December 4. Philippine Marine
Featuring Nudibranchs or Sea Slugs of
Amstar Company, Inc. Perf. 14.
Blocks of 4, Miniature Sheets of 16; Souvenir
Sheets of 6
Se-tenant Blocks of Four
7p Glossodoris colemani
7p Chromodoris sp.
Miniature Sheets of 16 (6,250)
Souvenir Sheets of 6 + 2 labels (5,000)
First Day Covers: Manila
Name for a marine
gastropod mollusk that lacks a shell as an
adult and is usually brightly colored.
slugs, or nudibranchs, are distributed throughout the world, with
the greatest numbers and the largest kinds found in tropical waters.
They creep along the bottom or cling to submerged vegetation,
usually in water just below the low tide line. Members of a few
species swim on the surface in open ocean. Most sea slugs are under
1 in. (2.5 cm) long, although the largest, found in the Great
Barrier Reef of Australia, reaches 12 in. (30 cm). Regarded by many
people as the most beautiful of marine animals, sea slugs display a
great array of solid colors and patterns.
have feathery structures (ceratia) on the back, often in a
contrasting color. Most sea slugs have two pairs of tentacles on the
head, used for tactile and chemosensory reception, with a small eye
at the base of each tentacle. Sea slugs graze on small sessile
animals such as coelenterates, sponges, and bryozoans. Certain sea
slugs that feed on corals and sea anemones ingest the stinging cells
of their prey without discharging them; these then pass from the
slug's digestive tract to the ceratia, where they are used by the
slug for its own defense. Sea slugs are classified in the phylum
Mollusca, class Gastropoda, subclass
Opisthobranchia, order Nudibranchiata.