Middle Cambrian monoplacophorans from Bornholm and Australia, and the systematic position of the bellerophontiform molluscs

Minute Middle Cambrian monoplacophorans originally reported from Australia are redescribed on the basis of material from the Kalby Clay of Bornholm. A recent classification of Bellerophon. Sinuites and related genera as monoplacophorans is discussed and rejected. Members of the group are returned to the Gastropoda on account of their similarity in ornament, musculature and inferred water circulation patterns, with contemporary fossil helically coiled gastropods. Water circulation patterns are deduced in Protowenella flemingi and support the assignment to the Monoplacophora. Kulhyella poulseni n.gen. n.sp. is described.