CORALS OF THE CORNIFEROUS LIMESTONE. 233 



ness of about two lines, less or more. A.t first sight one would imagine 

 that the mass had been fixed by its smaller end, the broader extremity- 

 being concave, and apparently having had the corallites opening on this 

 surface. On the contrary, however, a close examination has satisfied me 

 that the reverse of this is really the case. The coral must in reality 

 haye been free, and the broad concave end must have been covered with 

 an epitheca which has now disappeared. The calices, therefore, must 

 have opened over the entire convex surface of the cone. That this is the 

 real state of the case is shown, amongst other proofs, by the fact that the 

 entire pointed end of the cone is uninterruptedly covered by the calices, 

 rendering it impossible that the mass can have been attached at this 

 point. 



The species to which, at first sight, F. invaginata bears the closest re- 

 semblance is F. turbinata, Billings, but this resemblance ceases the mo- 

 ment the former is held in its proper position. The latter species, also, 

 is fixed by its pointed base, and has its convex sides covered with an 

 epitheca, whilst the corallites are destitute of septa, and the mural pores 

 are uniserial. The present species, on the other hand, had its pointed 

 end directed upwards, and possessed well-developed septa and biserial 

 mural pores. The septa of the corallites are apparently from six to 

 twelve in numbter, but owing to the silicification of the mass they can 

 not be counted with accuracy. The tabulae, also, are only shown over a 

 portion of the mass, but they appear to have the characters of Favosites 

 (^Emmonsia) hemispherica, being numerous, close-set, and incomplete, and 

 often interlocking by their free ends. From the ordinary forms of 

 Favosites the present species is sufiiciently separated by its peculiar form 

 and mode of growth, and its well-developed septal system. 



Position and locality : Corniferous limestone, Marblehead, Ohio. 



Genus OYSTIPHYLLUM, Lonsdale, 1839. 

 (Silurian System, p. 691.) 



Cystiphyllum vesiculosum, Goldfuss. 



Oyathophyllum vesiculosum, Goldfuss; Petref., p. 58, pi. 17, flg. 5, and pi. 18, flg. 1. 



Cystiphyllum vesiculosum, Phillips; Pal. Foss., p. 10, pi. 4, flg. 12, 



Cystiphyllum vesiculosum, Milne Edwards and Haime ; Pol. Foss. des Terr. Pal., p. 462. 



Cystiphyllum vesiculosum, McCoy; Brit. Pal. Foss., p. 71. 



Cystiphyllum vesiculosum, Nicholson ; Eept. on the Palaeontology of Ontario, p. 37, fig. 8. 



Corallum simple, elongated, turbinate, or cylindro-conic, sometimes 

 almost cylindrical. Epitheca thick, with encircling striae and folds of 

 growth, the latter being sometimes rounded, sometimes sharp-edged and 



