1871.—On the structure of trilobites. Geol. Mag., dec. 1, vol. 8, pp. 289-294, pl. 8.
1884.—Notes on the appendages of trilobites. Geol. Mag., dec. 3, vol. 1, pp. 162-165, 2 text figs.
1895.—Some points in the life history of the Crustacea in early Palæozoic times. Quart. Jour. Geol. Soc., London, vol. 51, pp. lxx-lxxxviii, 1 pl.
PLATE 1.
Photographs of Triarthrus becki, made by C. E. Beecher.
Fig. 1. Specimen 213. The dorsal test has been removed from the glabella, revealing the outline of the posterior end of the hypostoma, the proximal ends of the antennules, the gnathites, and incomplete endopodites of some appendages, × 5.43.
Fig. 2. Specimen 214. The head of a complete large specimen. Part of the thorax is shown on [pl. 3, fig. 6]. Note especially the form of the segments of the endopodites and of the anterior coxopodite on the right side, × 7.33.
Fig. 3. Specimen 217. This specimen shows better than any other the form of the gnathites of the cephalon. Note also the setæ of the exopodites under the cheek at the right. The appearance of a hook on the posterior gnathite on the right may be accidental, but it does not show broken edges, × 6.85.