SYSTEMATIC INDEX 
OF THE 
FAMILIES, GENERA, AND SUBGENERA. 
[Those Genera marked with an asterisk are not in the Collection, but they 
have been specially mentioned or else described in the text.] 
Page 
Suborder NAUTILOIDEA 1 
Eamily OETHOCEEATID^ 1 
Orthoceras 1 
Family EXDOCEEATID.E 129 
Eudoceras 129 
Piloceras 157 
Family ACTIA'OCEEATID^ 164 
Actinoceras 164 
Discosorus 194 
Huronia 199 
Sactoceras 207 
Family GOMPHOCEEATIDiE 211 
Gomphoceras 211 
Tetrameroceras 235 
Hexameroceras 242 
^Xlesoceras 244 
^Trimeroceras 245 
^Pentameroceras 245 
'*'^Septameroceras 246 
