982 THE DEVONIAN FOSSILS OF CANADA WEST. 
Atuyris (?) Cuiée.—JN. Sp. 
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Fig. 45. Fig. 46. Fig. 47. 
Fig. 45. Athyris Chloe.—Ventral valve. Fig. 46.—Side view. 
Fig, 47.—Dorsal view. 
Description.—Transversely sub-oval; greatest width usually about 
the middle, sometimes a little above or below; front margin often 
with a rounded projecting lobe in the middle; both valves convex. 
Ventral valve with a concave mesial sinus which occasions a lingui- 
form projection in the middle of the front margin, and becomes 
obsolete at about half the length of the shell; umbo well defined ; 
beak closely incurved down to the umbo of the dorsal valve, usually, 
if not always, perforated at the tip by a small circular aperture. 
Dorsal valve with a rounded mesial fold which elevates the middle of 
the front margin and becomes obsolete at about half the length. 
Surface with somewhat obscure rounded but apparently much de- 
pressed, simple or undivided radiating ribs, of which there are on an 
,average in the specimens examined, three in the width of one line. 
There are also, especially towards the front margin, a few squamose 
rings of growth. There appear to be some fine concentric strie, but 
the surface in the specimens is not quite perfect. 
Width, from five to nine lines; length, a little variable, according 
to the greater or less developement of the mesial fold. 
In one specimen with the fold large, the length is seven lines to a 
width of nine lines. 
In this species I have detected no appearance of an area, but in 
perfect specimens the hinge-line is extended to three-fourths the 
width of the shell, and in such cases the cardinal angles, although 
rounded, are elevated and much compressed. 
Locality and formation.—Lot No. 26, con. 3, Bosanquet. Hamil- 
ton Shales. 
Collectors.—A. Murray, J. Richardson. 
(To be continued.) 
