The Lorica armor tells us this is the classic Caesarian or Augustan legion that you see in movies all the time. Though the legions did well at this time, they still suffered two of their five worst defeats at about this time. Click for more on that. Painting by Chris Collingwood.
The Roman army of the mid-Republic was also known as the "manipular army" or the "Polybian army" after the Greek historian Polybius, who provides the most detailed extant description of this phase. The Roman army started to have a full time army of 150'000 at all times and 3/4 of the rest where levied.