PLACENTULA [Primitia excavata Jones and Holl 1869, p.222, 
ple15,f.l0a-c] Jones and Holl 1886b,p.407 
[Beyrichiidae by Ulrich 1894,p.632; not Placentula 
Lamarck 1822: = Jonesites Coryell 1930,p.29h, 
nomenove] Silurian, Germany. 
PLAGIONEPHRODES [P. uninodosus] Merey 1935a,p.318 [Thlip- 
suridae by Morey; Quasillitidae-Ropolonellinae 
by Henningsmoen 1953,p.257,275] Mississippian of 
Missouri. 
PLATELLA [P. gatunensis] Coryell and Fields 1937,p.3 
[Cytherellidae by C&F] Miocene, Panama. 
PLATYBOLBINA Henningsmoen 1953,pe227,228,268, nomenov. for 
Platychilina Thorslund 1940,p.169,non Koken 1892, 
Genotype: Primitia distans Krause 1889,p.6,pl.l, 
f.3a,b =?Primitia plana Krause, by Henningsmoen 
1954, pe87- Ordovician drift, Germany. 
PLATYCHILELLA [Platychilus ovoides Cooper 1941,p.38,pl.6, 
f.26-27] Cooper 1942,p.777, new name for 
Platychilus Cooper 1941, not Jakolev, 1874 
[Cytherellidae by Cooper; Beyrichiidae by Agnew 
1942,p.760; ?Healdiidae by Henningsmoen 1953, 
p.260] Mississippian of Illinois. 
146 
