Cyrtoconic nautiloid cephalopods from the British Silurian

Three British Silurian species of the cephalo-pod order Orthocerida are described, two of Cyrtocycloceras and one of Gaspocyrtoceras. Five species described from the order Oncocerida include two of Amphicyrloceras and one each of Cyrtorizoceras, Oonoceras and Bassettoceras, the last genus being new, as are the species Cyrtorizoceras yochelsoni and Amphicyrloceras rickardsi. Their distributions are indicated.