PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 21 
**D. magnificus (Billings) = O. magnifica Billings 
Didymelasma abruptum Cooper 
Dinorthis brownt Wilson 
D. iphigemia (Billings) 
D. iphigenia minor Wilson 
D. pectinella (Emmons) 
D. cf. D. p. sweeneyi (N. H. Winchell) = Dinorthis cf. D. sweeneyi (N. H. Winchell) 
D. regularis Wilson 
**Doleroides gibbosus (Billings) 
**D. pervetus ottawanus Wilson = Doleroides ottawanus Wilson 
**Fichwaldia subtrigonalis Billings 
**Glyptorthis bellarugosa (Conrad) 
Hesperorthis tricenaria (Conrad) 
Microtrypa altilis Wilson 
M. ? nasuta Wilson 
**Opikina ampla Wilson 
**O, gloucesterensis Wilson 
**O. hemispherica Wilson 
**O, inquassa (Sardeson) 
O. ovalis Wilson 
O. platys Wilson 
0. rugosa Wilson 
**O, rugosa avita Wilson 
**O, septata borealis Wilson 
**O, sinclairi Wilson 
O. subtriangularis Wilson 
O. transitionalis (Okulitch) 
**O, tumida Wilson 
Platystrophia amoena McEwan 
P. a. longicardinalis McEwan 
P. trentonensis McEwan 
**Plectorthis ottawaensis Wilson 
**P_ pulchella Wilson 
Rafinesquina alternata (Conrad) 
**R. a. alata Wilson 
**R. a, intermedia Wilson 
R. a. plana Wilson 
**R. a. semiquadrata Wilson 
**R. a. transversa Wilson 
R. hullensis Wilson 
**R. lennoxensis Salmon 
R. opeongoensis Wilson 
**R, orleansensis Wilson 
R. patula Wilson 
**R. robusta Wilson 
**R. subcamerata Wilson 
R. ottawaensis Wilson 
**R. salmoni Wilson 
**R. sinuata Wilson 
Rhynchotrema increbescens (Hall) 
R. ottawaense (Billings) = Drepanorhyncha ottawaensis (Billings) 
Schizocrania filosa (Hall) 
Skenidioides billingsi Schuchert and Cooper 
S. ? merope (Billings) 
