A detailed comparison of the scales of Trinectes maculatus (Bloch and Schneider) and T. inscriptus (Gosse) has demonstrated species specific differences valid for taxonomic purposes. A complex hinged joint attaching very large cteni to the scale plate characterizes both species. The large cteni are associated with a marked increase in skin surface which, in turn, is combined with an apparent increase in the cutaneous vascular bed suggesting a secondary respiratory and excretory function. The rigid skin flaps produced by the cteni may also be associated with a hydrodynamic "spoiler" mechanism. The lateral-line canal in both species is uniquely composed of tubes lying end to end with no ancillary scale appendages.