EXPLANATION TO PT,ATF, XVI. 



Fa:. 1. fifrliitfiri'Hn luiiin ;/' Nutting. Part of )>rancli (enlarged). 



1'. Si rliiliin-llii i/riiii-ii/iitti IlinckH (enlurged). (After Ilincks.) 



:;. Hn-itil<iirl/<i jiiitiHjiiitii'ii (d'C)rbigny) (enlarged). (After d'Orbigny.) 



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