THE 



FOURTH ORDER OF FISHES. 



MALACOPTERYGII APODES. 



May be considered as forming but one natural family, 

 which is that of 



Anguilliformes, 



Fishes which have all an elongated form, a thick and 

 soft skin which scarcely suffers their scales to ap- 

 pear, but few crests, and no cceca. Almost all have 

 natatory bladders, which frequently exhibit singular 

 forms. 



The great genus, 



Mur^na, L., 



Is recognized by small opercula, surrounded concen- 

 trically with rays \ and enveloped, as well as the rays, 



1 None of these fishes, as far as we know, want either opercula or 

 rays, as some naturalists have supposed. The common muraena has 

 seven rays on each side, the Marcena colubrina has twenty-five ; 

 these rays are even very strong in the Synbranckus, in which the 



