SVRATKINA Pokorny, 1956

 

 

Type species: Discorbis tuberculata (Balkwill and Wright) var. austroliensis Chapman, Parr, and Collins. 1934 (*543), p. 563; OD.Svrakina Pokorný. 1956(*2445), p. 257.Test trochospiral, biconvex, spiral side evolute, six to seven crescentic chambers in the final whorl, sutures oblique and curved. umbilical side involute, sutures radial and slightly depressed around the closed umbilicus, periphery rounded; wall calcareous, coarsely perforate, the large pores opening at the cen­ter of small tubercles that cover both sur­faces; aperture an elongate oblique opening in a slight depression extending from near the umbilicus up the face of the final chamber about halfway to the periphery. U. Cretaceous (Maastrichtian) to Holocene; Australia; Europe; North America.