The paper deals with a biometrical analysis of forty-one specimens of the Gwyniad, Coregonus clupeoides pennantii (Cuv. et Val.) of Bala Lake, (Llyn Tegid) North Wales. Tho Gwyniad shows the greatest relationship to the continental coregonids Coregonus lavaretus. It is proposed that the taxonomy of the British whitefishes be revised and that the Gwyniad be classified as Coregonus lavaretus pennantii (Cuv. et Val.). Similarly, it is proposed that the Powan of Loch Lomond be classified as Coregonus lavaretus clupeoides Lacépède. The classification of the Schelly from the English Lake District needs further investigation.