edit., p. 1270. 
1851. Halysites catenularia E. & H., Monog. des. Polyp. Foss., p. 
asl. 
1852. Catenipora escharoides Hall, Pal. N. Y., vol. II., p. 12%, pl. 
35, figs. 1 a—c. 
1876. Halysites catenulata Rominger, Geol. Surv. Mich., vol. III., 
pt. UE., p..78, plagosaiigss 1, 2, 4. 
1899. | Halysites catenularia Lambe, Cont. Canadian Pal., vol. IV., 
pt. L., p. 68, pl. 3, figs. 1-1 b, 2-2 b. 
Description.—Corallum forming large masses, 10 to 40 cm. in 
diameter, made up of elongate, upright, subelliptical corallites, joined 
together by their edges in chain-like series, so as to form vertical, 
anastomosing lamine, inclosing interspaces of variable form and 
size. Between each pair of corallites is a small, vertical tubule, which 
is parallel with and of the same length as the corallites. In trans- 
verse section the corallites are about 2 mm. wide and 2.5 mm. long, 
subcircular or subelliptical in outline, with twelve septal spines. The 
tubules are quadrangular in outline, with their longer diameter trans- 
verse to the vertical lamina of corallites, and crossing the interspace 
may usually be detected one or more sections of the highly-convex 
tabule. In vertical section the corallites are crossed by numerous 
more or less concave tabule at varying distances apart. The tubules 
are crossed by highly-convex tabule, which are placed much closer 
together than those in the corallites. 
Remarks.—The form of chain coral which occurs in the coralline 
bed of the Decker Ferry formation is near the form considered as 
most typical of the species by Lambe, and is the form which most 
commonly occurs in the Niagaran faunas of America. 
