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PALEONTOLOGY 



F IG . 49.WHORL-SHAPE IN AMMONOIDEA. 



All except e, g, and h are apertural views, a, Microderoccras, lat-umbili- 

 cate, rotifortn, whorl-section quadrate, b, Dactylioceras. lat-umbili- 

 cate, planulate, whorl-section rounded, c, Chamousettia, angust- 



