The anterior part of the saccule exhibits an oval thickening, the "'macula acustica sacculi "', or macula, to which are distributed the saccular filaments of the vestibular branch of the vestibulocochlear nerve, also known as the statoacoustic nerve or cranial nerve VIII.
22.
The genus is characterized by a prolongation in the size of the symphysial pair of teeth relative to that of the other teeth in the outer row of the upper jaw ( nosferatuform teeth ); breeding pigmentation that consists of darkening of ventral area extending over nostrils, opercular series, and pectoral fins; depressed dorsal fin rarely expands beyond anterior third of caudal fin; and an elongated, elastic, smooth caecum adhered to a saccular stomach.
