- Posterior end of male is expanded to a copulatory bursa
- Has two spicules that are fused at their distal ends
- Has two broad lateral lobes and a smaller dorsal lobe
- Fleshy rays support both lateral and dorsal lobes
- Arrangement of rays within bursa is a characteristic for each species
- N. americanus: Dorsal ray branches at base into 02 portions; Also, base of dorsal and dorsolateral rays is short
