Baroque Pearl
From Wikipedia, the free encyclopedia, for the most part...

Baroque pearls are pearls with an irregular non-spherical shape.  Shapes can range from minor aberrations to distinctly ovoid, curved, pinch, or lumpy shapes.  Most cultured freshwater pearls are baroque because freshwater pearls are mantle-tissue nucleated instead of bead nucleated.  Cultured saltwater pearls can also be baroque, but tend to be more teardrop-shaped due to the use of a spherical nucleation bead. 

Octopus
Excerpts from Wikipedia, the free encyclopedia article;

 The octopus (plural octopuses) is a soft-bodied, eight-limbed mollusk of the order Octopoda.  Around 300 species are recognized, and the order is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids.  Like other cephalopods, the octopus is bilaterally symmetric with two eyes and a beak, with its mouth at the center point of the eight limbs.  The soft body can rapidly alter its shape, enabling octopuses to squeeze through small gaps.  They trail their eight appendages behind them as they swim.  The siphon is used both for respiration and for locomotion, by expelling a jet of water.  Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviorally diverse of all invertebrates.

 Octopuses inhabit various regions of the ocean, including coral reefs, pelagic waters, and the seabed; some live in the intertidal zone and others at abyssal depths.  Most species grow quickly, mature early, and are short-lived.  In most species, the male uses a specially adapted arm to deliver a bundle of sperm directly into the female's mantle cavity, after which he becomes senescent and dies, while the female deposits fertilized eggs in a den and cares for them until they hatch, after which she also dies.  Strategies to defend themselves against predators include the expulsion of ink, the use of camouflage and threat displays, the ability to jet quickly through the water and hide, and even deceit.  All octopuses are venomous, but only the blue-ringed octopuses are known to be deadly to humans.

 Octopuses appear in mythology as sea monsters like the Kraken of Norway and the Akkorokamui of the Ainu, and probably the Gorgon of ancient Greece.  A battle with an octopus appears in Victor Hugo's book Toilers of the Sea, inspiring other works such as Ian Fleming's Octopussy.  Octopuses appear in Japanese erotic art, shunga.  They are eaten and considered a delicacy by humans in many parts of the world, especially the Mediterranean and the Asian seas.

 The giant Pacific octopus (Enteroctopus dofleini) is often cited as the largest known octopus species.  Adults usually weigh around 15 kg (33 lb), with an arm span of up to 4.3 m (14 ft).  The largest specimen of this species to be scientifically documented was an animal with a live mass of 71 kg (156.5 lb).  Much larger sizes have been claimed for the giant Pacific octopus: one specimen was recorded as 272 kg (600 lb) with an arm span of 9 m (30 ft).  A carcass of the seven-arm octopus, Haliphron atlanticus, weighed 61 kg (134 lb) and was estimated to have had a live mass of 75 kg (165 lb).  The smallest species is Octopus wolfi, which is around 2.5 cm (1 in) and weighs less than 1 g (0.035 oz).

 External Characteristics

 The octopus is bilaterally symmetrical along its dorso-ventral axis; the head and foot are at one end of an elongated body and function as the anterior (front) of the animal.  The head includes the mouth and brain.  The foot has evolved into a set of flexible, prehensile appendages, known as "arms" that surround the mouth and are attached to each other near their base by a webbed structure.  The arms can be described based on side and sequence position (such as L1, R1, L2, R2) and divided into four pairs.  The two rear appendages are generally used to walk on the sea floor, while the other six are used to forage for food; hence some biologists refer to the animals as having six "arms" and two "legs".  The bulbous and hollow mantle is fused to the back of the head and is known as the visceral hump; it contains most of the vital organs.  The mantle cavity has muscular walls and contains the gills; it is connected to the exterior by a funnel or siphon.  The mouth of an octopus, located underneath the arms, has a sharp hard beak.

 The skin consists of a thin outer epidermis with mucous cells and sensory cells, and a connective tissue dermis consisting largely of collagen fibres and various cells allowing colour change.  Most of the body is made of soft tissue allowing it to lengthen, contract, and contort itself.  The octopus can squeeze through tiny gaps; even the larger species can pass through an opening close to 2.5 cm (1 in) in diameter.  Lacking skeletal support, the arms work as muscular hydrostats and contain longitudinal, transverse and circular muscles around a central axial nerve.  They can extend and contract, twist to left or right, bend at any place in any direction or be held rigid.

 The interior surfaces of the arms are covered with circular, adhesive suckers. The suckers allow the octopus to anchor itself or to manipulate objects.  Each sucker is usually circular and bowl-like and has two distinct parts: an outer shallow cavity called an infundibulum and a central hollow cavity called an acetabulum, both of which are thick muscles covered in a protective chitinous cuticle.  When a sucker attach es to a surface, the orifice between the two structures is sealed.  The infundibulum provides adhesion while the acetabulum remains free, and muscle contractions allow for attachment and detachment.

 The eyes of the octopus are large and are at the top of the head.  They are similar in structure to those of a fish and are enclosed in a cartilaginous capsule fused to the cranium.  The cornea is formed from a translucent epidermal layer and the slit-shaped pupil forms a hole in the iris and lies just behind.  The lens is suspended behind the pupil and photoreceptive retinal cells cover the back of the eye.  The pupil can be adjusted in size and a retinal pigment screens incident light in bright conditions.

 Nervous System and Senses

 The octopus (along with cuttlefish) has the highest brain-to-body mass ratios of all invertebrates; it is also greater than that of many vertebrates.  It has a highly complex nervous system, only part of which is localized in its brain, which is contained in a cartilaginous capsule.  Two-thirds of an octopus's neurons are found in the nerve cords of its arms, which show a variety of complex reflex actions that persist even when they have no input from the brain.  Unlike vertebrates, the complex motor skills of octopuses are not organized in their brain via an internal somatotopic map of its body, instead using a nonsomatotopic system unique to large-brained invertebrates.

 Nearly all octopuses are predatory; bottom-dwelling octopuses eat mainly crustaceans, polychaete worms, and other mollusks such as whelks and clams; open-ocean octopuses eat mainly prawns, fish and other cephalopods.  Major items in the diet of the giant Pacific octopus include bivalve mollusks such as the cockle Clinocardium nuttallii, clams and scallops and crustaceans such as crabs and spider crabs.  Prey that it is likely to reject include moon snails because they are too large and limpets, rock scallops, chitons and abalone, because they are too securely fixed to the rock.

 Intelligence

 Octopuses are highly intelligent; the extent of their intelligence and learning capability are not well defined.  Maze and problem-solving experiments have shown evidence of a memory system that can store both short- and long-term memory.  It is not known precisely what contribution learning makes to adult octopus behavior.  Young octopuses learn nothing from their parents, as adults provide no parental care beyond tending to their eggs until the young octopuses hatch.

 In laboratory experiments, octopuses can be readily trained to distinguish between different shapes and patterns.  They have been reported to practice observational learning, although the validity of these findings is contested.  Octopuses have also been observed in what has been described as play: repeatedly releasing bottles or toys into a circular current in their aquariums and then catching them.  Octopuses often break out of their aquariums and sometimes into others in search of food.  They have even boarded fishing boats and opened holds to eat crabs.  The veined octopus collects discarded coconut shells, then uses them to build a shelter, an example of tool use.

 Relationship to Humans

 Ancient seafaring people were aware of the octopus, as evidenced by certain artworks and designs. For example, a stone carving found in the archaeological recovery from Bronze Age Minoan Crete at Knossos (1900–1100 BC) has a depiction of a fisherman carrying an octopus. The terrifyingly powerful Gorgon of Greek mythology has been thought to have been inspired by the octopus or squid, the octopus itself representing the severed head of Medusa, the beak as the protruding tongue and fangs, and its tentacles as the snakes. The Kraken are legendary sea monsters of giant proportions said to dwell off the coasts of Norway and Greenland, usually portrayed in art as a giant octopus attacking ships. Linnaeus included it in the first edition of his 1735 Systema Naturae. One translation of the Hawaiian creation myth the Kumulipo suggests that the octopus is the lone survivor of a previous age. The Akkorokamui is a gigantic octopus-like monster from Ainu folklore.

 Japanese erotic art, shunga, includes ukiyo-e woodblock prints such as Katsushika Hokusai's 1814 print Tako to ama (The Dream of the Fisherman's Wife), in which an ama diver is sexually intertwined with a large and a small octopus. The print is a forerunner of tentacle erotica. The biologist P. Z. Myers noted in his science blog, Pharyngula, that octopuses appear in "extraordinary" graphic illustrations involving women, tentacles, and bare breasts. 

 Danger

 Octopuses generally avoid humans, but incidents have been verified. For example, a 2.4-metre (8 ft) Pacific octopus, said to be nearly perfectly camouflaged, "lunged" at a diver and "wrangled" over his camera before it let go.  Another diver recorded the encounter on video.

 All species are venomous, but only blue-ringed octopuses have venom that is lethal to humans.  Bites are reported each year across the animals' range from Australia to the eastern Indo-Pacific Ocean.  They bite only when provoked or accidentally stepped upon; bites are small and usually painless.  The venom appears to be able to penetrate the skin without a puncture, given prolonged contact.  It contains tetrodotoxin, which causes paralysis by blocking the transmission of nerve impulses to the muscles.  This causes death by respiratory failure leading to cerebral anoxia.  No antidote is known, but if breathing can be kept going artificially, patients recover within 24 hours.  Bites have been recorded from captive octopuses of other species; they leave swellings which disappear in a day or two.

 Fisheries and Cuisine

 Octopus fisheries exist around the world with total catches varying between 245,320 and 322,999 metric tons from 1986 to 1995.  The world catch peaked in 2007 at 380,000 tons, and fell by a tenth by 2012.  Methods to capture octopuses include pots, traps, trawls, snares, drift fishing, spearing, hooking and hand collection.  Octopus is eaten in many cultures and is a common food on the Mediterranean and Asian coasts.  The arms and sometimes other body parts are prepared in various ways, often varying by species or geography. Live octopuses are eaten in several countries around the world, including the US.  Animal welfare groups have objected to this practice on the basis that octopuses can experience pain.  Octopuses have a food conversion efficiency greater than that of chickens, making octopus aquaculture a possibility.

 Octopuses offer many possibilities in biological research, including their ability to regenerate limbs, change the colour of their skin, behave intelligently with a distributed nervous system, and make use of 168 kinds of protocadherins (humans have 58), the proteins that guide the connections neurons make with each other.  The California two-spot octopus has had its genome sequenced, allowing exploration of its molecular adaptations.  Having independently evolved mammal-like intelligence, octopuses have been compared to hypothetical intelligent extraterrestrials.  Their problem-solving skills, along with their mobility and lack of rigid structure enable them to escape from supposedly secure tanks in laboratories and public aquariums.

 Due to their intelligence, octopuses are listed in some countries as experimental animals on which surgery may not be performed without anesthesia, a protection usually extended only to vertebrates.  In the UK from 1993 to 2012, the common octopus (Octopus vulgaris) was the only invertebrate protected under the Animals (Scientific Procedures) Act 1986.  In 2012, this legislation was extended to include all cephalopods in accordance with a general EU directive.

 Some robotics research is exploring biomimicry of octopus features.  Octopus arms can move and sense largely autonomously without intervention from the animal's central nervous system.  In 2015 a team in Italy built soft-bodied robots able to crawl and swim, requiring only minimal computation.  In 2017 a German company made an arm with a soft pneumatically controlled silicone gripper fitted with two rows of suckers.  It is able to grasp objects such as a metal tube, a magazine, or a ball, and to fill a glass by pouring water from a bottle.

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