84 



Table showlnff appi'oxbnakly tlie kvmon distribution of the chief groups of Bro.chtopoda in 



geological time — Coutinued. 



Camarella, Billings (t-p. ) 

 Anantropliia, Hnll . 

 Amplngenia, Hall . 

 Gjpidula, HalJ . . . 

 Fentatr>,ercUa^ Hall . . 

 Stcnoseldsma, (Conrad). 

 Syntn''.lamna, Meek. 



ItHYSCHONELUDjB . . 



? Eichwaldia, Billings . 

 Eaionia, Hall. . . . 

 Triples-ia, Hall. . . . 

 AntirJiyncJioneHa, Quenstedt 

 Camarella, Billings (pars) 

 Iltiynclionclla,, Fischer . 

 Jjciorhynehus, Hall, not End 

 lUiynckopora, King . 

 J)imereUa,Zittel. . 

 Jihynchoncllina, Gemellaro, 

 Acanthothyris, D'Orbigny 

 Hemiikyris, Broun . . 



ATRTPIDjE 



Zygospira, Hall . . . 

 Coelospira, Hall . . . 

 Atrypa, Dalman . . . 

 Anoplotheca, Sandbergcr 

 Davidsonia, Bouch . 

 ? Koninckina, Suos.°. . 



SPIEIFERIUiB .... 



.' Skenidium, Hall . . 



Meristina, Hall (?) . . 



Merutella, Hall, 18G1. . 



Merista, Suess. . . . 



Atfiyris, M'Coy . . . 



Spiri/er, Sowerby. . . 



Cyrtia, Dalman . . . 



