Published online by Cambridge University Press: 01 June 2000
The occurrence of developmental abnormalities in two ovoviviparous littorinids (Littorina neglecta and a barnacle-dwelling form of L. saxatilis) inhabiting the barnacle zone at Peak Steel, Ravenscar on the north-east coast of England was investigated. In general developmental abnormalities appeared to be a rare occurrence in both taxa. However, L. neglecta was found to have a significantly greater proportion of deformed embryos in their brood pouches than L. saxatilis B (Figure 1). A distinct seasonal variation in the number of developmental abnormalities was observed in L. neglecta, and it is suggested this is a result of broods developing outside of the main reproductive season being more prone to deformity.