Spider web Silver Pendant Charm GOOD LUCK ~ LUCKY SYMBOL GOTHIC Necklace Antique

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Spider web Silver Pendant Charm GOOD LUCK ~ LUCKY SYMBOL GOTHIC Necklace Antique:
$0.99

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The discount is regular shipping price for the first item and just 50 cents for each additional item!
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Hi there, I am selling everything in my world. I need desperately to raise money.
I just found out termites were eating my house. I have a lot of things that I don\'t need.
I thought it would be a good time to downsize my world, and hopefully make some money to buy new walls.
This is a Spider or arachnid pendant. It is silver metal, although, probably not real sterling silver . I got this at an estate sale.
This estate sale was of a jewelry designer, and she had pearls, made jewelry, half made jewelry, and tons of beads and charms.
There was gold wire, and silver wire, and findings to make earrings, and necklaces, it was really cool!
I have been making plans to make something out of all these great finds that I got in her treasure trove, but I don\'t think I will ever get around to it.
I need to raise some money, so I will just sell a lot of the great things I got there for now, and I am sure they will come back around.
It measures 35 mm by 25 mm by 3 mm and weighs 17.15 carats, which is 3.42 grams
I love it , but I need to make money, so there you go - , cheap shipping, starting offer FOR ALL OF THEM under a buck!!!
Can\'t beat it!
I will put a Wikipedia entry about this below.
If you have anymore questions, just ask. I am sure I am leaving something out.
Arachnid From Wikipedia, the free encyclopedia Jump to: navigation, search For other uses, see Arachnid (disambiguation).\"Arachnida\" redirects here. For the arachnida curve, see Sectrix of Maclaurin.Arachnida
Fossil range: 420–0MaPreЄЄOSDCPTJKPgNSilurian to Recent[1]\"Arachnida\" from Ernst Haeckel\'s Kunstformen der Natur, 1904Scientific 1812Extant are a class (Arachnida) of joint-legged invertebrate animals in the subphylum Chelicerata. All arachnids have eight legs, although in some species the front pair may convert to a sensory function. The term is derived from the Greek word ἀράχνη (aráchnē), meaning \"spider\".[2]

Almost all arachnids are terrestrial. However, some inhabit freshwater Environments and, with the exception of the pelagic zone, marine Environments as well. They comprise over 100,000 named species, including spiders, scorpions, harvestmen, ticks, mites and Solifugae.[3]

Contents [hide]

• 1 Anatomy
• 2 Physiology
• 3 Diet and digestive system
• 4 Senses
• 5 Reproduction
• 6 Systematics
  • 6.1 Acarina
  • 6.2 Amblypygi
  • 6.3 Araneae
  • 6.4 Haptopoda
  • 6.5 Opiliones
  • 6.6 Palpigradi
  • 6.7 Phalangiotaroffera
  • 6.8 Pseudoscorpions
  • 6.9 Ricinulei
  • 6.10 Schizomida
  • 6.11 Scorpions
  • 6.12 Solifugae
  • 6.13 Trigonotaroffera
  • 6.14 Thelyphonida
• 7 References
• 8 See also
• 9 External links

AnatomyBasic characteristics of arachnids include four pairs of legs (1) and a body divided into two segments: the cephalothorax (2) and the abdomen (3).

Almost all adult arachnids have eight legs, and arachnids may be easily distinguished from insects by this fact, since insects have six legs. However, arachnids also have two further pairs of appendages that have become adapted for feeding, defense, and sensory perception. The first pair, the chelicerae, serve in feeding and defense. The next pair of appendages, the pedipalps have been adapted for feeding, locomotion, and/or reproductive functions. In Solifugae, the palps are quite leg-like, so that these animals appear to have ten legs. The larvae of mites and Ricinulei have only six legs; the fourth pair appears when they moult into nymphs. However, there are also adult mites with six, or even four legs.[4]

Arachnids are further distinguished from insects by the fact they have no antennae or wings. Their body is organized into two tagma called the prosoma, or cephalothorax, and the opisthosoma, or abdomen. The cephalothorax is derived from the fusion of the cephalon (head) and the thorax, and is usually covered by a single, unsegmented carapace. The abdomen is segmented in the more primitive forms, but varying degrees of fusion between the segments occur in many groups. It is typically divided into a preabdomen and postabdomen, although this is only clearly visible in scorpions, and in some orders, such as the Acari, the abdominal sections are completely fused.[5]

Like all arthropods, arachnids have an exoskeleton, and they also have an internal structure of cartilage-like tissue called the endosternite, to which certain muscle groups are attached. The endosternite is even calcified in some Opiliones.[6]

Physiology

There are some characteristics that are particularly important for the terrestrial lifestyle of an arachnid, such as internal respiratory surfaces in the form of tracheae, or modification of the book gill into a book lung, an internal series of vascular lamellae used for gas exchange with the air. While the tracheae are often individual systems of tubes, similar to those in insects, ricnuleids, pseudoscorpions, and some spiders possess sieve tracheae, in which several tubes arise in a bundle from a small chamber connected to the spiracle. This type of tracheal system has almost certainly evolved from the book lungs, and indicates that the tracheae of arachnids are not homologous with those of insects.[7]

Further adaptations to terrestrial life are appendages modified for more efficient locomotion on land, internal fertilisation, special sensory organs, and water conservation enhanced by efficient excretory structures as well as a waxy layer covering the cuticle.

The excretory glands of arachnids include up to four pairs of coxal glands along the side of the prosoma, and one or two pairs of Malpighian tubules, emptying into the gut. Many arachnids have only one or the other type of excretory gland, although several do have both. The primary nitrogenous waste product in arachnids is guanine.[7]

The blood of arachnids is variable in composition, depending on the mode of respiration. Arachnids with an efficient tracheal system do not need to transport oxygen in the blood, and may have a reduced circulatory system. In scorpions and some spiders, however, the blood contains haemocyanin, a copper-based pigment with a similar function to haemoglobin in vertebrates. The heart is located in the forward part of the abdomen, and may or may not be segmented. Some mites have no heart at all.[7]

Diet and digestive system

Arachnids are mostly carnivorous, feeding on the pre-digested bodies of insects and other small animals. Only in the harvestmen and among mites, such as the house dust mite, is there ingestion of solid food particles, and thus exposure to internal parasites,[8] although it is not unusual for spiders to eat their own silk. Several groups secrete venom from specialized glands to kill prey or enemies. Several mites are parasites, some of which are carriers of disease.

Arachnids pour digestive juices produced in their stomachs over their prey after killing it with their pedipalps and chelicerae. The digestive juices rapidly turn the prey into a broth of nutrients which the arachnid sucks into a pre-buccal cavity located immediately in front of the mouth. Behind the mouth is a muscular, sclerotised pharynx, which acts as a pump, sucking the food through the mouth and on into the oesophagus and stomach. In some arachnids, the oesophagus also acts as an additional pump.

The stomach is tubular in shape, with multiple diverticula extending throughout the body. The stomach and its diverticula both produce digestive enzymes and absorb nutrients from the food. It extends through most of the body, and connects to a short sclerotised intestine and anus in the hind part of the abdomen.[7]

Senses

Arachnids have two kinds of eyes, the lateral and median ocelli. The lateral ocelli evolved from compound eyes and may have a tapetum, which enhances the ability to collect light. The median ocelli develop from a transverse fold of the ectoderm. The ancestors of modern arachnids probably had both types, but modern ones often lack one type or the other.[8] The cornea of the eye also acts as a lens, and is continuous with the cuticle of the body. Beneath this is a transparent vitreous body, and then the retina and, if present, the tapetum. In most arachnids, the retina probably does not have enough light sensitive cells to allow the eyes to form a proper image.[7]

In addition to the eyes, almost all arachnids have two other types of sensory organs. The most important to most arachnids are the fine sensory hairs that cover the body and give the animal its sense of touch. These can be relatively simple, but many arachnids also possess more complex structures, called trichobothria.

Finally, slit sense organs are slit-like pits covered with a thin membrane. Inside the pit, a small hair touches the underside of the membrane, and detects its motion. Slit sense organs are believed to be involved in proprioception, and possibly also hearing.[7]

Reproduction

Arachnids may have one or two gonads, which are located in the abdomen. The genital opening is usually located on the underside of the second abdominal segment. In most species, the male transfers sperm to the female in a package, or spermatophore. Complex courtship rituals have evolved in many arachnids to ensure the safe delivery of the sperm to the female.[7]

Arachnids usually lay yolky eggs, which hatch into immatures that resemble adults. Scorpions, however, are either ovoviviparous or viviparous, depending on species, and bear live young.

Systematics

• † Trigonotaroffera — extinct
• Amblypygi — \"blunt rump\" tailless whip scorpions with front legs modified into whip-like sensory structures as long as 25cm or more (140 of the Chelicerata
  (after Giribet et al. 2002)
  • Araneae — true spiders (40,000 species)
    • Mesothelae — very rare, basal spiders, with abdomen segmented and spinnerets median
    • Opisthothelae — spiders with abdomen unsegmented and spinnerets located posteriorly
      • Araneomorphae — most common spiders
      • Mygalomorphae — tarantulas and tarantula-like spiders
  • † Phalangiotaroffera — extinct
  • Opiliones — phalangids, harvestmen or daddy-long-legs (6,300 species)
  • Palpigradi — microwhip scorpions (80 species)
  • Pseudoscorpionida — pseudoscorpions (3,000 species)
  • Ricinulei — ricinuleids, hooded tickspiders (60 species)
  • Schizomida — \"split middle\" whip scorpions with divided exoskeletons (220 species)
  • Scorpiones — scorpions (2,000 species)
  • Solifugae — solpugids, windscorpions, sun spiders or camel spiders (900 species)
  • † Haptopoda — extinct
  • Thelyphonida — vinegarroons or whip scorpions (formerly uropygida) forelegs modified into sensory appendages and a long tail on abdomen tip (100 species)
  • Acarina — mites and ticks (30,000 — holothyrans, ticks and mesostigmatic mites

It is estimated that a total of 98,000 arachnid species have been described, and that there may be up to 600,000 in total, including undescribed species.[9]

AcarinaIxodes hexagonus, a tickMain article: Acarina

Acarina or Acari are a taxon of arachnids that contains mites and ticks. Its fossil history goes back to the Devonian era, although there is also a questionable Ordovician record. The Devonian era was the time frame in which certain species of animals developed legs. In most modern treatments, the Acari is considered a subclass of Arachnida and is composed of 2–3 orders or superorders: Acariformes, Parasitiformes, and Opilioacariformes. Most acarines are minute to small (e.g. 0.080–1.00mm), but the giants of the Acari (some ticks and red velvet mites) may reach lengths of 10–20mm. It is estimated that over 50,000 species have been described (as of 1999) and that a million or more species are currently living. The study of mites and ticks is called acarology.[10]

Only the faintest traces of primary segmentation remain in mites, the prosoma and opisthosoma being insensibly fused, and a region of flexible cuticle (the cirumcapitular furrow) separates the chelicerae and pedipalps from the rest of the body. This anterior body region is called the capitulum or gnathosoma and is also found in the Ricinulei. The remainder of the body is called the idiosoma and is unique to mites. Most adult mites have four pairs of legs, like other arachnids, but some have fewer. For example, gall mites like Phyllocoptes variabilis (superfamily Eriophyioidea) have a wormlike body with only two pairs of legs; some parasitic mites have only one or three pairs of legs in the adult stage. Larval and prelarval stages have a maximum of three pairs of legs; adult mites with only three pairs of legs may be called \'larviform\'.

Acarine ontogeny consists of an egg, a prelarval stage (often absent), a larval stage (hexapod except in Eriophyoidea, which have only 2 pairs of legs), and a series of nymphal stages. Larvae (and prelarvae) have a maximum of 3 pairs of legs (legs are often reduced to stubs or absent in prelarvae); legs IV are added at the first nymphal stage.

Acarines live in practically every habitat, and include aquatic (freshwater and sea water) and terrestrial species. They outnumber other arthropods in the soil organic matter and detritus. Many are parasitic, and they affect both vertebrates and invertebrates. Most parasitic forms are external parasites, while the free living forms are generally predaceous and may even be used to control undesirable arthropods. Others are detritivores that help to break down forest litter and dead organic matter such as skin cells. Others still are plant feeders and may damage crops. Damage to crops is perhaps the most costly economic effect of mites, especially by the spider mites and their relatives (Tetranychoidea), earth mites (Penthaleidae), thread-footed mites (Tarsonemidae) and the gall and rust mites (Eriophyoidea). Some parasitic forms affect humans and other mammals, causing damage by their feeding, and can even be vectors of diseases such as scrub typhus and rickettsial pox. A well-known effect of mites on humans is their role as an allergen and the stimulation of asthma in people affected by the respiratory disease. The use of predatory mites (e.g. Phytoseiidae) in pest control and herbivorous mites that attack weeds are also of importance. An unquantified, but major positive contribution of the Acari is their normal functioning in ecosystems, especially their roles in the decomposer subsystem.[10]

AmblypygiAn amblypygidMain article: Amblypygi

Amblypygids are also known as tailless whip scorpions or cave spiders. Approximately 5 families, 17 genera and 136 species have been described. They are found in tropical and subtropical regions worldwide. Some species are subterranean; many are nocturnal. During the day, they may hide under logs, bark, stones, or leaves. They prefer a humid Environment. Amblypygids may range from 5 to 40mm. Their bodies are broad and highly flattened and the first pair of legs (the first walking legs in most arachnid orders) are modified to act as sensory organs. (Compare solifugids, uropygids, and schizomids.) These very thin modified legs can extend several times the length of body. They have no silk glands or venomous fangs, but can have prominent pincer-like pedipalps. Amblypygids often move about sideways on their six walking legs, with one \"whip\" pointed in the direction of travel while the other probes on either side of them. Prey are located with these \"whips\", captured with pedipalps, then torn to pieces with chelicerae. Fossilised amblypygids have been found dating back to the Carboniferous period.

Amblypygids, particularly the species Phrynus marginemaculatus and Damon diadema, are thought to be one of the few species of arachnids that show signs of social behavior. Research conducted at Cornell University by entomologists suggests that mother amblypygids comfort their young by gently caressing the offspring with her feelers. Further, when two or more siblings were placed in an unfamiliar Environment, such as a cage, they would seek each other out and gather back in a group.[11]

AraneaeAraneus diadematusMain article: spider

Araneae, or spiders, are the most familiar of the arachnids, and the most numerous, if only described species are counted. All spiders produce silk, a thin, strong protein strand extruded by the spider from spinnerets most commonly found on the end of the abdomen. Many species use it to trap insects in webs, although there are many species that hunt freely. Silk can be used to aid in climbing, form smooth walls for burrows, build egg sacs, wrap prey, temporarily hold sperm, and even fly, among other applications.

All spiders except those in the families Uloboridae and Holarchaeidae, and in the suborder Mesothelae (together about 350 species) can inject venom to protect themselves or to kill and liquefy prey. Only about 200 species, however, have bites that can pose health problems to humans.[12] Many larger species\' bites may be painful, but will not produce lasting health concerns.

Spiders are found all over the world, from the tropics to the Arctic, with some extreme species even living underwater in silken domes that they supply with air,[13] and on the tops of the highest mountains.

HaptopodaMain article: Haptopoda

Haptopoda is an extinct order known exclusively from a few specimens from the Upper Carboniferous of the United Kingdom. It is monotypic, i.e. has only one species: Plesiosiro madeleyi Pocock 1911. Relationships with other arachnids are obscure, but closest relatives may be the Amblypygi, Thelyphonida and Schizomida of the tetrapulmonate clade.[14]

OpilionesParoligolophus agrestisMain article: Opiliones

Opiliones (better known as \"harvestmen\" or \"daddy longlegs\") are arachnids that are harmless to people and are known for their exceptionally long walking legs, compared to their body size. As of 2005, over 6,300 species of Phalangids have been discovered worldwide. The order Opiliones can be divided in four suborders: Cyphophthalmi, Eupnoi, Dyspnoi and Laniatores. Well-preserved fossils have been found in the 410-million year old Rhynie cherts of Scotland, which look surprisingly modern, indicating that the basic structure of the harvestmen hasn\'t changed much since then.

The difference between harvestmen and spiders is that in harvestmen the two main body sections (the abdomen with ten segments and cephalothorax, or prosoma and opisthosoma) are nearly joined, so that they appear to be one oval structure. In more advanced species, the first five abdominal segments are often fused into a dorsal shield called the scutum, which is normally fused with the carapace. Sometimes this shield is only present in males. The two most posterior abdominal segments can be reduced or separated in the middle on the surface to form two plates lying next to each other. The second pair of legs are longer than the others and works as antennae. They have a single pair of eyes in the middle of their heads, orientated sideways. They have a pair of prosomatic scent glands that secrete a peculiar smelling fluid when disturbed. Harvestmen do not have silk glands and do not possess poison glands, posing absolutely no danger to humans. They breathe through tracheae. Between the base of the fourth pair of legs and the abdomen a pair of spiracles are located, one opening on each side. In more active species, spiracles are also found upon the tibia of the legs. They have a gonopore on the ventral cephalothorax, and the copulation is direct as the male has a penis (while the female has an ovipositor).

Typical body length does not exceed 7mm (about ¼in) even in the largest species. However, leg span is much larger and can exceed 160mm (over 6in). Most species live for a year. Many species are omnivorous, eating primarily small insects and all kinds of plant material and fungi; some are scavengers of the decays of any dead animal, bird dung and other fecal material. They are mostly nocturnal and coloured in hues of brown, although there are a number of diurnal species that have vivid patterns in yellow, green and black with varied reddish and blackish mottling and reticulation.

PalpigradiMain article: Palpigradi

Palpigradi, commonly known as \"microwhip scorpions\", are tiny cousins of the uropygid, or whip scorpion, no more than 3mm in length. They have a thin, pale, segmented carapace that terminates in a whip-like Flagellum, made up of 15 segments. The carapace is divided into two plates between the third and fourth leg set. They have no eyes. Some species have three pairs of book lungs, while others have no respiratory organs at all.[15] Approximately 80 species of Palpigradi have been described worldwide, in the families Eukoeneniidae and Prokoeneniidae, with a total of seven genera.

They are believed to be predators like their larger relatives, feeding on minuscule insects in their habitat. Their mating habits are unknown, except that they lay only a few relatively large eggs at a time. Microwhip scorpions need a damp Environment to survive, and they always hide from light, so they are commonly found in the moist earth under buried stones and rocks. They can be found on every continent, except in Arctic and Antarctic regions.

PhalangiotarofferaMain article: Phalangiotaroffera

Phalangiotarbi (Haase, 1890) is an extinct arachnid order known exclusively from the Palaeozoic (Devonian to Permian) of Europe and North America.

The affinities of phalangiotaroffers are obscure, with most authors favouring affinities with Opiliones (harvestmen) and/or Acari (mites and ticks). Phalangiotaroffera has been recently proposed to be sister group to (Palpigradi+Tetrapulmonata): the taxon Megoperculata sensu Shultz (1990). (Pollitt et al., 2004).

Pseudoscorpions

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Spider web Silver Pendant Charm GOOD LUCK ~ LUCKY SYMBOL GOTHIC Necklace Antique:
$0.99