NIAGARA GROITP. 



149 



Genus TREMATOPORA(noi;, ^en.). 



[Gr. Tpri^ang, foramen, and -jfopo?, pora.] 



Ramose or incrusting corals, composed of tubular cells more or less closely arranged ; in- 

 termediate spaces solid on the surface, but in the interior transversely septate ; cells not septate ; 

 apertures oval or circular, often contiguous, margined by a thin elevated border or calicle, 

 which, on the lower side, is often prominent or labellate. 



The corals of this genus bear a close resemblance to the preceding, and indeed it is difficult 

 to indicate to which of the two genera some of the species belong. The prominent surface 

 characters by which Trematopora differs from Callopora are the more conspicuous calicle or 

 elevated rim around the aperture, and the solid interspaces on the surface, where the cells are 

 not contiguous. Like Callopora, the cells are often separated from each other and contiguous in 

 the same species ; and in transverse sections of the stems there is no means of distinguishing 

 the two, the mode of growth in each being similar. 



These corals have often a close resemblance to Ch^tetes or Favosites ; but the tubular 

 cells with the walls rarely contiguous, and the circular or oval openings margined by a dis- 

 tinct calicle, sufficiently show that they are different. 



Corals of this character have been referred to Ceriopora of Goldfuss, to Millepora and 

 Verticillipora, to neither of which genera do they strictly belong. They are for the most 

 part ramose, with the branches generally solid, and the tubular cells reaching to the centre j 

 in others the stems are hollow, and in rare instances, and particularly at the commencement 

 of their growth, they are incrusting. It seems necessary, in order to insure definiteness, to 

 separate several species possessing the essential characters noticed, rather than to place them 

 under genera which have been established for the reception of recent corals, or for those of 

 modern geological epochs, and which do not strictly correspond in character. 



539. 1. TREMATOPORA TUBERCULOSA (n. sp.). 



Pl. XL A. Fig. la-g. 



Corallum irregularly ramose ; branches stout, often more or less flattened ; surface tuber- 

 culous ; cells tubular, usually solid ; apertures distinctly oval, more or less closely arranged, 

 often contiguous, though preserving a distinct oval form ; calicles spinulose ; section of the 

 stem showing a solid prismatic or fibrous structure ; intercellular spaces septate. 



This species is readily recognized by the strong nodose branches, closely and often irregu- 

 larly arranged openings of the cells upon the surface, and a close fibrous structure radiating 

 from the centre in transverse sections of the stems. The apertures are not always closely 

 arranged, nor are the longest diameters always placed in the longitudinal direction of the stem 

 or branches ; but these variations are usually inconsiderable, the general aspect being that 

 given above. In the smaller terminating branches the nodose character is not always developed^ 



