The Lower Llandovery form Streptis monilifera altosinuata Holtedahl from Asker, Norway, is redescribed biometrically and a comparison with the Ashgillian 5. monilifera (M'Cov) from Kildare, Ireland, shows the two to be distinct species. The redescription involves the morphological characters of the exterior together with a description of the muscle scars, previously unknown for the genus.