
PIONOCYPRIS [Cypris vidua O. F. Miiller 1776,p.199; 1785, 
pe55,ple4,f27-9] Brady and Norman 1896,p.725 
[Invalid, as Brady and Norman 1889,p.89, and Sars 
1889a,p.53 has already designated Cypris vidua as 
genotype of Cypridopsis.] 
PIRETELLA [P. acmaea] Opik 1937,p.111 [Piretellidae by Opik; 
Hollindae-Hollininae by Schmidt 1941,p.32; 
Tetradellidae-Piretellinae by Henningsmoen 1953, 
pe217,218,226,267] Ordovician, Estonia. 
PIRETELLIDAE Opik 1937,p.110, a family to include Piretella, 
Hesperidella, Steusloffia, Pseudostrepula, and 
Rigidella. 
PIRETELLINAE Henningsmoen 1953,p.197,217,267, a subfamily of 
Tetradellidae to include Piretella, Piretopsis, 
Rakverella, Dicranella, Ctenotella, and Opikum 
(sice = Opikium). 
PIRETOPSIS [P. donsi] Henningsmoen 1953,p.218,267 (nude); 
1953b,pe43 [Tetradellidae-?Piretellinae by 
Henningsmoen] Ordovician, Norway. 
PLACENTELLA [P. delicata] Wilson 1935,p.636 [Primitiidae by 
Wilson; Drepanellidae-?Bolliinae by Henningsmoen 
1953,pe268. Devonian of Tennessee. 
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