ICHTHYOLOGY.

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is unnamed, is black above and of a lighter colour beneath. D. 14, 14 ■A. 3, 12. 15".

Gerres equula,\&. (ib.) 1). 9, 11; A. 3, 8. Greenish blue.

Ditrema, n. g. id. (ib.), in the family of the Msenides, is distinguished bya very low dorsal fin and an opening behind the anus. The species has D.10, 22 ; A. 3. 27.

He has instituted a new genus Chcetopterus, which, in habit, would appearvery nearly to approach Aphareus; but it is furnished with vomeral teethand four rays in the branehiostegous membrane. D. 10, 10; A. 3, 8.

In the family of the Squamipennes several new generaand species have been instituted.

Cheetodon modesius, Schlegel (Fauna Japonica, p, 80.) resembles Gh.melanopus, Reinwardt; it is milk-white, with four light brown bands, a blackspot on the commencement of the soft part of the dorsal fin. D. 11, 21;A. 3, 20.— Ch. aureus, id. Brownish yellow, a black perpendicular stripeacross the eyes, and twenty dark longitudinal bands on the sides.

Holacantlms septentrionalis, id., allied to annularis; but the dorsal andabdominal fins are not prolonged into points; about twelve blue longitudinalstripes. D. 13,18 ; A. 3, 18.

A new genus, Hypsinotus, has been instituted by the same naturalist, aftera figure by Burger. It is characterized by the position of the ventral finsclose to the anus, by the lowness of the soft dorsal fin; the body is nearly ashigh as it is long. The fish is brick-red. B. 6 ; D. 8, 27; A. 3, 26. Thegenus is placed near Drepane.

Another new genus, Histiopterus, by the same author, is placed nearTaurichthys and Heniochus, which it resembles in the figure of the body.The dorsal fin is very high, and presents four strong spines; head coveredwith asperities, teeth setiform, no scales on the fins. It includes two spe-cies : H typos, D. 4, 27; A. 3, 11. The third ray of the dorsal fin thelongest. If. acutirostris, the snout shorter, and the fourth ray thelongest.

Valenciennes has described, in the Ichthyologie des Canaries, a fish,approaching the genus Brama, as a new genus, Neobrama Webbii. Thesame fish had been already named by Lowe Polymixia nobilis, which namehas the priority. Valenciennes gives the following characters : Corpusoblongum, squamis asperrimis tectum; caput parvum, squamosum, rostrumac mandibula superior nuda; maxilla inferior squamosa, infra cirris duobuslongis symphysi afiixis instructa; dentes in maxillis, in palato, in vomere acin lingua minuti, creberrimi, velutini; ossa opercularia inermia, squamosa,prajter interoperculum nudum, cutaceum; pinnae dorsales coadnatae, ventralesradiis ramosis septem; membrana branchiostega radiis quatuor.