Mesoceras

Mesoceras is a mid Silurian discosorid from central Europe named by Barrande in 1877, with a short, anteriorly contracted body chamber and an aperture that is a long transverse slit.. The cross section is slightly oval with the dorso-ventral dimension slightly less than the lateral. Sutures are straight and transverse, the siphuncle is subcentral.
The relationship of Mesoceras to the other discosorids is unclear but it is most likely derived from the Mandeloceratidae, perhaps from ''Ovacerina''