rCHTHIOBORUS.— HEM1STICHODUS. 



253 



26-27. Ad. 



28. Ad. 



29. Hgr. 



30. Ad. 



Polkom, Baro R. (Sobat). 



Mouth of Lake No, 



White Nile. 

 Lake No, White Nile. 

 Fort Lamv, Shari River. 



Mr. P. C. Zaphiro (C.) ; 



W.N. McMillan, Esq. (P.) 

 L. Loat, Esq. (0.). 



Capt. G. B. Gosling (P.). 



13. HEMISTICHODUS. 

 Pellegr. Bull. Mus. Paris, 1900, p. 352. 



Snout moderately long ; mouth large, both jaws freely movable 

 vertically, the lower overlapping the upper on the sides ; pharyngeal 

 orifice much restricted ; maxillary fused with preemaxillary ; upper jaw 

 toothless in front ; sides of upper jaw bent inwards posteriorly, abutting 

 against a large process of the mandible ; teeth on sides of upper jaw and 

 in lower forming a single series, very small, closely set, with bicuspid 

 crowns with long slender shafts. Cheek covered by the suborbitals ; 

 nostrils on upper surface of snout, at a short distance from the eye, close 

 together, separated by a valvular flap ; gill-membranes free from isthmus. 

 Body elongate, compressed. Scales small, strongly ciliated ; lateral line 

 straight, along the middle of the side ; a scaly process at base of ventral. 

 Dorsal with 13 to 15 rays, above ventrals; anal with 11 or 12 rays; 

 adipose fin small. 



Ogowe. 



1. HEMISTICHODUS VAILLANTI. 

 Pellegr. 1. c, and Bull. Soc. Philom. (9) ix. 1907, p. 24, pi. i. fig. 1. 



Fig. 193. 



Hemistkhodus vailhnii, with enlarged view of open mouth. 

 Ngomo. 



Depth of body 4£ to 5| times in total length, length of head 3§ to 4| 

 times. Snout rounded, flat above, projecting beyond lower jaw, as long 

 as eye, which is 3 to 3J times in length of head and nearly equate 



