PATAGONIAN EXPEDITIONS : PALEONTOLOGY. 
EXPLANATION OF PLATE XX. 
Fig. i. Ostrea patagonica d’Orb. ........ 
From beds, unconformably overlying Patagonian beds (?Tehnelche 
formation); Darwin Station, San Julian. 
i a. Lower valve of an elongated individual. 
ib. Lower valve of a more elongate individual, showing distinct 
folds. 
ic. Upper valve of another elongate individual. 
id. Upper valve of a very broad individual, showing a muscular 
scar of the character of that of O. pyr other iorum v. Ih. 
All the figures are natural size. 
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