THE DEVONIAN FOSSILS OF CANADA WEST. 361 
Cyrroceras AMmMon.—(N. Sp.) 
Description.—Six to eight inches in length ; section nearly circular; 
rather abruptly curved; a specimen, six inches in length, forming a 
half whorl, which would lie in a circle of four inches in diameter ; 
the apical three inches, curved with a radius of about one inch and a 
half, more gently curved towards the aperture. Tube tapering from 
a diameter of fifteen lines at the larger extremity, to six lines at the 
smaller, in a length of six inches. 
The shell of this specimen is beautifully ornamented by strongly 
elevated, encircling, waved ridges, of which there are forty-seven in 
the length of five inches and a half; these are distant from each other 
about three lines at the larger extremity, becoming gradually more 
and more approximated towards the smaller end—where the last two 
are scarcely a line distant. In their course round the shell, the ridges 
are undulated by short, zig-zag curves, from half a line to two lines 
wide, and one line, or a little less, in depth. In crossing the median 
line of the ventral aspect, they make a deep curve towards the apex, 
two lines deep near the aperture, and one line and a half wide, becom- 
ing gradually less as the diameter of the shell decreases. The ridges 
project abruptly from the surface of the shell to the height of half a 
line, the intervening spaces are flat, and nearly smooth, or with appar- 
ently obscure, concentric striz. 
The deep flexures of the encircling ridges along the ventral aspect 
seem to shew that the siphuncle is situated close to the margin on 
that side. The septa have not been observed. The aperture is not 
preserved in the specimen, but it is most probably circular. 
The above description is founded upon a single specimen, which is 
' nearly perfect, and has the shell preserved—but silicified. 
Locality and Formation.—Township of Rainham, Corniferous 
Limestone, 
Collector.—E. De Cew. 
Cyrtroceras Betus.—(N. Sp.) 
Description.—Six to eight inches long ; curved so as to make about 
half of a whorl, of which the diameter would be about six inches. 
In a specimen seven inches long, measuring along the ventral aspect, 
the curve corresponds very nearly to that of a circle with a radius of 
three inches, and the remainder to one with a radius of about two 
inches. The cross section of the tube is transversely oval ; the great- 
Vou. VI. 2B 
