214 Frederick Chapman: 



Genjis Favosites, Lamarck. Sub-genus Emmonsia. Edwards 



and Haime. 



Favosites (Emmonsia) spinigera, sp. nov. 



Description. 1 — Corallum massive, probably roughly dome- 

 shaped. Corallites prismatic with distinct double walls, some- 

 times hardly in contact ; somewhat irregular in width, varying, 

 from .8 to 1.8mm. Tabulae numerous, about 8 in the space of 

 5mm., of two kinds, complete and incomplete. The former are 

 thin and mainly horizontal, but some are convex and others are 

 concave or even occasionally oblique. The incomplete tabulae 

 or squamulae are thick at the base, tapering to a thin edge and 

 often strongly curved, extending nearly halfway across the tube.. 

 Septal spines long, about 8 in the cycle. Mural pores large, rare,, 

 disposed along the middle of the prism wall. 



Affinities. — That this striking species falls into the subgenus 

 Emmonsia is evident from the presence of numerous incomplete 

 and spinelike tabulae seen in section. It differs from Favosites 

 {Emmonsia) hemispherical Yandell and Shumard, 2 from the 

 Upper Silurian and Devonian of Ontario, in having an equal 

 number of complete and incomplete tabulae, and in the single- 

 row of large mural pores, whereas the Canadian specimens have 

 a double row of small ones. 



In F. grandipora, Eth. fil. 3 , we have some of the characters- 

 seen in the above species, as in the spiniform tabulae, though 

 not so well developed; the mural pores are also large and uniserial, 

 as in F. (E.) spinigera, but the breadth of the corallites in the 

 latter is nearly twice as great. 



Observations. — Nicholson held the view 4 that Emmonsia should 

 be regarded as of subgeneric value only, for some specimens, 

 of a species show complete tabulae, whilst others have both com- 

 plete and incomplete. Fraipont on the other hand regarded 

 Emmonsia as a valid genus and pointed out the general trend 

 of tabulate structure in the Favositid and allied corals, which 

 pass from the horizontal character in the Silurian and Devonian. 



1. The description is based on a slice of the coral, the original specimen 

 of which has been mislaid. 



2. Contrib. Geol. Kentucky, 1847, p. 7. See also Nicholson, Pal. Tabu- 

 late Corals, 1879, p. 67, pi. III., figs. 3, 3a, b. 



3. Rec. Austr. Mus., vol. I., No. 3, 1890, p. 61, pi. VIII.. figs. 6-9. 



4. Pal. Tab. Corals, 1879, p. 41. See also remarks by R. Etheridge- 

 (junr.) on the same point in Rec. Geol. Surv., N.S. Wales, Vol. VI., pt. 3„. 

 1899, p. 167. 



