Helmet types.Two new helmet appeared in I. BC They are related to each other and are usually combined into agenportsky type. Agensky type (17) is reminiscent of bowler hat with fields, while portskogo type with the same "pot" there is a fairly large nazatylnik which is riveted to the helmet (16). Both were wearing helmets naschechniki new type - that was later borrowed by the Romans. Portsky type was a direct prototype Imperial Gallic helmet I in. BC Samples of such helmets
Joys of Flickr: Greek Helmet Evolution & Maps « marshallastor.com
Ancient Rome Military History | ancient roman siege weapons: hebrustan
Celtic Helmets ; Peter Connolly "The helmets 5, 6, and 9 were recovered from senones graves and date from the time before the expulsion of the Celts by the Romans in 282 BC. The cheek pieces, almost all belong to the three-PaB-Type (6)Their similarity with the three-PaB breast plates (S, 24) suggests Samnite origin, the 3rd Century these cheeks flap were simplified to a triangular with three humps"