GENERA OF FAVOSITIDrE. 57 



Favositcs Forbesi, Milne-Edwards and Jules Haime, Brit. Foss. Cor., p. 258, 



PL LX., figs. 2-2 g, 1854. 

 ,, hasaltica (pars), Billings, Canadian Journ., new ser., vol. iv. p. 106, 



1859. _ 

 „ Forbesi, Nicholson, Report on the Palaeontology of Ontario, p. 48, 



PL VII., fig. 8, and PL VIIL, fig. 4, 1874. 

 ,, tiiberosus, Rominger, Fossil Corals of Michigan, p. 30, PL IX., figs. 



I, 2, 1876. 

 ,, Fo?'besi (?), Hall, Twenty-eighth Ann. Rep. on the State Cabinet of 



N.Y., PL IV., figs. 6-15 (not described), 1876. 



Spec. Chai\ — Corallum composite, forming globular, discoidal 

 or clavate masses when young, and becoming when adult more 

 or less irregularly spheroidal, hemispherical, or pyriform in 

 shape, the diameter of the colony varying from less than 

 half an inch up to two, three, or more inches. The colony 

 may be attached to some foreign body by a limited portion 

 of its base, having the whole of the rest of its surface covered 

 by the calices ; or the lower surface may be covered by a con- 

 centrically-striated epitheca, and the calices may be confined to 

 the upper surface only. The corallites are prismatic, often 

 approximating to a cylindrical form, comparatively thick-walled, 

 of more or less conspicuously unequal sizes, the larger and more 

 cylindrical corallites having a variable number of smaller and 

 more angular tubes intercalated among them. The large 

 tubes vary from one to two lines in diameter (being some- 

 times less than one line), and the small tubes have a dia- 

 meter of from one-fiftieth of an inch to half or three-quarters 

 of a line. Mural pores apparently in two or three alternating 

 rows on each prismatic face of the corallites. Septa obsolete, 

 or represented by longer or shorter radiating spines arranged 

 in vertical rows. Tabulae, typically, complete, but sometimes 

 reduced to or accompanied by rudimentary horizontal laminee. 



Obs. — F. Forbesi, E. and H., like F. Gothlandica, Lam., is a 

 comprehensive type - form, with well - marked characters, but 

 giving rise to a series of varietal forms, which, from one point 

 of view, may be regarded as distinct species. Regarded in 

 a broad aspect, F. Forbesi is distinguishable from F. GotJilan- 

 dica, Lam., and its immediate allies by the conspicuous in- 



