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. 



[Keceived March 1, 1902.] 

 (Plates XXII.-XXIV.^) 



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 Giinther, Auchenoglanis hallayi 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 Laheo lukidce, and Ghilochromis duponti. 



Allabenchelys, g. n. 



Intermediate between Clarias and Glariallahes. 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 1 2 times in total length, length of head 6 times. 

 Head 11 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 prsemaxillary teeth 5 times as long as 

 broad ; vomerine teeth conical, in a crescentic band, which, in the 

 middle, is nearly as broad as tbe prsemaxillary band. Nasal 

 barbel nearly half as long as head ; maxillary barbel as long as 

 head, reaching middle of pectoral spine ; outer mandibular barbel 

 I 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. 



