Mr. H. D. S. Goodsii* on nmv species of Crustaceans. 325 XXXVI. — On several nciv species of Crustaceans allied to Saphi-rina. By Harry D. S. Goodsir, M.W.S., late Conservator of the Museum of the Roy. Coll. Surg. Edinburgh^ Assist. Surgeon in H.M. Ai'ctic Exploring Ship Erebus. One of the most striking features in the structure of this pecu-liar form of Crustacean is the double eye in a single dark spot. The antennre are similar in form to those of the Isopoda, being either filiform or almost truncate^ the general form of these or-gans in the Isopoda, and by no means like those of the Monoculi, which are setaceous and very often dilated in the middle. As in the Isopoda, they are short, being generally about as long as one-half of the breadth of the body. The animals here referred to have a projection from the me-sial line of the carapace, analogous to the rostrum, generally found in the Monoculi, and in the extremity of this rostrum the eye is generally situated. The first segment of the body is in all cases longer than the remaining segments combined, and in some instances the lateral edge is curved inwards and downwards, so as to give it the ap-pearance and form of a carapace. The remaining segments of the body are small, gradually decreasing from the second to the terminal. In several species the terminal abdominal segment is provided with a jointed pedicle on each side, which is armed at the extre-mity with spines, and in some species this structure is exactly similar to Monoculus. The anterior extremities are very short, so much so as not to be seen extending beyond the edge of the body ; generally however one or more joints of the last pair of legs are seen posteriorly. The most striking character in this order of animals is the double extremities, a character common to the Stomapoda and Monoculi as well as this form of Crustaceans. As in Stomapoda the two teiTninal filaments arise from one common pedicle, the external one being much longer than the internal ; the former also is chelate and three-jointed, the latter four-jointed. The number of joints however in these legs varies. The legs arising from the carajiace (first thoracic legs) are not double, or if so, one of the terminal filaments is obsolete. These animals are very active in their habits, and swim about in company with the other forms of the family Pontia. Body depressed as in the Isopoda ; posterior thoracic legs double. Sterope oralis. Plate XI. fig. 11. Rostrum not prominent; antennae unarmed, three-or four-
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