Note 200 — Chapter VIII · TRILOBITA
Reading edition
“A Natural Classification of Trilobites,” Amer. Jour. Sci. (4), iii., 1897, pp. 89–106, 181–207. Reprinted in Beecher’s Studies in Evolution, 1901, p. 109. A classification based on the character of the pygidium has been proposed by Gürich, Centralbl. für Min. Geol. u. Pal. 1907, p. 129. A classification based on the minute structure of the test has been given by Lorenz, Zeitschr. d. deutsch. geol. Gesellsch. lviii., 1906, p. 56.