 Most fossils of Wiwaxia are just a jumble of armor plates and spines , but after examining dozens of them Conway Morris reconstructed them as slug @-@ like animals covered in rows of overlapping armor plates , with two rows of longer spines projecting upwards . Since 1990 there has been an intense debate about whether Wiwaxia was more closely related to molluscs or to polychaete annelids . Supporters of a close relationship with molluscs maintained that a pair of bars , running across the mouth and armed with backward @-@ pointing teeth , were a rudimentary form of the radula , the toothed tongue that molluscs use to scrape up food and convey it back to the throat . Nicholas Butterfield , the one academic who has so far published articles placing Wiwaxia closer to polychaetes , stated that Wiwaxia ′ s two @-@ row feeding apparatus could not have performed the sophisticated functions of the multi @-@ row , conveyor @-@ belt radula , suggesting instead that Wiwaxia ′ s apparatus was like the side @-@ by @-@ side pair of toothed bars found in some polychaetes . Later he found some fragmentary fossils , 5 to 10 million years before the Burgess Shale , that he regarded as a much more convincing early radula . Butterfield has also described Wiwaxia ′ s armor plates and spines as similar in internal structure to the chetae ( " hairs " ) of polychaetes . Supporters of the link with molluscs have stated that Wiwaxia shows no signs of segmentation , appendages in front of the mouth , or " legs — – all of which are typical polychaete features . One writer adopted a neutral position , saying he saw no strong grounds for classifying Wiwaxia as a proto @-@ annelid or a proto @-@ mollusc , although he thought the objections against classification as a proto @-@ annelid were the stronger . 
