SYNOPSIS OF GENERA. 
XXXV 
Panenka, Barrande (Syst. Sil. de la Boheme, pt. 1, vol. vi, p. 128. 1881). 
Shell equivalve, more or less inequilateral, transversely or longitudinally 
elliptical or sub-circular. Beaks prominent and incurved. Cardinal line straight 
or arcuate. In some species there is a small triangular area beneath the beaks. 
Lunule sometimes present. 
Test thin. Surface marked by lines of growth, and usually by well-developed 
radii. Interior unknown. 
The species referred to this genus were formerly grouped under the genus 
Cardiola, from which they differ as shown by Barrande in their more expanded 
superior margins, and surface ornaments. Illustrations of a species of Cardiola 
{C. jluctuans, Barr.), are introduced on plates lxx and xciv, for comparison with 
the species of Panenka and allied genera. 
Examples: Panenka multiradiata, pi. lxix, fig. 5; pi. xciv, fig. 18. 
Panenka Lincklani, pi. lxix, figs. 12-14. 
Panenka radians, pi. lxix, fig. 9. 
Panenka equilatera, pi. lxix, fig. 4; pi. xciv, fig. 17. 
Glyptocardia, n. g. [Type, Venericardium retrostriatum, von Buch;=Car- 
dium palmatum, Goldfuss;=Avicula speciosa, Hall.] 
Shell small, equivalve, inequilateral, broadly elliptical or sub-circular. Beaks 
anterior to the middle, incurved. 
Surface marked by strong radiating plications and by concentric striae which 
are often lamellose and arching over the radii. Interior unknown. 
The small shells for which this genus has been proposed, are of very wide 
distribution, and have been referred by various later writers to the genus Car¬ 
diola, from which they differ in their expanded cardinal margins, their surface 
sculpturing, their minute size, and absence of a cardinal area beneath the 
beaks. 
Example: Glyptocardia speciosa, pi. lxx, figs. 2-9; pi. lxxx, fig. 10. 
