Knotted thread hydroid
- kingdom: Animalia
- phylum: Cnidaria
- class: Hydrozoa
- order: Leptothecata
- family: Campanulariidae
- genus: Obelia
- species: Obelia geniculata
Talcahuano
Biobío
Chile
Lysekil
Västra Götaland
Sweden
Scarborough
England
United Kingdom
New Haven