The Longacre design without stars on the obverse combined with the 'Standard Silver' reverse of 1870. This was apparently implemented by William Barber as Longacre died in 1869.
These were sold as part of complete sets from the half dime to the silver dollar. To view the set, click here.
In addition to the illustrated silver example, for which a half a dozen are known, these were also struck in copper J1075/P1211 with fewer than a dozen known and aluminum J1076/P1212 with only the Queller and Newman-Simpson examples comfirmed.