Maotianshania cylindrica
Recent phylogenetic analyses place this worm-like animal either within Nematomorpha or Priapulida. It is distinguished from Cricocosmia by it's much more slender appearance, as well as the absence of sclerites on its trunk.
Class: Palaeoscolecida
Family: Maotianshaniidae
Heilinpu Formation
Yunnan Province
International Age: Age 3
Date Collected: No value
Cricocosmia (not Circocosmia, a very common misspelling!) and Maotianshania are really difficult to distinguish - the size is almost the same, but trunk ornamentation seems to be slightly different. I wouldn't dare to distinguish them without a very good microscope.
Lit.: Han, J., Liu, J., Zhang, Z., Zhang, X., and Shu, D. 2007. Trunk ornament on the palaeoscolecid worms Cricocosmia and Tabelliscolex from the Early Cambrian Chengjiang deposits of China. Acta Palaeontologica Polonica 52 (2): 42