THE DEVONIAN FOSSILS OF CANADA WEST. 267 
The following figures exhibit the difference between the generic 
forms of Stricklandia and Pentamerus. 
Fig. 88. Fig. 89. Fig. 90. 
Fig. 88.—Stricklandia lens, dorsal view. 
Fig. 89. The same side view, shewing that the valves are nearly equal in size, 
Fig. 90.—Pantamerus Knightii, side view shewing the great difference i the size of the 
valves. 
This genus ranges from the Middle Silurian up to the Devonian. 
It includes three English species long known under the names of 
Pentamerus lens, P. liratus, and P. laevis. In Canada we have 
these three in the Clinton group at Anticosti, and also Stricklandia 
Gaspensis, (Niagara group) Gaspé, S. Canadensis (Clinton group) 
Thorold, C. W., S. brevis, perhaps a variety of the latter (Clinton) 
Anticosti. Stricklandia elongata is the only species known to me in 
the Devonian rocks. 
STRICKLANDIA ELONGATA. ( Vanuxem.) 
PENTAMERUS ELONGATUS.—(Vanuxem.) Geology of the Third 
District of the State of New York, p. 132. 1842. 
PENTAMERUS ELONGATUS.—(Hall.) Geology of the Fourth District 
of the State of New York, No. 34, Fig. 1. 
MEGANTERIS ELONGATUS.—(Hall.) Tenth Annual Report of the 
Regents of the University of the State of New York, p. 123. 
1857. 
RENSSELHRIA ELONGATA.—(Hall.) Twelfth Annual Report of the 
Regents of the University of the State of New York, p. 38. 
October, 1859. 
Description.—Elongate-oval, somewhat variable in form, the sides 
convex, as in the above figure, or nearly straight and parallel, and in 
the latter case the front truncated or nearly straight. Valves varying 
in the amount of their convexity, sometimes nearly cylindrical above 
