You can tell by the shape and style of the corilites on the skeleton where the polyps sit.....But in Borneman's book most favia do not share polyp walls as opposed to Favites do. This will tell you which species but not subclass like F. matthai ect..... So looking at yours again I would say that it is a favite, chirocato. Where brian29 polyps have there own polyp walls, thus it is or most likely a favia with an unknown subclass.