125 
“ Polyzoary adnate, attached parasitically to the exterior of corals, branching in an irre- 
gularly dichotomous manner. Cells in reality uniserial, but so disposed by the turning ot 
each cell-mouth to alternate sides as to look as if bi-serial. The terminal portion of each cell 
bent outwards; the aperture circular. The cells tubular, elongated, slightly or not at all 
expanded and not at all elevated towards their apertures. Five cells in the space of two lines : 
width of cell about one-fiftieth of an inch near the mouth. 
“ T have considerable doubts as to the affinities of this extraordinary little fossil; but 1 
think it is certainly one of the Cyclostomatous Polyzoa, and I see at present no better course 
than to refer it to Alecto, Lamoroux. When not examined closely, the fossil presents a striking 
resemblance to a Sertularian Zoophyte, exhibiting exactly the appearance of a number of 
tubular calycles or cells springing alternately from the two sides of a common canal or stem. 
When minutely looked into, however, it is seen that this is deceptive, and that the fossil con- 
sists really of an alternate or sub-alternate series of long, tubular, slightly flexuous cellules, 
each cell being nearly cylindrical, and having the terminal portion geniculated or bent out- 
wards, in such a manner that the mouths of successive cells point in opposite directions. 
“The difficulty in determining the systematic place of this fossil is much increased by 
the fact that it occurs solely in the forms of casts, ramifying in the walls of moulds from 
which corals have been removed. It is, therefore, impossible to determine what was the tex- 
ture of the coencecium, whether caleareous or corneous; whilst the lines of division between the 
cells, where they come in contact with one another, are only very faintly and obscurely indi- 
cated. The form of the aperture of the cell appears to have been circular, and its position 
terminal ; but some uncertainty attaches to both of these statements.” 
Since writing the above, I have obtained specimens of the same fossil] from the Hamilton 
group, in which the actual corallum itself is preserved, and these seem to show that the species 
is truly referrible to Aulopora, though certainly unlike the typical species of the genus. 
1p 
e 
an 
Fie. 57. 
_ Aulopora (2) Canadensis (Nich.); a. A fragment natural size; b. Cast from the Corniferous Limestone, in which 
uniserial arrangement obtains, enlarged ; c, Cast from the Corniferous Limestone, in which a biserial arrangement obtains 
d. A portion of the actual coral, from the Hamiltorf group, enlarged ; e. A fragment of the last still further enlarged. 
The examples from the Hamilton group have the form of branching calcareous corals 
which are adherent by the whole of one surface to some foreign body. ‘I'he tubes are semi- 
cylindrical or sub-cylindrical, marked with extremely fine encircling striz, and having a 
diameter of about one fiftieth of an inch. The lateral tubes are produced from the sides of the 
main tube, usually alternately on opposite sides, and generally at intervals of from. a third of 
a line to half a line. Their length varies from half a line to a line and a half, and their direc- 
tion may be nearly parallel with the main tube, or at right angles to it, but generally forming 
angles of about 40° to 50.° The apertures of the lateral tubes are not elevated above the 
general surface, and usually have an elliptical form. 
I do not yet feel satisfied that this singular fossil is an Aulopora, though the well-pre- 
served specimens from the Hamilton group secms to prove it not to be an Aleclo. A main 
