PLATE 3. 
Photographs of Triarthrus becki, made by C. E. Beecher. 
Fig. 1. — Specimen 204. See also text fig. 42 and pi. 4, fig. 6. The exopodites and 
endopodites of the first few segments of this specimen are better preserved than those of 
any other revealing them from the dorsal side, x 9.5. 
Fig. 2. — Specimen 220. A large individiial exposed from the lower side. It shows 
well the endopodites and part of the exopodites, and, rather better than any other specimen, 
the endobases of the coxopodites. x 2.4. 
Fig. 3. — Specimen 216. A small entire specimen showing considerable of the detail of 
the appendages of the cephalon, and some of those of the remainder of the body, x 7.4. 
Fig. 4. — Specimen 201. This figure shows the details of the appendages of the left 
side and of the pygidium. Note the plate on the median line back of the pygidium, the 
sockets for spines, and the terminal spines on the anterior endopodites. See also pi. 2, fig. 
1 and pi. 4, figs. 1, 2. X7.1. 
Fig. 5. — Specimen 207. One half of the posterior part of the thorax and pygidium, 
showing exopodites and endopodites as seen from the dorsal side, x 7.6. 
Fig. 6. — Specimen 214. The exopodites have been turned back nearly parallel to the 
axis of the shell. Notice particularly the long flattened seta; and the spinose spatula-shaped 
terminal portion of each shaft. See also pi. 1, fig. 2. x 7. 
