33 
constrictions of growth ; they may be straight, or more or less flexuous ; and they vary in 
their distance apart. The epitheca is marked with numerous extremely close-set and delicate 
encircling strize, together with more or less conspicuous vertical strize, which mark the posi- 
tion of the septa within. Occasionally, the corallites are united by lateral connecting pro- 
cesses derived from the epitheca, similar to those which characterise the genus Hridophyllum ; 
but these processes are always remote, and are only an occasional feature. The septa are 
from forty to forty-two, alternately large and small, and rarely encroaching upon the central 
tabulate area. The tabulee are regularly depressed and bent downwards as they pass through 
the outer vesicular zone on their way to reach the margin ; but they are sometimes more or less 
flexuous, Increase of size, so far as I haye observed, seems to be always by the production 
of lateral buds, but it is possible that calicular gemmation sometimes occurs, and Mr. Billings 
states that bifurcation of the corallites takes place occasionally. 
Very commonly the corallites of this species have attached to their surface the singular 
adnate coral which [ have described under the name of Aulopora (?) Canadensis, along with 
the tubes of a species of Spirorbis. 
Locality and Formation.—Common in the Corniferous Limestone of Port Colborne, and 
Lot 6, Con. 1, Wainfleet ; also ‘in various localities in the townships of Walpole, Oneida, 
Cayuga, and Wainfleet ” (Billings). 
DIPHYPHYLLUM STRAMINEUM (Billings). 
(Plate V., Fig. 6.) 
Diphyphyllum stramineum (Billings), Canadian Journal, New Series, Vol. iv., p. 135. 
(Compare Diphyphyllum gracile (McCoy), British Pal. Foss. p. 88, figs. d, e, f). 
»* Corallum forming large masses of cylindrical tubes, averaging two lines in diameter, and 
either so closely aggregated as to be nearly in contact, or separated from one another by inter- 
vals of from one to five lines, the distance varying in different clusters and in different parts 
of the same. Sometimes numerous single tubes occur scattered through the rock, which were 
probably derived from some disintegrated group. ‘The tubes are either straight or flexuous, 
smooth, or annulated by short encircling folds of growth, the surface striated longitudinally 
by the outer edges of the septa. ‘I'he latter are about forty in number, and do not reach the 
centre. The transverse diaphragms are well developed, slightly convex in the centre, and 
appear to be suddenly turned down on approaching the margin. The outer vesicular area is 
thin, seldom exceeding one-sixth of the whole diameter. The central area altogether occupied 
by the transverse diaphragms ; sometimes in well-preserved specimens, the septa may be seen 
extending about half way to the centre, upon the surface of some of the diaphragms, but in 
general they are confined to the outer area. In the more dense colonies, the corallites often 
inosculate, and are sometimes connected by lateral ;processes, as in the species of the sub- 
genus Hridophyllum ” (Billings). 
I doubt if the distinctness of this species from Diphyphyllum gracile (McCoy) can be 
maintained. The distinction given by Mr. Billings is that the septa of the latter are alter- 
nately large and small, whereas in D_ stramineum they are all nearly equal in size; but it may 
be questioned if this distinction would be alone sufficient to separate the two forms. At any 
rate, I have found in the Corniferous Limestone, a number of specimens which agree with D. 
gracile in most respects, and which [ shall, therefore, describe under that name. 
Locality and Formationn—Common in the Corniferous Limestone of Port Colborne and 
Lot 6, Con. 1, Wainfleet. 
28, DIPHYPHYLLUM GRACILE (McCoy). . 
(Plate: V>" Bigs! 5.) 
Diphyphyllum gracile (McCoy), Brit. Pal. Foss., p. 88, figs. d, e, f. 
Corallum forming colonies of cylindrical, straight, or flexuous corallites, the diameter of 
which varies from two to three lines, being most commonly about two lines and a half. Surface 
with annulations of growth, and vertical lines marking the position of the septa. These latter 
