356 CLASSIFICATION OF FISHES. 



the fixed gills^ or the spiraculated aperture of the 

 AspredincB : and all their other points of structure agree 

 with the sub-families in which we have arranged them. 

 Thus, Cataphractus has the perfectly mailed body and 

 the two dorsals of the Loricarince ; Cyclopium has the 

 naked compressed body^ and the adipose tin of the" Pi- 

 melodince; while in Cetopsis there are all the general cha- 

 racters of the anguilhform Silu/'ince] except that it has 

 the minute vertical eyes oi Asjn-edo: hence it follows, 

 that all these become representations only of the present 

 group in their own circles ; they have, in shorty a strong 

 resemblance of analogy to Aspredo, but without any ab- 

 solute affinity^ seeing that the preponderance of their 

 general characters^ in all other respects, places them else- 

 where. The passage from the Aspredince to our next 

 division, appears to be made by two singular-looking 

 fishj which Gronovius erroneously places in the genus 

 Mystus : one of these has the minute vertical eyes of 

 Astroblepjus and Aspredo, with the body and fins of 

 Pimelodus, or Sorubium; while the other_, in all exter- 

 nal points^ evidently belongs to the same type as Spix's 

 Heterohranchus ; for both these latter have the elongated 

 head^ and the unequally lobed caudal, rounded at the 

 end of its divisions, which is such a general character 

 among the SorubiiKS, although no fishes among the 

 PimelodincE, that we know of, have the caudal fin so 

 constructed ; neither is the first dorsal ray, as in these, 

 slender and unarmed. 'We may thus trace the passage 

 from the Aspredince, and proceed to the next group. 



(289.) The SoRUBix.E constitute the last division of 

 this very extensive and intricate family. Although 

 possessing something of the general appearance of the 

 Pimelodijicp, they are readily distinguished from them, 

 and indeed from all the other silures, by an unusually 

 long and large head, having the muzzle very broad, 

 flattened, and prolonged over the under jaw ; so that 

 the mouth, by this formation, is situated beneath (^fig. 

 92.). For the comparatively recent discovery of this 

 highly interesting group, we are indebted to the re- 



