310 FISHES. 



c. Pharyngeal bones very broad and strong ; the lower 

 7 to 10 teeth on each side, greatly enlarged and trun- 

 cate; the teeth on the upper part of the bone small, 

 as usual in the family. . . PLACOPHARYNX, 2. 



cc. Pharyngeal bones not especially enlarged; the teeth 

 strongly compressed, of the usual type. ' 



MYXOSTOMA, 3. 

 bb. Air bladder in two parts. 



d. No lateral line; fontanelle present; lips plicate; no 

 rnandibulary sheath ; scales large j ventral rays 9. 



MlNYTREMA, 4, ERIMYZON, 4, 5. 



dd. Lateral line well developed ; lips tuberculate. 

 e. Fontanelle distinct ; no mandibulary sheath. 

 /. Scales moderate, not crowded forwards, about 

 equal over the body ; body long and little com- 

 pressed; head transversely concave between 

 orbits, long and flattened ; the physiognomy 

 being therefore peculiar ; ventral rays 9. 



HYPENTELIUM, 6. 



ff. Scales small, smaller anteriorly and much 

 crowded; head transversely convex between 

 orbits ; ventral rays normally 10. 



CATOSTOMUS, 7. 



* Body much elongated, sub-cylindrical forwards ; dorsal elongate, 

 falciform, of 30 or more rays ; fontanelle obliterated by the 

 union of the parietal bones. (CydeptinoB.) 



g. Mouth small, subinferior, with papillose lips ; scales rather 



small CYCLEPTUS, 8. 



*** Body oblong oval, compressed ; dorsal elongate, elevated in 

 front, of 20 or more rays; fontanelle present. (Buba- 

 lichthyince.) 

 h. Dorsal rays about 30 in number (24 to 33) ; anal rays about 



10 (9 to 12) ; scales large. 

 i. Pharyngeal bones narrow, with the teeth relatively thin and 



j. Mouth small, inferior, protractile downwards ; dorsal fin 

 often greatly elevated, , . , CARPIODEB, 9. 



