IOWA ACADEMY OF SCIENCE Voi,. XXIX, 1922 
Valves smooth except as noted; partly exfoliated shells under 
a strong lens show fine crowded radial lines and in some cases 
equally fine concentric lines. Internally the critical features of the 
genus are brought out in the series of sections here illustrated. 
The species differs from P. altus in its generally coarser, broader, 
and less acuminate appearance; in the variable number of plica- 
tions on the fold and sinus ; and in the shorter and more rectangu- 
lar deflected extension of the pedicle valve; and in having on the 
whole less angular plications. 
Position and Localities : Limited to the State Quarry limestone 
at the old State Quarry near North Liberty and at various small 
outcrops to the west and south of Solon in Johnson county, Iowa. 
Figs. 1-16. 
1-4. 
5-8. 
9-12. 
13, 16. 
14,15. 
Figs. 17-32. 
17-20. 
21-24. 
25-28. 
29, 32. 
30, 31. 
PLATE I 
Pugnoides altus (Calvin) 
Brachial view of four typical specimens ; number 1 has four 
plications on the fold, three is the usual number. 
Pedicle view of four specimens. Note the short plications 
on the lateral slopes. 
Four specimens showing the tapering, linguiform extension 
of the pedicle valve. 
Two specimens viewed from the side showing the trigonal 
shape and the incurved beaks. 
Two examples viewed posteriorly; note the sharply angular 
plications on anterior part of the fold. 
Pugnoides solon. Thomas and Stainbrook. 
Brachial view of four specimens showing the shape of the 
shell and the stout, short plications. 
Pedicle view of four specimens. 
Anterior view of four individuals showing the thickness of 
the shell, the zigzag front margin, and the variable number 
of plications on the fold and sinus. Number 28 has but one 
in the sinus. 
Lateral view of two specimens showing the plications of 
the lateral slopes. 
Posterior view of two examples showing the thickness of 
the shell, the plications on the fold, and the elevated ends 
of the lateral plications of the pedicle valve. 
