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. fluduans, Barr.), are introduced on plates Ixx and xciv, for comparison with 

 the species of Panenka and allied genera. 



Examples : Panenka multiradiata, pi. Ixix, fig. 5 ; pi. xciv, fig. 18. 

 Panenka Lincklceni, pi. ixix, figs. 12-14. 

 Panenka radians, pi. Ixix, fig. 9. 

 Panenka equilatera, pl. Ixix, 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, pl. Ixx, figs. 2-9 ; pl. Ixxx, fig. 10. 



