0. eras so lame Hat a -32- 
forms of the species; and differs from the forms with three more 
or less incomplete septal cycles in the greater thickness of the 
inner part of the septal laminae, the broad exothecal cells, and 
in the disposition of the tertiary septa to join the secondary* 
Prom the lithological character of the specimen thus de- 
scribed (Coll. Geol. Soc.), it is either from the Chert -format ion 
of Antigua or from the lower part of the Marl*" 
