In this way the anterior exopodites have been thrust under the glabella and all the appendages have been moved to the right of their original position. The anterior exopodite is very poorly shown, but seems to be articulated in front of the eye. The posterior exopodites are very similar to those on the thorax. The distal lobe is shown only by the second from the last. It has the same form as the distal lobes on the thoracic exopodites, and like them has much finer setæ than the main lobe, but it does not stand at so great an angle with the axis of the main lobe, nor yet is it so straight as shown in Walcott's figure. _Measurements:_ The specimen is about 72 mm. long and 54 mm. wide at the genal angles. The pygidium is 22 mm. long and 37 mm. wide. The doublure is 1.5 mm. wide. The exopodite of the third thoracic segment is 19.5 mm. long. The pleural lobe at this point is 13 mm. wide without the spines and 18.5 mm. wide with them. The third exopodite of the cephalon was apparently about 15 mm. long when complete. Specimen No. 65515. Illustrated: Walcott, Smithson. Misc. Coll., vol. 67, 1918, pl. 20, figs. 3, 4. This is a small piece of the axial portion of a badly crushed Neolenus, showing appendages on the left side as viewed from above. On the posterior half there are three large appendages which have the exact form of the exopodites of other specimens. There is a broad, oval, proximal lobe and a distal one at an angle with it. The proximal part of the shaft has fine setæ or the bases of them, and the distal lobe faint traces of much finer ones. The form, and the setæ so far as they are preserved, are exactly like those of the exopodites on the specimens previously described. (See fig. 4, page 26.) Beneath them there are slender, poorly preserved endopodites. In front of the exopodites and endopodites lie a series of structures which Walcott has called exites, but for which I can see another explanation. Walcott has shown them as four broad rounded lobes, but his figure must be looked upon as a drawing and not as a photograph, for it has been very much retouched. For convenience of discussion, these lobes may be called Nos. 1, 2, 3, and 4, the last being the posterior one (fig. 5). This lobe is best shown on the matrix, where the anterior end is seen to be margined by stout spines, while the posterior end lies over the endopodite and under the exopodite behind it. No. 3 is sunk below the level of the others, and only a part of it has been uncovered. Its margin bears strong spines of different sizes. Its full shape can not be made out, but it has neither the shape nor the form of spines shown in figure 3, plate 20 (1918). Lobes 2 and 1 and another lobe in front of 1 seem to form a continuous series and to be part of a single appendage. They are all in one plane, arc so continuous that the joints between them can be made out with difficulty and if they do belong together, can easily be explained.