Coelosphaeridium (Chlorophyta Dasycladaceae) from the Caradocian beds of N. Wales

During my study of Ordovician fossils in British Museums, I especially noticed some specimens which appeared to belong to Coelosphaeridium, a genus not hitherto reported from Great Britain They belong to the British Museum (Natural History), and Dr. K. P. Oakley kindly arranged a loan, so that I have been able to study the specimens more closely.