146 
Case and 
Column of 
Drawers. 
SILURIAN. 


Reference to McCoy's 
Synopsis: and Figures of Genera. 
Names and References; Observations, &e. 


FC | 
Ge 
Gd 


Leptena, p. 243. 
Lepiena, p. 244. 
1} 
0) 
a 
Leptena, p. 
Leptena, p. 243. 
bo 
_ 
Or 
Leptena, p. 


Strophomena, Rafinesque. Easily distinguish- 
ed from Orthis by the broad expanded form 
—one valve being often bent on the other, 
and so flat as to leave very little room for 
the animal. The general characters are 
much the same as in Orthis. But the car- 
dinal process is invariably double, not single. 
Leptagonia, McCoy, is only a Strophomena. 
And the Professor has placed all this genus, 
natural as it is, under the general term 
Leptena, Dalman, which is best restricted, 
as Davidson and myself have done, to the 
involute species with long, instead of square 
dorsal muscles. 
Strophomena euglypha, Dalman (Siluria, 2nd 
ed. pl. 20, fig. 19). Davidson, Lond. Geol. 
Journ, Vol. 1. pl. 12, figs. 1—4?). Most com- 
mon. The dorsal valve bends down over the 
ventral, which is bent backwards. 
Strophomena funiculata, McCoy (Orthis, Sil. 
Foss. Ireland, pl. 3, fig. 11. Davidson, Lond. 
Geol. Journ. t. 12, fig. 6, Siluria, 2nd ed. 
p. 251). Bent in the reverse way to S. eugly- 
pha, and a miniature copy of that species. 
Strophomena Ouralensis, De Vern. (Geol. Russ. 
t. 14, fig. 1, S. imbrex, Davidson, and Sal- 
ter, Siluria, Foss. 58, fig. 6, not of Pander). 
Gently curved, the ventral valve the convex 
one. This differs from Pander’s 0. imbrez, 
which is narrower, and abruptly bent down. 
The interior is beautifully shewn in Dayid- 
son’s figures. 
Strophomena filosa, Sow. sp. (Orthis, Sil. Syst. 
t. 13, fig. 12, Siluria, 2nd ed. pl. 20, fig. 21, 
Davidson, Lond. Geol. Journ. Vol. 1. p. 62). 
A common flat species, beautifully striate. 
Strophomena Pecten, Linn. sp. (Anomia, Syst. 
Nature, Orthis Pecten, Siluria, 2nd ed. Foss. 
58, fig. 8. Davidson, Introd. Foss. Brach. 
t. 8, fig. 163, &c.). Very common in Silu- 
rian and Upper Cambrian rocks. 



Numbers and Localities. 

b. 781, a. 743, interior of 
dorsal valve; a. 744, a. 745, 
outside of ventral valve ; 
a. 746, outside of dorsal 
valve, Dudley, F.C. 
b. 775, Dudley, F.C. 
b. 776, Dudley, F. C. 
b.778, Dudley, F.C.; b.779, 
Keeper's Lodge, Golden 
Grove, Llandeilo. 
b. 780, Dudley, F.C.; 
b. 783, Myddleton Park, 
Caermarthen. 
