XXI OSTARIOPHYSI 583 
Homaloptera in habit, with two gill-clefts on each side, an upper 
and a lower, a tadpole-lke mouth without barbels, and a small, 
free air-bladder, should probably be regarded as the type of a 
fifth sub-family. 
Many of the genera of the Cyprininae are partly founded on 
the shape and the disposition of the 
pharyngeal teeth, which, adapted to 
various requirements, may be conical, 
hooked, spoon-shaped, molariform, ete., 
ete. The importance attached to the dis- 
position of these teeth in one, two, or 
three series for the definition of genera, Fic. 352.—Lower pharyngeals of 
has been rather exaggerated.! Bor oe 
The Cyprinids constitute the majority of the freshwater fishes 
in Europe, Asia, and North America; they are comparatively 
few (about 100 species) in Africa, where they coexist with the 
Fic. 353.—Labeo falcifer, from the Congo, showing nuptial tubercles on the snout. 
t nat. size. 
Characinids. Some, like the Carp (Cyprinus carpio) and the 
Tench (Tinea vulgaris), are sluggish, except during the breeding 
season, when they show great excitement and indulge in leaps 
out of the water; others, like the Bleak (Alburnus lucidus) are 
constantly on the move in large shoals near the surface; whilst 
others again, like the M’Biriki of Lake Tanganyika (Barbus 
tropidolepis), behave after the manner of Salmon and Trout, 
1 For an illustrated account of the principal types of pharyngeal teeth, ef. 
Heckel, Russegger’s Reisen, i. p. 1001, pl. i. (1843). On their variations in certain 
European species, cf. Heincke, Leuckart Festschrift, p. 85 (1892), 
