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Published online by Cambridge University Press: 01 May 2009
Although the process of development of the pygidium in the trilobite has been known since the time of Barrande, its significance does not appear to have been appreciated, and much of the modern speculation on the classification of trilobites is based upon the erroneous idea that those species whose form is most annelidan are most primitive. As a matter of fact, the study of both morphology and ontogeny shows that in this group the large pygidium is primitive and the small one specialized.
page 23 note 1 Lunds Univ. Årsskr., n.f. avd. 2, bd. 15, nr. 3, 1918, pp. 57–67, pl. i, fig. 23.Google Scholar
page 24 note 1 Geol. Mag., Vol. LVI, 1919, p. 109.Google Scholar
page 24 note 2 Amer. Geol., vol. xvi, 1895, p. 175, fig. 6.Google Scholar
