Illustrated: Amer. Jour. Sci., vol. 13, 1902, pl. 5, figs. 2, 3 (photographs). This is a small imperfect specimen, developed from the ventral side. It retains the best preserved metastoma in the collection, but was used by Professor Beecher especially to illustrate the convergent ridges on the inside of the ventral membrane in the axial region of the thorax. These ridges are very low, and on each segment of the thorax there is a central one, outside of which is a pair which are convergent forward, making angles of 35 to 45 with the axis. The metastoma is shaped much like the hypostoma of an _Illænus_. It is convex, nearly semicircular, with the straight side forward, and there is a continuous raised border around the curved sides and back. This border is separated from the central convex body by a deep linear depression. The hypostoma is also rather well preserved and has a narrow, slightly elevated border at the sides and back. _Measurements:_ The incomplete specimen, from which only a very small portion of the length is missing, is 9 mm. long. The metastoma is 0.45 mm. long and 0.58 mm. wide. Specimen No. 214 (pl. 1, fig. 2; pl. 3, fig. 6). This is a large specimen, developed from the ventral side. It shows the antennules and some other appendages of the head, but derives its special interest from the excellent preservation of a few of the exopodites, which are turned back parallel to the axis of the body and lie within the axial lobe. The shaft of the exopodite is made up of numerous short segments which at their anterior outer angles are produced into spines, and which also bear movable spines along the anterior border. As shown in several other specimens, the exopodite ends in a more or less long spoon-shaped segment bearing on its lower surface a broad groove. No setæ appear to be attached to this, but both anterior and posterior margins bear numerous small, apparently movable spines. From the groove along the ventral side of the remainder of the exopodite arise numerous long slender filaments which become progressively shorter toward the tip. This specimen shows that they are not cylindrical, but are flattened along opposite faces, at least at their distal ends. While no connection can be seen between adjacent setæ, they seem to stay together like the barbs on a feather. _Measurements:_ Length, 33 mm., width at back of cephalon, 16 mm.; from front of cephalon to back of hypostoma, 6 mm. Specimen No. 219 (pl. 2, fig. 6; pl. 4, fig. 4). Illustrated: Amer. Jour. Sci., vol. 13, 1902, pl. 4, fig. 1, pl. 5, fig. 4 (photograph and drawing).