PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 619 
known. Raymond suggests that “the original specimen may have been a young 
Camarotoechia plena, a young Camarotoechia pristina, or a broken and exfoliated 
Hebertella.” 
Although Hall and Clarke named A. dubia as type of their genus, they realized 
that the species on which it was based was poorly described because they did not 
use the type specimens to derive their generic diagnosis. Instead they used speci- 
mens from “the gorge of the Kentucky River, at High Bridge, Kentucky” which 
they erroneously identified as Hall’s “Atrypa” dubia. This procedure of course, 
under the rules, has no bearing on the validity of their selection of A. dubia as 
the type of the genus. 
To add still further to the confusion Hall and Clarke failed to refigure Atrypa 
dubia and also published no figures of the Kentucky specimens from which they 
derived their generic description. Instead they illustrated a Silurian species 
called Protorhyncha aequiradiata Hall which actually shows the chief generic 
characteristics of Rhynchotrema or Camarotoechia (pl. 56, fig. 8). The generic 
diagnosis and the species on which Protorhyncha is based thus prove to be vague 
and poorly founded, and this is true also of the species proposed by Raymond 
to serve as neotype. 
In his discussion of Protorhyncha Raymond suggests that, inasmuch as the 
type species P. dubia is unrecognizable, the species from which Hall and Clarke 
derived their generic diagnosis be used as the type of the genus. This is the 
species identified by Ulrich as Rhynchonella ridleyana (Safford). The name 
Rhynchonella ridleyana was first used by Safford (1869, p. 287) without defini- 
tion or other designation than to list it as having been taken from the Pierce and 
Ridley limestones. When Hall and Clarke prepared their generic description of 
Protorhyncha, they stated that their information was derived from specimens 
coming from High Bridge, Ky., but failed to use any specific name in connec- 
tion with them, and it is therefore at least implied that they identified their speci- 
mens with P. dubia rather than P. ridleyana. In the Columbia Folio Ulrich 
(1903) uses the new combination Protorhyncha ridleyana for the first time in a 
list of characteristic fossils of the Ridley limestone but failed to furnish a defi- 
nition of the species. This combination has been in use for some time not only 
for specimens from the Ridley limestone of central Tennessee but also for speci- 
mens from High Bridge, Ky. Although the name has long been in use, no defini- 
tion of it has ever been prepared. 
From the above remarks it will be seen that the definition of Protorhyncha 
is based on misidentified fossils and that the named type is unrecognizable. Fur- 
thermore, the attempt to establish P. ridleyana as type of the genus fails because 
that species is still a nomen nudum and without validity. The name Protorhyncha 
thus proves to be one of very dubious value, and it seems best to leave it with 
the unrecognizable specimens for which it was proposed and to supply a new 
name for the splendid material of several species that had hitherto been placed 
in Protorhyncha. 
Ancistrorhyncha at present has no close relatives to which it may be compared. 
It is distinctly not the first of the rhynchonellids but a fairly highly specialized 
