XXI OSTARIOPHYSI REF 
number 3 to 5 only. The fins never bear pungent spines, and 
the ventrals have 6 to 15 rays. Barbels are absent. In most 
of the herbivorous forms the brain-case is produced forward to 
the nasal capsule, whilst in most of the carnivorous forms they 
a) 
Wk dy) 
Fic. 349.—Open mouths of Characinidae. (After Miiller and Troschel.) A, Macrodon 
trahira ; B, Piabucina argentina; C, Brycon falcatus ; D, Chalceus angulatus ; 
E, Serrasalmo rhombeus ; F, Distichodus niloticus. 
are separated by an interorbital septum; but there are exceptions 
to this correlation, and as otherwise closely related genera may 
differ in this respect, I have not been able to make use of the 
character in defining sub-families. 
VOL. Vil 2°P 
