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Cae Os4 { 
PLATE XXVI 
Unio cristonensis Meek. Triassic. 
Imperfect right valve; part of the outline restored. 
Unio felchit White. Jurassic. 
Right side view; probably a female. 
Dorsal view of the same specimen. 
Left side view of a younger specimen; probably a male. 
Dorsal view of the same specimen. 
Unio toxonotus White. Jurassic. 
Right side view of an adult specimen. 
Dorsal view of the same. 
