27 
SS SEES SS a EO 
cups in different directions. True parietal gemmation, on the other hand, [ have never 
noticed to occur in this species. As a similar mode of increase exists in Cystiphyllum 
vesiculosum, a8 occuring in the Hamilton Group, and as it has not, so far as I know, been 
observed in the examples of H. Halli from the Corniferous Limestone, it seems possible that 
itis a habit of growth induced by some peculiarity in the surroundings of the coral—such, for 
instance, as the slow but regular deposition of fine clayey sediment. 
Heliophyllum Halli is very closely allied to H. Canadense, and I should be inclined to doubt 
if any distinction of importance between the two species can be maintained. Large examples 
of H. Halli, such as occur in the Corniferous, are separated from H. Canadense by their more 
shallow calice, the comparative closeness of the septal strie, and their cylindrical or cylindro- 
conical form ; but young specimens of H. Halli are often very broadly expanding and turbi- 
nate, and the intervals between the septal spines and strie do not appear to be constant. 
Small examples of Heliophyllum Halli have a length of half or three-quarters of an inch, 
with a diameter of calice of from three-quarters of an inch to an inch and a quarter. Large 
examples may have a length of from five to six inches, with a diameter of calice of two inches 
and a half. There are also more cylindrical specimens, apparently not separable from this 
species, which may have a length of two inches or over, with a diameter of calice of not more 
than from three-quarters of au inch to an inch. 
Locality and Formation.—Corniferous Limestone of Port Colborne ; Con. 1, lot 6, Wain- 
fleet; Hagersville. Extraordinarily abundant in the Hamilton Formation of Bosanquet, along 
the course of the Riviere aux Sables. Also in the Devonian Limestone of Devonshire, 
England (Phillips, and Edwards and Haime). 
19. HeELIOPHYLLUM SUB-C@SPITosuUM (Nicholson). 
Heliophyllum sub-cespitosum (Nicholson), Geological Magazine, Feb., 1874. 
Corallum, small, simple or compound, cylindrical, or slightly expanding towards the 
calice. Arched septal strize and spines from a third to aquarter of a line apart. Calice oval 
or circular, shallow. Septa apparently sixty in number, at a diameter of eight lines. Epi- 
theca with numerous annulations and constrictions of growth. Occasional 
individuals, with the other characters of the species, appear to be simple, 
but the majority of examples increase by the production of lateral buds. 
The new corallites thus produced are few in number (generally not more 
than one, two, or three), and are directed upwards nearly in the direction 
of the parent corallite.- In some cases calicular gemmation appears also 
to occur. 
H. sub-cespitosum has a general resemblance to Cyathophyllum ceespi- 
tosum of Goldfuss ; but the presence of well-marked septal strize and septal 
spines proves it to be a true Heliophyllum. The latter species also is 
*« fasciculated or astreeiform,”’ and increases principally by calicular gem- 
mation ; whereas H. sub-cespitosum never produces sufficient buds to 
form aggregations of any size, and the increase is principally by lateral 
gemmation. It is, further, distinguished from the other forms of Helio- 
phyllum by its comparatively smali size, its cylindrical form, and its mode 
of growth. H. proliferum (Nich.) increases in the same way, but is a 
much larger species, and is distinguished by other characters as well. 
Young individuals of H. swb-ccespitosum are usually strongly nodulated 
with irregular growth-swellings, and have a length of from half an inch 
to an inch, with a diameter at the cup of from two to three lines. Large 
individuals have a length of from two to three inches, with a diameter of 
calice of from eight to ten lines. 
Fig. 5. 
” all = iQ. . . . . . 
eee eh). Tacitca _ Locality and Formation.—Common in the Hamilton Formation at 
Formation, Arkona. —- Bartlett’s Mills, near Arkona, in the Township of Bosanquet. 
20. HELIOPHYLLUM PROLIFERUM (Nicholson '. 
Corallum large, simple or compound, growing socially in particular localities, where 
numerous individuals occur together nearly in contact though not organically connected. 
Form cylindrical, with numerous irregular growth-swellings in the majority of instances. 
