126 
tube is certainly present, and the lateral tubes spring from it, and not from one another, as I 
was at first led to believe by my examination of casts from the Corniferous. The arrangement 
of the lateral tubes also is more variable than I had imagined. Sometimes they are entirely 
produced from one side of the tube (Fig. 57 b) ; but at other times they are biserial and alter- 
nate regularly with one another (Fig. 57). The fossil differs from the typical species of Aulo- 
pora in the great proportionate length of the lateral buds, and in their regular and more or 
less symmetrical method of growth, and more especially in the fact that the apertures of the 
tubes open in the plane of growth of the entire corallum, and are neither elevated above the 
general surface, nor perceptibly expanded. 
The only species of Aulopora to which it has any affinity is 4. filiformis (Billings), but 
this is a much more robust species, with larger tubes, and much more irregular method of 
- growth, and apertures generally distinctly elevated above the general surface. 
‘As occurring in the Corniferous Limestone, Aulopora (?) Canadensis is found chiefly 
growing on the epitheca of Fistulipora Canadensis, and Diphyphyllum arundinaceum. In the 
Hamilton Formation, it affects chiefly Heliophyllum Halli and Cystiphyllum vesiculosum, and in 
both groups it is commonly accompanied by Spirorbis omphalodes. 
Locality and Formation.—Corniferous Limestone, Port Colborne, and Lot 6, Concession 
1, Wainfleet. Hamilton Formation, Bartlett’s Mills, near Arkona, Township of Bosanquet. 
158. SYRINGOPORA INTERMEDIA (Nicholson), 
Corallum lax, spreading, increasing by the production of lateral buds. Corallites eylin- 
drical, often more or less crooked, having a diameter of from one line to a line and a half, or 
rarely two lines, the lateral buds being produced at angles of from 90° to 40,° and at intervals 
of from two to four lines. No connecting horizontal processes between the corallites, but 
sometimes abortive spines or nodes. Epitheca with fine encircling striz, and irregular growth- 
swellings and geniculations. Internal structure, of infundibuliform tabule. 
In its form and mode of growth, this form agrees altogether 
with Syringopora nobilis (Billings), of which I at first believed it to 
be simply the young. The latter, however, is a much larger form, its 
corallites having an average diameter of three lines, and sometimes 
as much as five lines, and its buds being produced at longer intervals. 
S. intermedia, on the other hand, occurs in the Hamilton formation 
(S. nobilis being a Corniferous species), and though it is very abund- 
ant, I have never seen any example with a diameter exceeding two 
lines, the majority of specimens having a diameter of little over one 
Fra. 58. line. The corallites also are much more crooked and irregular, and 
Fragments of Syringopora inter. the branches are produced at much shorter intervals. Some speci- 
media (Nich.) natural size. From mens do not exhibit the internal structure, and these present a 
the Hamilton group. oy 1° ° 
resemblance to Aulopora cornuta (Billings), from. which, however, 
they are readily distinguished by not being creeping or parasitic. Upon the whole, S. interme- 
dia appears to me to be distinguished by characters of specific value. 
Locality and Formation—Common in the Hamilton Formation, Widder ; and Bartlett’s 
Mills, near Arkona, Township of Bosanquet. 
159. AmBoca@L1A umBonaATA (Conrad). 
Orthis umbonata (Conrad), Journ. Acad. Nat. Science, Philadelphia, Vol. VIIL, p. 264, 
PEE Vio 2 . 
Ambocelia umbonata (Hall), Thirteenth Report on the State Cabinet, p. 71. 
Orthis nucleus (Hall), Geol. Rep. Fourth Dist., New York, p. 180. 
Ambocelia umbonata (Hall), Pal. N. Y., Vol IV., p. 269, Pl. XLIV., Figs, 7—18. 
Since the portion of this Report treating of the Brachiopoda was written, I have come 
across two or three unmistakable examples of the ventral valve of this little shell, which if not 
identical with Spirifera Urii (Fleming), [ = P. unguiculus, Phillips], is certainly very close to it. 
Our specimens are from the Corniferous Limestone, a formation in which they do not appear 
to have been detected by Hall, and I am chiefly concerned to notice their occurrence for the 
purpose of repeating that they are entirely distinct from Productella Eviensis (Nich.), to which 
