[Ostracoda] One of a pair of external male genitalia (referred to by some authors as the penisor hemipenis) which in myodocopids is a symmetrically paired structure but in halocyprids is a single structure on the right side of the caudal furca; an important taxonomic character (male,caudal furca/cop.appendage ).

Alternative form for copulatory appendage : copulatory organ.