Search results
Results from the WOW.Com Content Network
Cephalopods are widely regarded as the most intelligent of the invertebrates and have well-developed senses and large brains (larger than those of gastropods). [13] The nervous system of cephalopods is the most complex of the invertebrates [14] [15] and their brain-to-body-mass ratio falls between that of endothermic and ectothermic vertebrates.
Cephalopod molluscs such as this cuttlefish can change color rapidly for signaling or to match their backgrounds. Active camouflage or adaptive camouflage is camouflage that adapts, often rapidly, to the surroundings of an object such as an animal or military vehicle. In theory, active camouflage could provide perfect concealment from visual ...
Orthoceras is a genus of extinct nautiloid cephalopod restricted to Middle Ordovician-aged marine limestones of the Baltic States and Sweden. This genus is sometimes called Orthoceratites . Note it is sometimes misspelled as Orthocera , Orthocerus or Orthoceros .
A siphon is an anatomical structure which is part of the body of aquatic molluscs in three classes: Gastropoda, Bivalvia and Cephalopoda (members of these classes include saltwater and freshwater snails, clams, octopus, squid and relatives). Siphons in molluscs are tube-like structures in which water (or, more rarely, air) flows.
The body chamber or living chamber in shelled cephalopod mollusks is an equivalent space, and is also sometimes called the body whorl. It is the outermost or last chamber in the shell of a nautiloid or ammonoid. [2]
Cephalization is a characteristic feature of any animal that habitually moves in one direction, thereby gaining a front end. In practice, this primarily means the bilaterians, a large group containing the majority of animal phyla. [3]
Cutaway of a nautilus shell showing the chambers. The phragmocone is the chambered portion of the shell of a cephalopod.It is divided by septa into camerae.. In most nautiloids and ammonoids, the phragmocone is a long, straight, curved, or coiled structure, in which the camerae are linked by a siphuncle which determines buoyancy by means of gas exchange.
Other mollusks include gastropods, scaphopods and bivalves. Traditionally, the most common classification of the cephalopods has been a four-fold division (by Bather, 1888), into the orthoceratoids, nautiloids, ammonoids, and coleoids. This article is about nautiloids in that broad sense, sometimes called Nautiloidea sensu lato.