BRACHIOPODA. 
215 
There is considerable variation in exterior among the Camarophorias. C. 
Schlotheimi is a triangular or deltoidal shell with the plication clearly developed 
on fold and sinus, but obscure on the lateral slopes. The greater number of 
the European and Indian Carboniferous and Permian species have a similar 
exterior. In C. Schlotheimi, von Buch, and C. Humhletonensis, Howse, the margins 
of the shell are, normally, expanded as in some Devonian forms of Airypa reti¬ 
cularis. Camarophoria suhtrigona, Meek and Worthen, C. isorhyncha, McCoy, are 
large subcuboidal species, while C. ringens, Swallow, C. caput-testudinis, White, 
and C. subcuneata, Hall, are acutely triangular in outline, with broad, concave 
cardinal slopes. The species of both the latter groups are strongly plicated 
throughout, while in C. ringens the surface also bears a fine radiate linea- 
tion. 
The Camarophoria (Pentamerus) lenticularis, White and Whitfield, from the 
Yellow sandstones beneath the Burlington limestone, at Burlington, Iowa, is a 
shell widely different from all the foregoing in external features. The valves 
are biconvex and their outline subcircular ; it has no fold and sinus and no 
plications, the surface being smooth and regularly arched. To associate it 
generically with the plicate trihedral Camarophorias requires an effort of the 
imagination. At the same time its internal characters are normal for Camako- 
PHORiA, except that the broad, spatuliform spondylium rests upon the valve 
for most of its length, the median septum penetrating it and projecting 
above it into the interior cavity of the shell. It is proposed to signalize 
these differences, and thus to render the association constituting Camaro¬ 
phoria the more homogeneous, by giving this species the subgeneric designa¬ 
tion, Camarophorella. 
