Fic. 
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FIG. 
1. 
we 
3 
4, 
PLATE 20. 
OSTREA WYOMINGENSIS .. -. -- ----2--- e220 + eee cee cece oe ence cree see cee 
a. Lower valve; interior view ; natural size. 
b. Upper valve ; exterior view; natural size. 
c. Interior view of the same, showing hinge, pedal museular scar, 
and area. 
AXINZZA HOLMESIANA .-.-.-------------- sie slel Selec ereeeiseee eee sya 
a. Exterior view; natural size. 
b. Interior view of the same, showing part of hinge and area. 
ODONTOBASIS BUCCINOIDES ....-- Eisieia Hiaiavap le Sean eee teres See aes 
a. Side view of an imperfeet example; natural size. 
b. Similar view of another example, showing a variation of form. 
MIntANTA? SINSCULPTAG dsb a)e cece ee cece cesar ee eee eee 
a. Side view of a fragment, which is one of Mr. Meek’s types; natural 
size. 
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