ORDER IV. The ABDOMINALES, have the belly-fins placed behind the pectoral fins.—This order contains 16 genera, viz. Cobitis, Amina, Silurus, Teuthis, Loricaris, Salmo, Fistularia, Elox, Elops, Argentina, Atherina, Mugil, Exocetus, Polynemus, Clupea, Cyprinus.