PLATE 4.
Photographs of Triarthrus becki, made by C. E. Beecher.
Fig. 1. Specimen 201. Another photograph, similar to [fig. 4, pl. 3], but showing more clearly some details of spines on the endopodites. × 12.66.
Fig. 2. Specimen 201. Three appendages on the right side of the thorax. See also [pl. 2, fig. 1] and [pl. 3, fig. 4]. × 12.66.
Fig. 3. Specimen 223. A small crushed specimen which nevertheless shows well the appendages of the right side of the thorax, developed from the ventral side. Note coxopodites, exopodites, and endopodites, and that all appendages are moved equally laterally from their original position. × 11.4.
Fig. 4. Specimen 219. Another photograph, with different lighting, of the individual shown in [pl. 2, fig. 6]. This print brings out better the coxopodites and the folds of the ventral membrane. × 3.23.
Fig. 5. Specimen 222. This specimen is interesting, because it shows the endopodites in what is probably their natural position, that is, in a plane nearly vertical to the plane of the body, instead of being flattened down, as is usually the case. The appendages under the pygidium are unusually well preserved. × 12.
Fig. 6. Specimen 204. Photograph of the entire specimen of which a part is shown in text [fig. 42] and [pl. 3, fig. 1]. × 4.5.