Search results
Results From The WOW.Com Content Network
Cephalopods are thought to be unable to live in fresh water due to multiple biochemical constraints, and in their >400 million year existence have never ventured into fully freshwater habitats. [10] Cephalopods occupy most of the depth of the ocean, from the abyssal plains to the sea surface, and have also been found in the hadal zone. [11]
All extant cephalopods have a two-part beak, or rostrum, situated in the buccal mass and surrounded by the muscular head appendages. The dorsal (upper) mandible fits into the ventral (lower) mandible and together they function in a scissor-like fashion. [1] [2] The beak may also be referred to as the mandibles or jaws. [3]
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.
Cephalopods, as active marine predators, possess sensory organs specialized for use in aquatic conditions. [1] They have a camera-type eye which consists of an iris, a circular lens, vitreous cavity (eye gel), pigment cells, and photoreceptor cells that translate light from the light-sensitive retina into nerve signals which travel along the optic nerve to the brain. [2]
An ammonitic ammonoid with the body chamber missing, showing the septal surface (especially at right) with its undulating lobes and saddles. The ancestors of coleoids (including most modern cephalopods) and the ancestors of the modern nautilus, had diverged by the Floian Age of the Early Ordovician Period, over 470 million years ago.
Arms and buccal mass of the squid Taningia danae.As in other Octopoteuthidae, the tentacles are absent in adults. Oral view of the bobtail squid Semirossia tenera Head and limbs of the bobtail squid Rossia glaucopis Oral view of male Bathypolypus arcticus with hectocotylus on arm III (left) Cephalopod suckers and configuration of suckers on tentacular club Serrated suckers of a giant squid ...
Neocoleoidea (most living cephalopods) Coleoidea [ 1 ] [ 2 ] or Dibranchiata is one of the two subclasses of cephalopods containing all the various taxa popularly thought of as "soft-bodied" or "shell-less" (i.e. octopus , squid and cuttlefish ).
The elongate jewel squid (Histioteuthis reversa), so called because the photophores festooning its body make it appear bejewelled. Diagram of a cephalopod's photophore, in vertical section. A photophore is a glandular organ that appears as luminous spots on marine animals, including fish and cephalopods. The organ can be simple, or as complex ...