362 THE DEVONIAN FOSSILS OF CANADA WEST. 
est thickness, from side to side; the least, from the ventral to the 
dorsal aspect; the diameters haying a proportion to each other of 
about ten or eleven to fifteen. The sides are narrowly rounded; the 
dorsal aspect uniformly depressed convex ; the ventral aspect more 
strongly convex than the dorsal, and most prominent along the median 
line. In the cast of the interior there is close to the aperture a 
broad, shallow constriction, showing’ either that the shell is thickened 
on the inside at this point, or that the aperture is smaller than the 
greatest size of the tube. There is also an appearance which leads me 
to suspect that the aperture is obscurely trilobed. In the specimen 
above mentioned, the chamber of habitation is one inch and a half 
in depth. The first four septa occupy one inch in length of the tube, 
and the others become nearer to each other as they approach the 
apex. The siphuncle is about two lines in thickness and close to the 
margin, but not in contact therewith, there being in one specimen half 
a line and in another about a line between it and the shell. The 
latter appears to thin with obscure encircling strie. 
A specimen seven inches in length has a dorso ventral diameter of 
sixteen lines, at about one inch from the aperture ; and it tapers to 
six lines at seven inches. The remainder to the apex is broken off 
and not preserved. The lateral diameter of this specimen cannot be 
ascertained, as it is partly imbedded in the stone. But in another, 
(a fragment) the diameters are, at the large end, 12 lines to 16 lines, 
and at two inches nearer the apex 7 to 11 lines. 
There appears to be some variation in this species with regard to 
the distance of the septa. In one specimen the first two next the 
outer chamber are only two lines distant, and in another which appears 
to belong to this species there are six septa in one inch at three inches 
from the aperture. 
Locality and Formation.—Corniferous Limestone, County of Hal- 
dimand. 
Collectors.—E. DeCew, J. DeCew. 
CRUSTACEA. 
The Trilobites that have been determined are Calymene Blumen- 
bach, Phacops bufo, Dalmanites calliteles, and Phillipsia ? crassi- 
marginata. Besides these, there are five other species belonging to 
the genera Lichas, Dalmanites, and Phillipsia,—in all nine species. 
There are also two species of Leperditia. 
