LAMELLIBRANCHIATA. 621 
Cunearoya.] 
Type: Cuneamya miamiensis Hall and Whitfield. 
This genus is represented in my cabinet by no less than sixteen, mostly unde- 
scribed, Lower Silurian specific forms, all of which, saving the two about to be 
described, were found above the top of the Trenton at Cincinnati and other localities 
within a radius of forty miles from that city. Several of these species are represented 
by casts of the interior in as fine a state of preservation as could be desired, and yet 
in no case was it possible to reach any satisfactory conclusion respecting the 
character of the muscular and pallial impressions. Under the circumstances it is 
not unlikely that the claim of the authors of the genus that the pallial line is simple, 
may be nothing more than the expression of their opinion and not the record of an 
observed fact. In their description of the genus Hall and Whitfield state also that 
posterior to the external ligament “the margins of the valves overlap each other to 
the extent of the cardinal line.” This may be true of the specimens studied by them 
but, except in several cases where it is evidently the result of accident or compres- 
sion, it is certainly not true of any specimen seen by me that is sufficiently perfect 
to admit of judgment on the point. The statement, therefore, wants confirmation 
before it can be accepted as a fact. So far as my own observation is concerned, | 
am obliged to dissent from such a view, especially as regards C. miamiensis the type 
of the genus, of which several specimens that seem to have retained the valves in a 
perfectly normal relation, have the escutcheon divided equally by the straight con- 
tact margins of the valves. 
As regards the external ligament, it is preserved by only two specimens seen by 
me. One of these belongs to C. curta Whitfield, the other to C. coriformis Miller. It 
is elongate (almost linear), occupies about one-third of the width of the escutcheon 
and extends from the beaks backward a little more than one-third of the length of 
the escutcheon. The same specimens preserve also something like a ligament over 
the margins of the valves in the lunule. 
The affinities of the genus are almost certainly with Grammysia as that genus is 
defined by Hall in his great work on Devonian Lamellibranchiata (Pal. N. Y., vol. v, 
pt. 1, pp. xxx and 358-354.) The principal difference between the genera as now 
recognized lies in the hinge, this being weak and edentulous in Cuneamya while it is 
stronger and presents one or two cardinal folds in at any rate the typical forms of 
Grammysia. Shells probably belonging to this genus have been referred to Sedg- 
wickia and Leptodomus, but as it seems, upon very insuflicient grounds, the types of 
those genera, as defined by McCoy in 1544, (Synopsis Carb. Foss. Ireland) being of a 
widely different nature. The new genus Saffordia is distinguished by its peculiar 
hinge, much smaller beaks, and strongly defined anterior muscular scar, 
