APPENDIX C. 
249 
also are coalescent into a single bone_, without median suture ; their 
dentition is the same as that of the upper jaw^ but there are three 
canine teeth, the central tooth standing in front of the jaw, and 
fitting between the upper canines. The maxillary is very small, 
attached to the extremity of the intermaxillary. Palate toothless. 
Nostrils in front of the eye, close together, the posterior wide, open. 
Gill-openings wide, the gill membranes being separate ; gill-rakers 
short, lanceolate. 
For our first acquaintance with the fishes of this genus we are 
indebted to Joannis, who gives a description and figure which do 
not leave any doubt as to the generic affinity of the fishes found by 
him, and rediscovered by Mr. Petherick on the Upper Nile. I have 
long hesitated to separate them specifically, but as Joannis says that 
there are only fifteen scales in a transverse row, and as he represents 
in the figure the scales of a corresponding size, it appears probable 
that the Nile is inhabited by two distinct species. They must be 
very scarce, as Joannis and Petherick are the only travellers who 
had the good fortune of meeting with them. It is also worthy of 
notiee that only two examples were in the extensive collections 
made by Mr. Petherick, which appears to confirm the remark made 
by Joannis, that these fishes are always found in pairs. 
Ichthyborus microlepis, Gthr. (Plate II., Fig. A.) 
D. 15—17. A. 14—15. P. 14—15. V. 10. L. lat. 100. 
L. transv. 12/14. 
The height of the body is contained four times and three-fourths 
or five times and one-fourth in the total length (without caudal) , 
