[855] Feistmantel (73), p. 491, Pl. XXIV. figs. 3 and 4.
[856] Vide specimens 20 A, 20 B, 24 in the Williamson Collection.
[857] Stur (75), p. 17.
[858] Rothpletz (80), p. 8.
[859] Weiss (84), p. 56.
[860] Scheuchzer (1723), p. 19, Pl. IV. fig. 1.
[861] Schlotheim (04), Pl. II. fig. 24, p. 57.
[862] Sternberg (25), p. 32.
[863] Brongniart (22), Pl. XIII. fig. 8, p. 234.
[864] Ibid. (28), p. 68.