Definition

Noun: 1. A cephalopod mollusk: The pearly nautilus is a marine animal belonging to the cephalopod class, known for its distinctive, coiled external shell. It is found in the deep slopes of coral reefs in the Indo-Pacific region. Its shell has a series of internal, chambered partitions that appear pale and lustrous.

Usage

• The pearly nautilus is often studied by biologists for its unique buoyancy system.
• Divers rarely see a live pearly nautilus because it inhabits deep ocean waters.
• The beautiful, coiled shell of the pearly nautilus is a classic example of a logarithmic spiral in nature.

Advanced Usage

• "Chambered nautilus": This is a common alternative name for the pearly nautilus, emphasizing the segmented internal structure of its shell.
  • The chambered nautilus, or pearly nautilus, builds new, larger chambers as it grows.

Variants and Related Words

• Nautilus (n): The broader genus name () to which the pearly nautilus belongs. Other species include the emperor nautilus.
• Cephalopod (n): The class of mollusks that includes the nautilus, squid, octopus, and cuttlefish.

Synonyms

• Chambered nautilus: The most direct synonym.
• Nautilus pompilius: The scientific binomial name for the species.

Related Phrases

• Living fossil: A term sometimes used to describe the pearly nautilus, as it is the last surviving genus of a once vast and ancient group of shelled cephalopods.
  • The pearly nautilus is often called a living fossil due to its ancient lineage.

Noun

1. cephalopod of the Indian and Pacific oceans having a spiral shell with pale pearly partitions