12 Synopsis of the Fresh Water Fishes, 



Head with the profile triangular, thin, compressed, rounded 

 above. 



Mouth rather large, with the gape linear-elliptical. Lower 

 jaw passing beyond the upper. The intermaxillaries form the 

 entire arch of the upper jaw and are very extensible, and when 

 retracted enter between the orbits. 



Teeth on the intermaxillaries and dentary numerous, card- 

 like, with recurved summits : two small patches of similar teeth 

 on the chevron of the vomer. 

 Lips thin. 



Tongue slender, sub-linear, and destitute of teeth. 

 Lower pharyngeal bones double, together forming a nearly 

 equilateral triangle, separated by a furrow in the middle, and 

 with a posterior sinus : covered by card-like teeth. 

 Branchiostegal rays six. 



Nares two, subrotund, of nearly equal size, in a bare oval 

 space ; the posterior one immediately before the eye. 



Operculum with an angular spine, preoperculum deeply ser- 

 rated at the inferior margin and for a short distance above the 

 angle : first infra-orbital serrated. 



The various bones of the opercular apparatus and the head 

 above to the maxillary bones covered by scales like those of 

 the body. 



Lateral line obsolete. 



Dorsal long, commencing at the nape, and the greater portion 

 sustained by spinous rays, which decrease in length from the 

 middle of the fin towards the soft portion : the latter with a 

 short base, higher than long, and exceeding the height of the 

 spinous portion. 



Anal long, commencing at about the middle of the body 

 and a short distance behind the anus ; the spinous portion of 

 extreme length, composing by far the greater portion of the fin ; 

 soft portion similar in size to the corresponding part of dorsal ; 

 the entire fin has nearly the same proportions as the latter. 

 Caudal not emarginate. 



