21 
so as to form a central boss or projection. Radiating septa numerous (from eighty to on® 
hundred), varying much in the extent to which they encroach upon the central tabulate area: 
External area thin, vesicular, its cells formed on the one hand by the septa, and on the other 
by a series of curved plates, which extend in an arching manner and in a direction nearly 
parallel with the axis of the goral, obliquely from the central area to the epitheca. When the 
epitheca is removed, the apertures of the cells of this external area appear on the surface in 
the form of rectangular openings directed very obliquely inwards. In specimens in which 
the epitheca is preserved, the surface exhibits encircling ridges and annulations of growth, 
varying much in their comparative remoteness, sometimes rounded, sometimes sharp-edged. 
There are also numerous cost, varying from four to six in a space of two lines in specimens 
of different sizes. A well-marked septal fossette can usually be detected. 
As already remarked, the internal structure of this species does not conform with the 
definition of Clisiophyllum given either by Edwards and Haime or McCoy ; and it seems 
doubtful if it can be retained in this genus. In most respects the species comes nearest to 
the characters of Amplexus, but it is distinguished by the presence of a cone and the posses- 
sion of an external vesicular area. The cone or central boss is certainly formed by an eleva- 
tion of the tabulee of the central area, and the condition of the septa varies very much in 
different examples which appear to be otherwise referable to this species. Sometimes the 
septa extend as far as the centre of the coral, being continued across the upper surfaces of 
the tabulee in a diminished and rudimentary form. Such examples would, perhaps, come under 
the definition of Clisiophyllum given by Milne Edwards and Haime. More commonly, the 
septa are comparatively rudimentary, and extend but a short distance from the outer wall, 
leaving the central tabulee exposed, very much as occurs in Amplexus. s 
Examples of this species from which the epitheca has been removed, may usually be 
determined by the peculiar rectangular and obliquely-descending cells of the outer vesicular 
area. It must be admitted, however, that if the internal structure is not shown it is some- 
times dificult to distinguish such specimens from examples of Blothrophyllwm decorticatum 
which have been denuded down to the central core. 
Locality and Formation.—Not uncommon in the Corniferous Limestone of Port Colborne, 
and very abundant in the same formation at Hagersville. 
10. CLISIOPHYLLUM PLURIRADIALE (Nicholson). 
Corallum simple, turbinate or cylindro-conic, straight or curved, of large size. Central 
area tabulate, the tabulz strongly elevated so as to form a median boss or projection. Radiat-s 
ing septa exceedingly numerous, alternately large and small, being about one hundred and 
twenty in specimens of an inch and a half in diameter, and rising to one hundred and eighty 
in a specimen two inches and a quarter across. The septa extend a considerable distance 
inwards, and a septal fossette is present. Surface marked with numerous rounded encircling 
folds and annulations, and also with strong and unusually well-marked septal ridges, about 
four of which occupy a space of two lines. Dimensions unknown, but great, large specimens 
having a length of half a foot or more and a diameter of nearly two inches and a half. 
This species is clearly separable from C. Oneidaense by its generally greater dimensions, 
the much greater number of its septa in examples of similar dimensions, the absence of an 
external vesicular area, and the surface characters. Whether it is truly referable to the 
genus Clisiophyllum, however, may be regarded as very doubtful—the central elevation, as in 
C. Oneidaense, being clearly formed by the tabul alone. 
Locality and Formation.—Not uncommon in the Corniferous Limestone of Ridgeway. 
Genus ZAPHRENTIS (Rafinesque). 
Corallum simple, turbinate or cylindrical ; calice deep, with a single strongly-developed 
septal fossette occupying the place of one of the septa; no columella; tabulee well developed, 
bearing upon their upper surface a series of septa, which extend from the epitheca, nearly or 
quite to the centre of the corallum. The interseptal loculi usually uninterrupted except by 
the tabulze, but sometimes interfered with by dissepiments at the circumference of the coral, 
giving rise to an outer area 6f vesicular tissue. 
The genus Zaphrentis of Rafinesque is identical with the genus Caninia of Michelin, 
and is one of the most natural groups of the Cyathophylloil corals. The most typical forms 
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