Pussella Danielopol is an interstitial bairdiid and the end member of the regressive evolutionary series represented by species of
Anchistrocheles. Its special features result from small size and adaptation for the interstitial habitat. Resemblances to Cytheracea are due to convergence. A second species of
Pussella and three new species of
Anchistrocheles are described.
A. acerosa (Brady) is re-illustrated, and the soft parts of
A. angulata (Brady) are described for the first time.