276 SILURID.E. 



3. HETEROBRANCHUS ISOPTERUS. 



Bleek. Nat. Verh. Wet. Haarlem, sviii. 1863, no. 2, p. 108, pi. xxii. fig. 1 ; Giinth. 



Cat. v. p. 23 (1864) ; Bouleng. Proc. Zool. Soc. 1907, p. 1096. 

 JSeterobranchus macronema, Bleek. 1. c. p. 109, pi. xxi. rig. 1. 



Depth of body 6 to 6| times in total length, length of head 3J to 3^ 

 times. Head If 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 4| times in length of head ; occipital fontanelle small, in 

 advance of occipital process ; eye small, 1\ or 3 times in length of 

 snout, h\ or 6 times in interorbital width, which is a little less than 

 \ length of head ; width of mouth ■§ length of head ; band of prse- 

 maxillary 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 prsemaxillary band ; nasal barbel a little shorter than head ; 

 maxillary barbel \\ to 1^ times length of head, extending to extremity 

 of pectoral spine or to base of ventral ; inner mandibular barbel f- 

 length of outer, a little shorter than the nasal. 18-20 gill-rakers on 

 first arch. Dorsal 30-32, its distance from occipital process J 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 f length of head, the 

 spine feebly serrated on the outer edge and measuring f the length of 

 the fin. Ventral midway between end of snout and base of caudal. 

 Caudal a little more than \ 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. Hgr. Nyankoma, Gold Coast. R. B. N. Walker, Esq. (C.) ; 



Dr. A. Giinther (P.). 



2. Hgr. Infoan, R. Oflfin. „ 



3-4. Yg. W. Africa. C. 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. 



