1915] PALAEOZOIC FossILs FROM HUDSON Bay. 45 
mum diameter 22 mm.; tetrameral symmetry clearly shown in the 
septal furrows on the exterior; at a diameter of 16 mm. there are about 
45 primary septa showing well marked tetrameral symmetry and pre- 
- senting very nearly the appearance of Plate IX, Figure 2 of Lambe’s 
work. The long primary septa reach the middle, and although much 
thickened appear to be somewhat twisted together. The secondary 
septa are very poorly developed and can scarcely be observed in the 
stereoplasma connecting the peripheral ends of the primaries. The 
vertical section, owing to secondary thickening, is very poor and only 
faintly reveals the presence of irregular tabule. 
Another specimen is somewhat larger than the above, and shows the 
same pronounced tetrameral structure. The inner ends of the septa 
are much curved, particularly the shorter ones, which seem in some 
cases to unite. Towards the periphery of the corallite, the interseptal 
elements more resemble upwardly directed dissepiments, but towards 
the centre of the coral they cannot be described as other than tabule, 
although they are very curved and incomplete. 
None of the specimens afford any evidence of the character of the 
calyx. It is apparent that the form only distantly resembles Z. stokesi: 
the secondary septa are too short and the tabulae are too badly defined, 
nevertheless I am of the opinion that our specimens approach more 
closely to this species than to any other described form: it seems ad- 
visable, in the absence of better material, to ascribe the specimens 
provisionally to Z. stokest. 
Locality—Assina rapids and vicinity, Severn river, District of Patricia, Ont. 
Horizon—Silurian. 
Nos. 292 and 293 S. Royal Ontario Museum of Palaeontology. 
INCERTAE SEDIS 
A fragment of limestone contains several broken corallites of the 
general aspect of Pycnostylus or Amplexus. The apparent internal 
diameter of the tubes is about 2 mm., while the external diameter varies 
up to7mm. This outer annulus consists of solid carbonate of lime quite 
structureless: it is impossible to say whether it is part of the corallite 
or whether it represents secondary calcite deposition. The tube is 
crossed by distinct, flat, tabule at intervals of 1.5 mm. Some of the 
corallites show short but distinct septa, while others are without these 
structures. 
If we assume that the thick outer wall is due to secondary deposi- 
tion the form may be ascribed to Pycnostylus, but to a species con- 
siderably finer in structure than P. guelphensis. It is possible that the 
