In heraldry, the term sea-lion (sometimes called a morse)[1] refers to a legendary creature that has the head and upper body of a lion, but with webbed forelimbs and a fish tail.[2] These occur most frequently as supporters, but also occur as crests and occasionally as charges.[1] Sea-lions are frequently found in "sejant" or "sejant-erect" (sitting upright) attitudes, but may also be found "naiant" (horizontally, as if swimming) or "assurgeant" (issuing from the waves of the sea).[1]
The heraldic device comes from Manila's colonial arms, where the sea-lion represents the islands as an ultramar (overseas) possession of Spain; the lion is ultimately derived from the arms of Castile and León.
"On the upper half of the coat of arms is a castle of gold on a red field, with a door and windows in blue, atop the shield a crown. On the lower half, on a blue field is a figure half lion half dolphin in silver, with colored claws and tongue, holding in its paw an unsheathed sword..."