Note 24 — Blind Trilobites.
Reading edition
Fossiler fra Öxna og Klettna, Geol. För. Förhandl. 1875, p. 572, pl. 25, fig. I-X.
[25] Foremost among these stands Matthew in »Illustrations of the Fauna of St. John» IV, where he, p. 143, pl. II figs. 1 f. etc., describes a few stages very like those given by Brögger, so the glabella as an unsegmented, narrow ridge etc.
[26] A deviating form of the ridges is shown by »Liostracus» tener Hartt, Acad. Geol. 2d Ed. p. 652 (see also Matthew Illustrations of the Fauna of St. John [1887] p. 132 p. 1 f. 3 a-3 c). Beside the usual facial ridge there is a second pair of ridges between the first and the glabella, arching in an opposite direction. See also Walcott, Bulletin U. S. Geol. Survey, N:o 10, 1884 pl. V, figs 6, 6 a, 6 b, new figures and copy of Hartt's description.