1898.] OF THE FAMILY MOHMIEIDjE. 787 



Head nearly twice as long as deep, upper profile straight, declivous ; 

 snout rounded, projecting a little beyond the mouth ; width o£ 

 mouth I length of snout ; teeth truncate, 12 in the upper jaw, 14 

 in the lower ; eye small, situated in the anterior third of the head, 

 its diameter 2^ times in length of snout or interorbital width. 

 Dorsal 43, | length of anal, originating a little nearer base of 

 caudal than head. Anal 63, originating considerably in advance of 

 dorsal (its 14th ray corresponding to the first dorsal ray), and at 

 equal distance from end of snout and base of caudal. Pectoral 

 a little more than ^ length of head, ventral nearly f . Caudal very 

 small, scaled at the base, with rounded lobes. Caudal peduncle 

 hardly as long as deep, ^ length of head. 95 scales in the lateral 

 line, Jl in a transverse line on the body, 18 in a transverse line 

 between dorsal and anal, 16 round caudal peduncle. Whitish, 

 finely speckled with brown. 



Total length 410 millim. 



Upper Congo. 



2. Petbocephalus. 



Petroceplialus, part., Marcusen, Bull. Ac. St. Petersb. xii. 1854, 

 p. 14, and Mem. Ac. St. Petersb. (7) vii. 1864, no. 4, p. 111. 



Petrocephalus, Gill, Proc. Ac. Philad. 1862, p. 443 (1863); 

 Bouleng. Ann. Mus. Congo, Zool. i. 1898, p. 2. 



Teeth in the jaws bicuspid, forming a single complete series on 

 the entire edge of both jaws (10-24 in the upper jaw, 18-36 in 

 the lower) ; minute conical teeth on the parasphenoid and on the 

 tongue ; mouth inferior, situated below the eyes. Nostrils close 

 together, close to the eye. Body short ; ventrals nearer pectorals 

 than anal. Dorsal and anal not very unequal in leugth. Vertebrae 

 42 (9 + 4-6 + 27-29). 



Synopsis of the Species. 



I. Dorsal 29-33 ; Anal 33-37 ; 12 scales round caudal 



peduncle ; lat. 1. 40-50. 

 Width of mouth J-J length of head ; caudal peduncle 



|-4 length of head 1. baueLacep. 



Width of mouth f length of head ; caudal peduncle f-f 



length of head 2. sauvaffUBlgr. 



II. Dorsal 20-28. 



A. 10 or 12 scales round caudal peduncle. 



D. 20-25; A. 31-33; lat. 1. 39-40 3. boveiC.&\. 



D. 21-24; A. 28-30; lat. 1. 37; I scales in a series 

 between dorsal and anal ; caudal peduncle 2^-3 times 

 as Ions as deep 4. balayi8a.\xv. 



D. 24-28 ; A. 30-33 ; lat. 1. 38-42 ; ^^ scales in a 



series between dorsal and anal ; caudal peduncle 3 



times as long as deep 5. simtis Sauv. 



12 



D. 27 ; A. 29 ; lat. 1. 40 ; — scales in a series between 

 dorsal and anal ; caudal peduncle 2^ as long as deep . 6. gliroides Vincig. 



B. 16 scales round caudal peduncle. 



D. 20-22; A. 25-29; lat. 1. 37^0 7. catostoma Qtths. 



