In 1848, under the name Agelacrinites Buchianus, Edward Forbes introduced to science “one of the most remarkable Cystideans as yet discovered in British strata.” His description and figures, published in his memoir “On the Cystideæ of the Silurian rocks of the British Islands” (Mem. Geol. Surv. Gt. Brit., II, pt. ii; see pp. 519–523, and pl. xxiii), have not proved fully intelligible to subsequent workers, even to those who have had the fossil before them. Unfortunately J. W. Salter, in his “Appendix. On the Fossils of North Wales,” to “The Geology of North Wales” by A.C. Ramsay (Mem. Geol. Surv. Gt. Brit., III, 1st ed., 1866), criticised a little, but illuminated less; while the same Appendix in the second edition, 1881, though “greatly enlarged and partly rearranged by Robert Etheridge, F.R.S.,” merely introduced verbal alterations into Salter's account.