_Cirri_ not much elongated; first pair placed not quite close to the second; five posterior cirri nearly equal in length; pedicels long, with irregularly scattered spines,--those on the pedicel of the first cirrus beautifully and conspicuously feathered. The segments of the three posterior pair are _not_ very short or broad; very slightly protuberant, each with a long transverse, crescentic, narrow brush of bristles, which stand two or three deep in the middle, but on the sides are single: dorsal tufts long, and in the upper segments the spines are thick and claw-like. This structure is common to all the cirri. First cirrus with the rami unequal in length by two segments; from the shortness of the pedicel, this cirrus is much shorter than the second, but its rami are about two thirds of the length of those of the second cirrus. Second cirrus (and in a less degree the third cirrus), with the anterior ramus a shade broader than the posterior ramus, and rather more thickly covered with spines than are the three posterior cirri. Fifteen segments in the sixth cirrus; nine in the longer ramus of the first cirrus. _Caudal Appendages_, rather longer than the pedicels of the sixth cirrus, composed of seven cylindrical, tapering segments, each with a circle of very fine bristles on its summit. The acoustic (?) sacks are situated some way below the basal articulations of the first cirrus. 2. ALEPAS PARASITA. ALEPAS PARASITA. _Sander Rang._ Man. des Mollusq., p. 364, Pl. viii, fig. 5, 1829.[44] ANATIFA UNIVALVIS. _Quoy_ et _Gaimard_. Annales des Sciences, Nat., tom. x, p. 234, 1827, Pl. vii, fig. 8. ---- PARASITA. _Quoy_ et _Gaimard_. Voyage de l’Astrolabe, Pl. xciii, 1834. TRITON (ALEPAS) FASCICULATUS. _Lesson._ Voyage de la Coquille. Mollusc. Pl. xvi, fig. 6, tom. ii, part I, 1830, p. 442. [44] M. Sander Rang rejects the specific name “_univalvis_,” as signifying a generic character, and he has been followed in this by MM. Quoy and Gaimard themselves. This, according to the Rules of the British Association, would hardly have been a sufficient reason, but it appears that _A. parasita_, like _A. minuta_, has a pair of horny scuta or valves; and, therefore, the name _univalvis_ is too obviously false to be retained. With respect to the generic name Triton, I fully believe that it was applied by Linnæus to the cast-off exuviæ of sessile Cirripedes. _A. aperturâ non prominente, capituli longitudinis 2/3 æquante: scutis corneis: longitudine totâ ad 2 uncias._ Orifice not protuberant, equalling two thirds of the length of the capitulum: scuta horny. Total length two inches. Animal unknown. Parasitic on Medusæ, Mediterranean and Atlantic Oceans: south shore of England(?)[45]