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Show 314 MR. J. Y. JOHNSON ON TRACHICHTHYS DARWINII. [May 22, seventh dorsal spine. They are much longer than the ventral fins, which are inserted under their roots. These fins, which have rounded apices, are supported by a long stout and striated spine and six branching rays. The space between and in front of their roots is flat. The vent is placed a little in advance of the anal fin, about three-fourths of the total length behind the snout. The trapezoidal anal fin commences under the seventh soft ray of the dorsal fin, and terminates at some distance from the base of the caudal fin, a little behind the end of the dorsal. The first of its three stout spines is very short; and the third, though much longer than the second, is only half as long as the soft portion of the fin is high. The lobes of the deeply forked caudal fin are rounded at the tips, and the membrane between the rays is clothed with rows of small scales. At both the upper and under edges of the tail, and supplementary to the caudal fin, is a series of six glassy spines, which become gradually larger backwards. The spines of the fins are striate but not roughened, whilst the exposed sides of the rays are strongly echinulate. The lateral line is a slightly elevated and oblique ridge on the upper part of the body, not following the curve of the back. It is formed of twenty-seven perforated and rather distant scales, which are somewhat larger than those clothing the body. Only a single specimen of this interesting addition to the marine fauna of Madeira has been hitherto obtained. It was taken in the month of April of the present year ; and, from the protruded stomach and inflated membranes about the eyes, it may be inferred that it came from a great depth. I have named it in honour of that accomplished man of science, Charles Darwin, Esq., to whom naturalists are greatly indebted, amongst many other labours, for an excellent monograph on the Cirripedia. The fishermen from whom I procured the specimen stated that they had never previously seen anything similar; the name of " Serra do alto," or Sawfish, alluding to the ventral keel, was therefore merely an impromptu appellation. From Hoplostethus mediterraneus, C. & V. (of which I have obtained a few specimens at Madeira), it is distinguished generically by the possession of vomerine teeth. Even if it were congeneric with that fish (and some ichthyologists may think that Hoplostethus should not be separated from Trachichthys), several well-marked differences would point it out as a distinct species : e.g., 1, the possession of eight spines and fourteen rays in the dorsal fin in place of six spines and thirteen rays, and of three spines and twelve rays in the anal fin in place of three spines and nine or ten rays; 2, the scaly cheeks; 3, the absence of a series of oblong cells near the posterior border of the preopercle; 4, the exposure of the whole branchiostegal membrane, which in Hoplostethus is entirely concealed by the gill-covers ; 5, the shortness of the pectoral fins, which do not reach, as in Hoplostethus, to the vent. With the two known species (both of them Australian) of the genus Trachichthys it agrees in having teeth on the vomer; but |