NOTES ON CYCLOCYSTOIDES 
29 
to be two very small plates in front of each sub-marginal plate. 
These small plates do not make a solid covering, but have large 
pores between them. Around the small mound which resembles 
an anal pyramid, there are five small, deep depressions, which 
may indicate the main trunks of the sinuses which extend be- 
neath the integument, as has been described. 
The great length of the plates of the sub-marginal ring on this 
side serves to distinguish the lower from the upper side of the 
animal. 
This specimen was collected by Mr. J. E. Narraway, at the 
Axe Factory quarry, Hull, Que., and is from the Prasopora zone 
of the Trenton. 
Cyclocystoibes htjronensis, Billings. 
Plate III, fig 2, 
Cyclocystoides huronensis , Billings, 1865. Palaeozoic Fossils 
of Canada, Vol. I, p. 393, fig. 369. 
This species was briefly described and very inadequately 
figured by Billings. The specimen is a large one, considerably 
weathered, and is of interest as showing well the relation of the 
radial ridges of the dorsal side to the plates of the sub-marginal 
ring. Specifically, it is easily distinguished by the great number 
of small plates, about 60, in the sub-marginal ring, and its large 
size (35 mm. in diameter). 
The sub-marginal plates differ from those of C. halli , in that 
some of them have only one, instead of two, spoon-shaped de- 
pressions on the outer half. Each plate has a narrow ridge 
leading to it, and these ridges unite as the centre is approached, 
but the system can not be made out as clearly as in the specimen 
of <7. halli from Kirkfield. They evidently unite in some such 
manner, as only 5 branches reach the centre. At one point on 
the outside of the sub-marginal ring, the plates of the vertical 
series bounding the outer wall of the circular canal can be seen, 
where they have fallen outward. Outside of them, there is a 
narrow band which has somewhat the appearance of being made 
up of imbricating plates. This is the “shagreen” border of 
HalFs description, and suggests the outer border of Agelacrinites 
hillingsi. Just what its relation to the animal was is not evident. 
