Ammonite vs. Nautilus

Ammonitenoun

An explosive prepared from ammonium nitrate; amatol.

Ammonitenoun

Any of an extinct group of cephalopods of the subclass Ammonoidea; a fossil shell of such an animal.

Ammonitenoun

A fossil cephalopod shell related to the nautilus. There are many genera and species, and all are extinct, the typical forms having existed only in the Mesozoic age, when they were exceedingly numerous. They differ from the nautili in having the margins of the septa very much lobed or plaited, and the siphuncle dorsal. Also called serpent stone, snake stone, and cornu Ammonis.

Ammonitenoun

one of the coiled chambered fossil shells of extinct mollusks

Nautilusnoun

A marine mollusc, of the family Nautilidae native to the Pacific Ocean and Indian Ocean, which has tentacles and a spiral shell with a series of air-filled chambers, of which Nautilus is the type genus.

Nautilusnoun

A kind of diving bell that sinks or rises by means of compressed air.

Nautilusnoun

The only existing genus of tetrabranchiate cephalopods. About four species are found living in the tropical Pacific, but many other species are found fossil. The shell is spiral, symmetrical, and chambered, or divided into several cavities by simple curved partitions, which are traversed and connected together by a continuous and nearly central tube or siphuncle. See Tetrabranchiata.

Nautilusnoun

The argonaut; - also called paper nautilus. See Argonauta, and Paper nautilus, under Paper.

Nautilusnoun

A variety of diving bell, the lateral as well as vertical motions of which are controlled, by the occupants.

Nautilusnoun

a submarine that is propelled by nuclear power

Nautilusnoun

cephalopod mollusk of warm seas whose females have delicate papery spiral shells

Nautilusnoun

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

Nautilus

The nautilus (from the Latin form of the original Ancient Greek: ναυτίλος, 'sailor') is a pelagic marine mollusc of the cephalopod family Nautilidae. The nautilus is the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina.