124 HTDROZOIDS AND CORALS. 



Chsetetes, as at present understood, embraces only a few 

 Carboniferous forms. Formerly the name was applied indiffer- 

 ently to a large number of fossils, many of which are now 

 known to have no affinities whatever to the original type. The 

 genus has thus come to include a great many species whose 

 exact zoological relations are not fully understood. Even at 

 the present time there is a considerable diversity of opinion 

 concerning the correct systematic position of the group ; and 

 much remains to be learned of its structural characters. Most 

 of the forms that have been placed under Ohsetetes really be- 

 long to various families of Polyzoans, especially the earlier 

 species, from the Silurian rocks. 



DOUBIFUL SPECIES OF CORALS. 



LithostroUon microstylum White, 1883: Twelfth Ann. Rep. U. S. Geol, 

 and Geog. Sur., p. 150, pi. xl, fig. 7a. 



Too imperfect for description ; and so far as is known no 



specimen has been obtained since the finding of the type, of 



which there is also some doubt as to the locality. Lower 



Carboniferous, Chouteau limestone, Sedalia. 



