 A few months later in 2006 Butterfield returned to the fray.As in 1990, he argued that "Wiwaxia"’s sclerites were internally much more like the bristles of polychaete annelids such as "Canadia" than like any forerunner of molluscan shell plates; since a 2005 paper had downplayed this argument with the comment that similar bristles also appear in molluscs and brachiopods, he pointed out that modified bristles appear as a covering over the back only in polychaetes and hence "Wiwaxia"s sclerites should indeed be regarded as like polychaetes' bristles.In addition he argued that "Odontogriphus"’ shedding and replacement of tooth-rows, the rows' staying in the same relative positions when isolated and the evidence that "Odontogriphus" sometimes swallowed discarded tooth-rows did not prove that "Odontogriphus" was an evolutionary "aunt" of molluscs, since eunicid polychaetes also molt and replace their feeding apparatus (which sometimes resembles a radula), and sometimes eat the discarded material.