CLARIALLABES, 269 = is 4 length of head and a little less than width of mouth; band of premaxillary teeth hardly 4 times as long as broad; vomerine teeth pointed, forming a crescentic band which is a little narrower than the premaxillary band; nasal barbel 2 to 2 length of head; maxillary barbel nearly as long as head; inner mandibular barbel 3 to # length of head, outer nearly as long as head. Gill-rakers moderately long, 12 to 15 on anterior arch. Clavicles scarcely distinguishable under the skin. Clariallabes melas.
Type. 4.
Dorsal 105-115, its distance from occipital process 4 length of head. Anal 88-90. Both dorsal and anal united with caudal, which measures % length of head. Pectoral nearly } length of head, its spine serrated on both edges and about § the length of the fin. Ventral J? to 2 times distant from root of caudal as from end of snout. Uniform blackish brown.
Total length 260 millim.
Lower Congo.
1. Type. Lower Congo. M. F. Hens (C.).
2. Her. Congo?
3. Skel. 2
270 SILURIDA.
4. GYMNALLABES.
Giinth. Ann. & Mag. N. H. (3) xx. 1867, p. 111; Bouleng. Proc. Zool. Soc. 1907, p.1093.
Degraded, anguilliform Clarias, with the sides of the head unprotected by bone, even the postorbital shield being absent, the pectoral and ventral fins very small, no free border to the eye, and the dorsal and anal completely united with the caudal.
A single species.
1. GYMNALLABES TYPUS.
Ginth. |. c. pl. ii. fig. A; Bouleng. 1. c.
Depth of body 14 to 15 times in total length, length of head 74 to 83 times. Head about 12 times as long as broad, the width of the bony part, in the middle, + to + width of head; occipital process acutely pointed ; eye very small; interorbital width less than width of mouth, about 3 length of head; band of premaxillary teeth 3 to 3} times as long as broad ; vomerine teeth pointed, forming a crescentic band which is narrower than the premaxillary band; a much developed lobe at the angle of the mouth; nasal barbel 3 to ~ length of head; maxillary Gymnallabes ty pus.
Type, after Giinther (1. ¢.). 4.
barbel a little longer than head ; inner mandibular barbel % to ? length of head, outer a little shorter than head. Gill-rakers moderately long, 10 on anterior arch. Clavicles hidden under the skin. Dorsal 98-110, its distance from occipital process 2 to # length of head. Anal 82-88. Dorsal and anal completely united with caudal, which is 3 to 3 length of head. Pectoral 3 to $ length of head, with a very short smooth spine. Ventral 2 to 24 times as distant from root of caudal as from end of snout. Uniform blackish brown, lighter brown on the belly. Total length 230 millim.
Lower Niger and Old Calabar.
1-2. Types. Old Calabar.
3. Ad. Ossomari, 8. Nigeria. Dr. W. J. Ansorge (C.).
GYMNALLABES.—CHANNALLABES. 271 Under the name of G. typus, forma heterocercalis, Lénnberg, Ofvers. Vet.-Akad. Forh. Stockholm, 1895, p. 184, has noticed a fish from Cameroon which differs from Giinther’s description and figure in the somewhat turned up caudal fin, giving it a heterocercal appearance, and in having the pectoral spine serrated on both sides, 5. CHANNALLABES.
Giinth. Ann. & Mag. N. H. (4) xii. 1873, p. 143 ; Bouleng. Poiss. Bass. Congo, p- 263 (1901), and Proc. Zool. Soc. 1907, p. 1094. Closely allied to the preceding, but still more degraded and eelshaped; pectoral fin rudimentary or absent, ventrals absent. Vertebrz 107.
A single species.
1. CHANNALLABES APUS.
Gymnallabes apus, Giinth. t. c. p. 142. Channallabes apus, Bouleng. ll. cc. pp. 264 and 1094, fig. Body extremely elongate and serpentiform; length of head 10 to 14 times in total length. Head 1} to 14 times as long as broad ; occipital process acutely pointed ; a soleshaped frontal fontanelle ; an oval occipital fontanelle, partly on the occipital process ; eye extremely small, nearly hidden under the skin in the adult; band of premaxillary teeth 3 times as long as broad ; Fig.225.
Channallabes apus.
Type (P. Z. 8.1907). 3.
yomerine teeth pointed, forming a crescentic band which is a little narrower; nasal barbel ® to # length of head; maxillary barbel as long as head or slightly shorter; inner mandibular barbel a little shorter than the nasal, outer mandibular a little shorter than the
272 SILURID.
maxillary. Gill-rakers moderately long, 9 to 10 on anterior arch. Dorsal 140-150, separated from occipital process by a space equal to or greater than length of head. Anal 125-150. Dorsal and anal completely united with caudal. Pectoral absent or reduced to a minute rudiment without spine. No trace of ventral. Vent at the anterior fourth of the total length. Uniform dark brown or black. Total length 310 millim.
Congo and Angola.
1. Type. Ambriz, Angola. J.J. Monteiro, Esq. (C.). 2. Ad. Siala Ntoto, Mayombe. Major Cabra (C.). 3-5. Her. Lower Congo. M. F. Hens (C.). 6. Yg. Monsembe, Upp. Congo. Rev. J. H. Weeks (P.). 7. Skel. i$ y 3 8. Ad. New Antwerp, Upp. Congo. Capt. Wilverth (C.). 9. Ad. Stanley Falls, 5 Rey. W. H. Bentley (C.). 10. Hgr. Banzyville, Ubanghi. Capt. Royaux (C.). 11, Ad. Congo ?
6. HETEROBRANCHUS.
Geoffr. Deser. Egypte, Poiss. (1809), part. ; Giinth. Cat. Fish. v. p. 21 (1864); Bouleng. Poiss. Bass. Congo, p. 265 (1901), Fish. Nile, p. 300 (1907), and Proe. Zool. Soc. 1907, p. 1094.
Distinguished from Clarias by the division of the dorsal fin into two parts, the posterior adipose and supported by the prolongations of the neural spines.
Vertebree 60-65.
Three species from Africa, and one from the Malay Archipelago. Synopsis of the Species.
D. 38-45; adipose fin 2-3 length of rayed dorsal; pectoral not more than } length of _ head ; 20-30 gill-rakers on anterior arch. 1, H. bidorsalis, I. Geoffr., p. 273. D. 29-34 ; adipose fin as long as or a little shorter than rayed dorsal ; pectoral not more than 3 length of head; 20-30 gillrakers on anterior arch . =. . . . «2. A. longifilis, C. & V., p. 274. D. 30-32; adipose fin as long as or a little shorter than rayed dorsal; pectoral 3 length of head; 18-20 gill-rakers on anterior lel tubes: talline die) = Weslaco yl tasoptenus, Bile pens
HETEROBRANCHUS. 273 1. HETEROBRANCHUS BIDORSALIS.
I. Geoffr. Deser. Egypte, Poiss. p. 305, pl. xvi. figs. 2 & 5, & pl. xvii. figs. 8 & 9 (1827) ; Giinth. Petherick’s Trav. ii. p. 220 (1869) ; Bouleng. Fish. Nile, p. 300, pl. liv. fig. 1 (1907), and Proc. Zool. Soe. 1907, p. 1095. Heterobranchus geoffroyi, Guy. & Val. Hist. Poiss. xv. p. 392 (1840). Heterobranchus senegalensis, Cuv. & Val. t. c. p. 397 ; Steind. Sitzb. Ak. Wien, Ix. 1869, p. 980.
Heterobranchus intermedius, Giinth. Cat. Fish. v. p. 22 (1864), and I. c. Depth of body 6 to 9 times in total length, length of head 2# to 3} times. Head very strongly depressed, 1} to 14 times as long as broad, its upper surface coarsely granulate in the adult; occipital process pointed, sometimes very obtusely; frontal fontanelle knife-shaped, 3 to 4 times as long as broad, 3 to 5 times in length of head; occipital fontanelle small, in advance of occipital process; eye 3 (young) to 63 times in length of snout, 6 to 103 times in interorbital width ; width of mouth a little less than interorbital width ; band of premaxillary teeth about 5 times as long as broad; vomerine teeth also villiform, forming a Fig.226.
cee TST pee Heterobranchus bidorsalis.
White Nile (F. N.). 4.
crescentic band which is 14 to 14 times as broad as the premaxillary band and may have a small central posterior process ; nasal barbel 3 to once length of head; maxillary barbel $ to 1} times length of head, extending to extremity of pectoral or between this point and root of ventral; outer mandibular barbel 1;/5 to 14 times as long as inner, which measures 1 to 13 times length of head. Gill-rakers rather short, 20 to 30 on anterior arch. Dorsal 38-45, its distance from occipital process 4/5 to § length of head ; adipose dorsal 2 to 3 as long as, as deep as or lower than, and commencing immediately behind, rayed dorsal, extending to base of caudal. Anal 50-57, extending to base of caudal. Pectoral 2 to 4 length of head, the spine smooth VOL, II. T
274 SILURIDA.
and measuring # to } the length of the fin. Ventral midway between end of snout and base of caudal, or a little nearer the latter. Caudal 2 to } length of head. Dark olive above, whitish beneath ; a dull orange or red edge to the dorsal, adipose, and caudal fins. Total length 770 millim. ; grows to 1220.
Nile, Chad Basin, Senegal, Niger.—Type (Paris Museum) apparently lost.
1, 2. Types of Khartum. J. Petherick, Esq. (C.).
LT.
intermedius.
3. Skel. t. - 4,5. Ad. & hgr. Goz Shebesha, White Nile. L. Loat, Esq. (C.). 6. Her. Goz abu Gumah, __,, PP 7. Ad., head. oe se a 8. Her. Fashoda, . Bs 9. Her. R. Shari-wasu at Maidugari. Capt. G. B. Gosling (P.). 10. Ad., head. Shari. ~ 11-13. Ad. & her. Kaédi, Senegal. M. P. Delhez (C.). 14-15. Ad. & her. Niger. W. A. Forbes, Esq. (P.). 2. HETEROBRANCHUS LONGIFILIS.
Cuv. & Val. Hist. Poiss. xv. p. 394, pl. eecexlvii. (1840) ; Giinth. Cat. Fish. v. p- 22 (1864), and Petherick’s Trav. ii. p. 221 (1869); Bouleng. Fish. Nile, p- 303, pl. liv. fig. 2 (1907), and Proc. Zool. Soc. 1907, p. 1095. Heterobranchus laticeps, Peters, Mon. Berl. Ac. 1852, p. 682, and Reise Mossamb. iv. p. 37, pl. vil. fig. 1 (1868); Bouleng. Poiss. Bass. Congo, p. 265 (1901). Depth of body 6 to 8 times in total length, length of head 3 to 32 times. Head less strongly depressed than in the preceding species, 14 to 12 times as long as broad, its upper surface coarsely granulate in the adult ; occipital process acutely pointed ; frontal fontanelle knife-shaped, 24 to 4 times as long as broad, 55 to 64 times in length of head; occipital fontanelle small, in advance of occipital process; eye 24 (very young) to 43 times in length of snout, 4 to 9 times in interorbital width ; width of mouth a little less than interorbital width ; band of premaxillary teeth 5 to 6 times as long as broad; vomerine teeth also villiform, forming a crescentic band, which is nearly as broad as or a little broader than premaxillary band; nasal barbel } to once length of head; maxillary barbel 1} to 2 times length of head, extending to end of pectoral or between this point and origin of anal; outer mandibular barbel 15 to 1} times as long as inner, which measures } to nearly once length of head. Gill-rakers rather short, 20 to 30 on anterior arch.
HETEROBRANCHUS. 275 Dorsal 29-34, its distance from occipital process 7 to % length of head ; adipose dorsal as long as or a little shorter and lower than rayed dorsal, commencing immediately behind or at a short distance from the latter. Anal 44-54, extending, like the adipose dorsal, to the base of the caudal fin. Pectoral 2 to + length of head, the spine feebly serrated on the outer border and measuring 4 (young) to $ the length of the fin. Ventral midway between end of snout and base of caudal, or a little nearer the latter. Caudal $ to ? length of head. Olive above, white beneath, sometimes with scattered black blotches; dorsal and anal fins pale olive, darker towards the edge, which may be margined with red; caudal fin yellowish or pale orange at the base, with a more or less distinct blackish crescentic band, sharply defined in front, shading off to yellow or red behind ; adipose dorsal fin often blackish at the end.
Total length 720 millim.
Nile, Omo, Niger, Congo, Zambesi.—Type in Paris Museum. Fig.227.
Heterobranchus longifilis.
Luxor (F.N.). 1.
Vg Gap. Nile.
2. Her. Luxor. L. Loat, Esq. (C.).
3. Skel. 5 5 4-9. Yo. Between Luxor and Assuan. 4 10. Ye. Assuan. i, 11-12. Yg. Kosheh, Nubia. a ae Whee Khartum. J. Petherick, Hsq. (C.). 14, Ad. Cojeb R. (Omo), 2500 ft. Mr. P. C. Zaphiro (C.). ; W.N. MacMillan, Hsq. (P.).
15. Her. Ergino R. (Omo), 3000 ft. 3 16. Her. Orah R., Lagos. Major G. E. Bruce (P.). 17-22. Yg. Aghberi, S. Nigeria. Dr. W. J. Ansorge (C.). 23. Ye. Kasai district, Congo. M. De Meuse (C.). 24,25. Ad.&yg. Monsembe, Upp. Congo. Rev. J. H. Weeks (P.). g2
276 SILURIDA.
3. HETEROBRANCHUS ISOPTERUS.
Bleek. Nat. Verh. Wet. Haarlem, xviii. 1863, no. 2, p. 108, pl. xxii. fig. 1; Giinth. Cat. v. p. 23 (1864) ; Bouleng. Proe. Zool. Soc. 1907, p. 1096. Heterobranchus macronema, Bleek. 1. c. p. 109, pl. xxi. fig. 1. Depth of body 6 to 64 times in total length, length of head 33 to 33 times. Head 12 times as long as broad, upper surface finely granulate; occipital process acutely pointed ; frontal fontanelle 3 to 4 times as long as broad, 3 to 42 times in length of head ; occipital fontanelle small, in advance of occipital process; eye small, 24 or 3 times in length of snout, 54 or 6 times in interorbital width, which is a little less than 4 length of head; width of mouth } length of head; band of premaxillary teeth 5 times as long as broad; vomerine teeth villiform, forming a crescentic band, which is as broad as or a little narrower than the premaxillary band; nasal barbel a little shorter than head ; maxillary barbel 1} to 1} times length of head, extending to extremity of pectoral spine or to base of ventral; inner mandibular barbel 2 length of outer, a little shorter than the nasal. 18-20 gill-rakers on first arch. Dorsal 30-32, its distance from occipital process 4 or + length of head; adipose dorsal as long as or a little shorter, lower than, and commencing a short distance behind, dorsal proper, narrowly separated from caudal. Anal 41-46. Pectoral 2 length of head, the spine feebly serrated on the outer edge and measuring ? the length of the fin. Ventral midway between end of snout and base of caudal. Caudal a little more than 4 length of head. Blackish brown above, whitish beneath ; fins with a narrow yellowish margin. Total length 170 millim.
Gold Coast.—Type in Leyden Museum.
1. Her. Nyankoma, Gold Coast. R. B. N. Walker, Esq. (C.); Dr. A. Giinther (P.).
2. Her. Infoan, R. Offin. an 3-4. Yg. W. Africa. ©. Swanzz, Esq. (C.).
7. DINOTOPTERUS.
Bouleng. Tr. Zool. Soc. xvii. 1906, p. 550, and Proc, Zool. Soc. 1907, p. 1097. As in the preceding, but sides of head naked, only the postorbital shield being present, and adipose dorsal fin small, not supported by bony rays.
A single species.