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Show 234 MR. G. A. BOULENGER ON THE [Mar. 18, 5. Contributions to the Ichthyology of the Congo.-I. On some new Fishes from the French Congo. By G. A. BOULENGER, F.R.S. [Received March 1, 1902.] (Plates XXII.-XXIV.1) The British Museum has recently received from its excellent correspondent Mr. G. L. Bates a single fish obtained by him in the Ja River, flowing into the Sanga, an affluent of the right bank of the Congo, and this fish proves to belong to an un-described species which requires the establishment of a new genus of Siluridse. At the same time the Director of the Royal Brussels Museum has entrusted me, at the request of my friend M. L. Dollo, with the study of the Congo Fishes preserved in that establishment. Among these I have found a small series of specimens coming from the Lukula River (sometimes spelt Likuala), another affluent of the right bank of the Congo, parallel to the Sanga. This series contains examples of five species :-Marcusenius sphecodes Sauvage, Alestes kingsleyce Gunther, Auchenoglanis ballayi Sauvage (all three previously known from the Ogowe only, and therefore new to the Congo system), and two new forms which are now described under the names of Labeo lukula?. and Chilochromis duponti. ALLABENCHELYS, g. n. Intermediate between Clarias and Clariallabes. Agreeing with the former in the free border to the eye, with the latter in the sides of the head being unprotected by bone. ALLABENCHELYS LONGICAUDA, sp. n. (Plate XXII. figs. 1, la.) Depth of body 12 times in total length, length of head 6 times. Head 1-L as long as broad, smooth above, the bony casque, in the middle, only one third the width of the head ; postorbital shield narrow; supraoccipital process acutely pointed ; a small frontal fontanelle ; eye very small, its diameter 4 times in length of snout and 6 times in interorbital width; latter not quite half length of head ; band of premaxillary teeth 5 times as long as broad ; vomerine teeth conical, in a crescentic band, which, in the middle, is nearly as broad as the prsemaxillary band. Nasal barbel nearly half as long as head; maxillary barbel as long as head, reaching middle of pectoral spine; outer mandibular barbel | length of head, inner \. Gill-rakers moderately long, 12 on anterior arch. Clavicles hidden under the skin. Dorsal fin with 80 rays, anal with 60, both narrowly separated from the caudal; the distance between the origin of the dorsal and the occipital 1 For explanation of the Plates, see p. 237. |