Studies on Graptolites II. On the development and structure of graptolite genus Gymnograptus Bulman

This paper describes the astogeny and structure of Gymnograptus linnarssoni (Moberg) and G. retioloides (Wiman) and also the structure of Gymnograptus sp. The material has been etched from erratic boulders of Scandinavian origin, which are of Middle Ordovician age. The systematic position of the genus Gymnograptus is discussed.