Assertion: pygmy seahorse | /r/HasAspect | single gill opening
Facets:
value: on the back of the head
type: LOCATION
Source sentences:
text: Apart from their extremely small size, they have a single gill opening on the back of the head (all other seahorses have a pair of gill openings either side of the head) and the young are brooded within the male’s trunk rather than a pouch on the tail.