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Show 138 MR. CYRIL CROSSLAND ON THE [June 16, of the body the feet are provided with this and one aciculum only. The ordinary setae project considerably, especially in the anterior-feet. Here they are arranged in two distinct bundles of simple capillaries dorsally and compound ventrally, with a set of shorter and stouter compound seta? between the two. Posteriorly this arrangement is less definite, the bundles running into one another. The long capillaries are as usual slightly bent, smooth, and end in a very delicate point. Long and slender comb-setae occur among the more ventral capillaries (PI. X I V . fig. 5) of the posterior segments, the teeth of which, except the two outermost, are hardly to be made out even by the ^-in. objective. The articulated pieces of the compound seta? are of the knife-shape. Their proportions are shown in PL XIV. fig. 5. Text-fig. 12. Marphysa macintosh!. Mandibular jaw-plates, X 45. The gills begin from seg. 32 to 54, attaining their full size more gradually in the former case. Their greatest number of branches may be four, five or, six, of moderate length, i. e. they can be nearly made to meet over the back. Their arrangement is bushy rather than comb-like (PI. XIV. fig. 6). As the gills are present up to the ends of all three fragments, it is most probable that they extend to near the anus. All the other species of Marphysa in which an undivided prostomium is met with are characterised by the possession of few, and those very large gills. The present species therefore occupies a conspicuous position in the genus, as indicated in the above table. The shortness, slenderness, and insertion of the tentacles, the rudimentary condition of the eyes, and the articulation of the ventral cirri are also prominent specific characters. |