Surirella librile. Lectotype: Drawing BHUPM 1151. A Girdle view representing the lectotype (corresponding to preparation BHUPM 540177-3 in 3D) B Valvar view representing the lectotype; Ehrenberg indicated two views of one cell with dots between the undulated girdle view in A and the valvar view in B. C Corresponding preparation BHUPM 540177-4 D Corresponding preparation BHUPM 540177-3 E Documentation of Ehrenberg’s observations in 1826 F Small cells in girdle view not correponding to the published protologue. Scale bar for C–D = 10 µm.