306 
PALEONTOLOGY OF NEW YORK. 
the species is exceedingly abundant and very generally distributed, but it is rarer 
toward the east where deposits become more arenaceous. Yet wherever the 
Devonian sandstones are known in Brazil and Bolivia the species abounds. A 
similar form passing current under the name Strophomena or Leptma laticosta, 
Conrad, also occurs in the lower Devonian sandstones (Coblentzian) of Germany. 
An additional species, T. occidens, Hall, has been described from the limestones 
of Hamilton age at Iowa City, Iowa, but its internal characters are not 
known. 
