178 THE DEVONIAN OF MISSOURI. 



Favosites helderbergiae Girty, 1895, 48th Ann. Rept. N. Y. State Mus. Nat. Hist., vol. 



II, pi. 302. 

 Favosites heldefbergiae Weller, 1903, Pal. N. J., vol. Ill, p. 270. 

 Favosites helderbergiae Shimer, 190.5, N. Y. State Mus., Bull. 80, p. 235. 

 Favosites helderbergiae Clarke, 1908, N. Y. State Mus., mem. 9, pt. 1, pp. 113, 218. 

 Favosites helderbergiae Clarke, 1909, N. Y. State Mus., mem. 9, pt. 2, p. 49. 

 Favosites helderbergiae Grabau and Shimer, 1909, N. Am. Index Foss., vol. I, p. 85, 



fig. 138. 

 Favosites helderbergiae Swartz, 1913, Md. Geol. Surv., L. Dev., p. 208, pi. XXII, fig. 1. 



Description — "Corallum consisting of large, lenticular, depressed convex or hemis- 

 pherical masses; base covered by a strongly wrinkled epitheca. Cell tubes polygonal; 

 their inner surface showing evidence of a few strong longitudinal striae. Septa frequent, 

 from ten to fifteen in the space of 10 mm. ; thickness equal to that of the cell walls. Mural 

 pores in one or two ranges, comparatively large, circular, with margins distinctly ele- 

 vated. Cell walls thin, but frequently much thickened near the surface by silicification, 

 and sometimes granulose or spinulose on the inner face. On some specimens the cells, 

 at the surface, are nearly equal, having a diameter of about 1.5 mm.; on other speci- 

 mens the diameter varies from .66 mm. to 1.5 mm. 



"On many specimens some of the cell tubes are larger and less angular than those 

 surrounding them, being a little more than 2 mm. in diameter. A single specimen 

 from Coeymans Handing has slightly larger tubes on one portion, while on all the other 

 parts the cells have the ordinary characters." — Hall, 1887. 



Dimensions — Figured specimens indicate variation in size of coralla. Range in 

 greatest internal diameter of corallites of the various specimens about 0.25 to 2.25 mm. ; 

 maximum range for any one specimen 0.7 to 2.25 mm. 



Remarks — The specimens represent coralla of various shapes. 



Hall figures a specimen of F. helderbergiae from New York "which differs from the 

 prevailing specimens in having numerous and somewhat regularly distributed larger 

 cells which are subcircular at their apertures." 1 This character prevails among the 

 Missouri specimens. 



The arrangement of the tabulae is accurately determinable only on portions of two 

 of the specimens. The disposition of the mural pores is accurately determinable, and 

 the septal spines are observable (to the unaided eye) on portions of all of the specimens. 

 Two of the specimens show epitheca. 



Favosites conicus Hall 



Plate 41, figures 2-7 



Favosites conica Hall, 1874, 26th Ann. Rept. N. Y. State Mus. Nat. Hist., p. 112. 

 Favosites conica Hall 1879, 32nd Ann. Rept. N. Y. State Mus. Nat. Hist., p. 146. 

 Favosites conicus Hall, 1883, Rept. State Geol. N. Y. for 1882, pi. Ill, figs. 4, 6-13 

 Favosites conicus Hall, 1887, Pal. N. Y., vol. VI, p. 9, pi. Ill, figs. 4, 6-13. 

 Favosites conicus Girty, 1895, 48th Ann. Rept. N. Y. State Mus. Nat. Hist., vol. II, p. 



302. 

 Favosites conicus Girty, 1899, U. S. Geol. Surv., 19th Ann. Rept., pt. Ill, p. 560. 

 Favosites conicus Swartz, 1913, Md. Geol. Surv., L. Dev., p. 212, pi. XXIII, figs. 5-7. 



Description — "Corallum forming conical- masses; flattened at the base, which is 

 covered by a strong epitheca, marked with concentric wrinkles and undulations and 

 radiating undulations formed by the cell tubes. Cells arising from the center of the base 

 and from an undefined central axis and quite abruptly curving to the surface, increasing 

 by interstitial additions; polygonal, from four to eight-sided; diameter at the surface 

 varying from 1.5 to 3.5 mm.; walls comparatively strong; interior with evidences of 

 numerous spinules or small nodes. Tabulae of about the same strength as the walls, 



'Pal. N. Y.. vol. VI, pi. VI, flg. 1, 1887. 



