open strips 72 in line with the lands 62 on roll 20 the operation of the grooved roll 25 is similar to that of roll 20 but complementary thereto by reason of the axially offset relation of the grooves and lands thereon with respect to those on roll 20 thus roll 25 will similarly create laterally spaced strips of thickened pulp on the run of the wire traveling to the couch roll 22 but these strips will be so aligned with the relatively bare strips 72 on the run of wire approaching from roll 20 to provide an essentially continuous mat of pulp across the run of the wire from roll 25 to roll 22 as illustrated at 73 in fig2 at the station of roll 25 the strips of pulp already on the wire which pass between the wire and the lands 62 on roll 25 will be further dewatered and compressed by the combination of centrifugal force and the pressure generated by wire tension if there is any tendency of these compressed strips to transfer from the wire to the lands 62 on roll 25 this can be counteracted by a doctor 75 preferably of the same non contacting type as doctor blade 55 which in combination with centrifugal force will assure that all pulp thickened by passage with the wire around roll 25 will continue to travel on the wire.