6 POLYPTEKIDJK. 



twelfth to sixteenth transverse series of scales. Anal fin with 11 to 15 rays, Pectoral 

 fin with 36 to 42 rays, reaching beyond the vertical of the first spine of the dorsal. 

 Scales smooth or slightly rugose, in 63 to 70 transverse series, 46 to 54 round the body. 



Greyish or greenish olive above, the young with ten to thirteen cross-bars on the back 

 and two or three stripes along the sides of a darker shade ; these markings become more 

 indistinct or disappear entirely in the adult ; a few scattered black spots sometimes 

 present on the body ; paired fins with more or less distinct transverse streaks or series 

 of spots, the other fins without spots ; the ventral, anal, and caudal sometimes tinged 

 with red ; belly lemon-yellow ; iris yellow. 



The largest specimen examined by me measures 720 millimetres. The species 

 reaches a length of at least 820 millimetres according to Steindachner. 



Out of forty-four specimens examined, four have 14 spines in the dorsal fin, nine 

 have 15, twenty have 16, nine have 17, and two have 18. 



This species appears to be confined to the Nile, Lake Rudolf, and the Chad Basin ; 

 the statement as to its occurrence in the Senegal requires confirmation. The above 

 description is drawn up from the following examples : — 



4 3 miles south of Damietta, in freshwater canal connecting Nile with L. Menzaleh. — J. C. 



Mitchell, 8-9.1895. 

 2 Mansurah, Damietta branch of Nile. — Harrington and Hunt, 1898. 

 1 Cairo. — Riippell, 1833. 

 1 Nile near Cairo ; bought in Boulak Fish Bazar, Cairo. — Loat, 15.3.99. 



1 Kawa, White Nile.— Loat, 5.1.01. 



C> Goz abu Gumah, White Nile.— Loat, 1.5.01. 



2 Gharb-el-Aish, White Nile.— Loat, 5.4.01. 

 24 Fashoda, White Nile.— Loat, 1-7.4.01. 



1 In a kore near Kerro, White Nile. — Loat, 8.1.01. 

 1 Mouth of Lake No, White Nile.— Loat. 19.2.01. 

 1 Bahr-el-GebeL— Capt. Flower, 7.4.00. 



P. bichir is represented in West Africa (Senegal, Gambia, Niger) by a very closely 

 allied species, P. lapradii, Stdr., often difficult to distinguish. This differs in having 

 the anterior part of the head broader and flatter, the interocular region flat, its width 

 at least three times the diameter of the eye in the adult (twice or twice and one-third 

 in the young), and not less than the distance from the eye to the spiracle. The 

 dorsal spines vary from 13 to 15 ; of the thirty-two specimens examined by me, six 

 have 13 spines, six have 15, and twenty have 14 ; 60 to 68 scales along the body, 46 

 to 52 round the body. The colour and markings are the same as in P. bichir, but the 

 latter are usually better defined. The length of the specimens in the British Museum 

 varies between 94 and 740 millimetres. 



A specimen with external gills from the Bahr Tondi (Bahr-el-Ghazal) has long 

 ago been described and figured by Schweinfurth ; it measured 250 millimetres, and 



