109 
radially disposed round this central point. It is to be regretted, however, that, with the im- 
perfect materials at my command, I am at present compelled to leave this and other points of 
interest in the structure of this remarkable form unelucidated. 
Locality and Formation.—Common in the Hamilton group, at Bartlett’s Mills, near 
Arkona, Township of Bosanquet. (Also common in the Hamilton Shales, at Canandaigua, 
State of New York.) 
133. TNIOPORA PENNIFORMIS (Nicholson). 
Teniopora penniformis (Nicholson), Geological Magazine, March, 1874. 
Polyzoary forming a linear flattened expansion, which probably divides dichotomously. 
The total width of the frond is about two lines, and its thickness in the middle is about two- 
thirds of a line, gradually tapering to the margin. Both sides of the ecencecium (onecertainly, 
and the other probably) are furnished with an exceedingly strong, blunt, mesial, longitudinal 
ridge or keel, the height of which is about a fourth of a line and its thickness about the 
same. On either side of the central keel are four rows of cells in alternating lines. The 
mouths of the cells are circular and prominent, ab ut five or six occupying the space of one 
line measured longitudinally. Outside the rows of cells on either side is a plain non-cellulifer- 
ous space, about one-third of a line in width, by which the margin is constituted. 
In most of its essential characters, Twniopora penniformis (fig. 46) agrees with 7. exigua, 
but it is a much stronger and more robust form, with a broader and more elevated keel, and 
possessing a marginal non-poriferous area which appears to be wanting in the latter. I have 
only fragments of the species, and am unable to state anything as to its general form of growth 
or its total dimensions. 
Locality and Formation.—Hamilton Formation, Bartlett's Mills, near Arkona, Township 
of Bosanquet. 
Genus CARINOPORA (Nicholson), 
(Canadian Journal, Vol. XIV., No. 2, and Annals of Nat. Hist., Feb. 1874.) 
Polyzoary infundibuliform, caleareous, and reticulated. The external layer of the ey- 
athiform frond is composed of regularly undulated flexuous branches which anastomose with 
one another after the manner of a Retepora so as to form a series of oval fenestrules. Exte- 
riorly, the branches are angulated or carinate and are smooth and non-celluliferous. Inter- 
nally, each branch gives origin to an enormously developed keel or vertical lamina, which cor- 
responds in direction with the branch and is directed inwards towards the centre of the funnel. 
‘The inner face of the branches thus presents a series of narrow, elevated parallel ridges sepa- 
rated by deep grooves at the bottom.of which the cells open to all appearence. The fenes- 
trules also open at the bottom of these grooves. These grooves, however, appear in parts of 
the frond to be rendered vesicular by means of a series of delicate calcareous laminze which con- 
nect together the oppe- 
sing sides of contiguous 
ridees. In some cases 
also, the inner ends 
of the ridges are con- 
nected together by a 
continuous calcareous 
membrane, so that the 
inner surface of the 
frond is completely 
closed. The cells are 
carried in alternating 
double rows upon the 
Fig. 48. inner surface of each 
Illustrations of the structure of Carinopora Hindei, (Nich). a. fragment of the exterior, branch, their mouths 
natural size ; b. portion of the same enlarged ; c. another fragment of the exterior, still fur- appearing to besituated 
ther enlarged ; d. a fragment from which the external non-celluliferous layer has been re- = 1 
ae ere «the n. enlarged ; ¢. a fragment more deeply decorticated, showing the at the bottom of the 
mouths of the cells, enlarged ; f. and g. transverse sections of the frond enlarged ; h.a por- o+ F - 1 
tion of the internal surface eateeed : i. transverse section of a single branch, ipsees ee afore-mention- 
From the Cormiferous Limestone. ed and at the base of 
