fractured base thirteen lines; the diameter of the cup one inch, and the depth of the eup five 
lines. Other examples apparently referable to this species exhibit a diameter of from one inch 
and a quarter to one inch and a half. 
Locality and Formation.—Corniferous Limestone of Port Colborne. 
17. HELIOPHYLLUM CAYUGAENSE (Billings). 
(Plate V. Fig. 2.) 
Heliophyllum Cayugaense (Billings), Canadian Journal, new series, Vol. IV. p. 124. 
Corallum simple, turbinate, straight or curved. Septa ninety at a diameter of two 
inches; one hundred and eighty at a diameter of three inches and a half. Arched septal 
striz and spines thick and strong, separated from one another by intervals of a line or a little 
less. Calice with a flattened space at the bottom, and a septal fossette on one side. Hpitheca 
with numerous sharp encircling ridges and folds of growth. 
This species is closely related to H. Canadense (Billings), from which it is separated by 
the possession of a flattened space at the bottom of the cup, and by the somewhat greater 
remoteness of the septal striae and spines, 
Specimens with a calice of two inches across, seem to have been about five or six inches 
in length, but individuals of the species appear to have attained a much larger size. 
Locality and Formation.—Rare in the Corniferous Limestone of Port Colborne, and 
other localities in Wainfleet. 
18. HeniopHytitum Hani (Edwards and Haime). 
Strombodes helianthoides (Phillips) ; Pal. Foss. p. 10. Plate V. Fig. 13. a. 
Heliophyllum Halli (Kdwards and Haime) ; Brit. Foss. Corals, p. 235. Plate IT. 
Fig. 3, and Pol. Foss. des Terr. Paléozoiques, p. 408, Pl. VII, p. 6. 
Heliophyllum Halli; (Billings) Canadian Jowrnal, New Series, Vol. IV. Fig. 126. 
Corallum simple, broadly turbinate, cylindrical, or cylindro-conic, often variously curved. 
Septa 80 to 85, slightly twisted towards the centre. Septal ridges and spines separated by 
intervals of from half to one-third of a line, or even less. Calice circular, moderately deep, with 
a small septal fossule. Epitheca with encircling annulations of growth, but seldom exhibiting 
septal ridges when perfect, or at most very faintly. 
The form and curvature of this species are extremely variable, and the size no less so ; 
whilst the intervals between the septal spines and strice vary so much that it seems doubtful 
if much reliance can be placed on this character in the discrimination of species. The exam- 
ples of this species from the Corniferous Limestone are mostly of large size, and are not parti- 
cularly well preserved. Those from the Hamilton group are as a rule small, and occur in a 
state of exquisite preservation. 
One very marked feature in Heliophyllum Halli, as exhibi- 
ted in all the Hamilton examples except the smallest, is the 
mode of growth, which is by a peculiar form of calicular 
gemmation. When the coral has grown to a certain length, 
the epitheca gradually extends over the original calice in 
whole or in part, and a fresh corallite is produced from the 
primitive oral disc by calicular gemmation, generally from 
one side of the old cup. After this has lived for a certain 
period, a third cup is produced in a similar manner; and 
so the process may be continued, till an aged specimen may 
consist of six or eight cups arranged in a vertical series, 
each springing from some portion of the calice of.its prede- 
cessor. This mode of growth, also, causes a singular irreg- 
A ularity in the form of corals of this species, old examples 
bes ften looking like a succession of inverted cones inserted 
Heliophyllum Halli(Edw. & H.). A young a : i ° 
one into the other, whilst the curvature of the whole becomes 
specimen, from the Hamilton Formation ‘ ? - 
of Arkona. equally irregular by the bending of the successively produced. 
