36 
VICTORIA MEMORIAL MUSEUM. BULLETIN NO. I 
by two faint depressions at the posterior end. The border 
around the body portion is narrow, concave, and there are 
narrow extensions at the sides. 
Measurements. — The best pygidium, which may be taken as 
the holotype of the species, is 10 mm. long, and 11 mm. wide. 
Of this length, 2-5 mm, is due to the projection of the spine at 
the posterior end. A larger pygidium is 14 mm. wide, and, 
without the spine, 9*5 mm. long. The hypostoma is 7 mm. 
long and 6 mm. wide. 
This species differs from Holasaphus centropyge , Matthew, in 
having the eye much farther back on the head, a longer and 
narrower fixed cheek, and a more divergent spine on the free 
cheek. The pygidium of our species has four distinct rings on 
the axial lobe, and that of Matthew’s species only three. 
Locality . — Specimens of this species seem to be fairly common 
in an old quarry in the lower part of the Beauharnois formation, 
(Beekmantown), near the Canadian Pacific Railway station at 
St. Anne de Bellevue, Island of Montreal, Que., where the first 
specimen was found by Mr. E. J. Whittaker, The name is 
given in allusion to the writing of the Canadian Boating Song 
by Tom Moore while staying at a house not far from this quarry. 
Genus Pseudosph^erexoghus, Schmidt. 
Pseudosphjerexochus Apollo, (Billings). 
. Plate IV, figs. 1 and 2. 
Cheirurus apollo , Billings, 1860. Canadian Naturalist and 
Geologist, Vol. V, p. 322, fig. 28. — Palaeozoic Fossils of Canada, 
Vol. II, p. 413, fig. 397, 1865. 
Amphion cayleyi , Billings, 1863. Geology of Canada, p. 239, 
fig. 277. — Palaeozoic Fossils of Canada, Vol. I, p. 413, fig. 398. 
( Cheirurus” apollo was described by Billings from an im- 
perfect cranidium found at Point Levis. The collection con- 
tains a metal cast which is probably a replica of the type. On 
the same page of the ‘Palseozoic Fossils” is the figure of a 
pygidium, which in the Geology of Canada, 1863, p. 239, was 
called Amphion cayleyi. Billings states, however, that this 
