Editing Anatomy (section)

=== Arthropod anatomy ===
{{main|Arthropod|Insect morphology|Spider anatomy}}
[[Arthropod]]s comprise the largest phylum of [[invertebrate]]s in the animal kingdom with over a million known species.<ref>Britannica Concise Encyclopaedia 2007</ref>

[[Insect]]s possess [[segmentation (biology)|segmented]] bodies supported by a hard-jointed outer covering, the [[exoskeleton]], made mostly of [[chitin]]. The segments of the body are organized into three distinct parts, a head, a [[Thorax (insect anatomy)|thorax]] and an [[abdomen]].<ref>{{cite web|title=O. Orkin Insect zoo |url=https://insectzoo.msstate.edu/Students/basic.structure.html |year=1997 |publisher=Mississippi State University |access-date=23 June 2013 |url-status=dead |archive-url=https://web.archive.org/web/20090602045832/https://www.insectzoo.msstate.edu/Students/basic.structure.html |archive-date=2 June 2009 }}</ref> The head typically bears a pair of sensory [[Antenna (biology)|antennae]], a pair of [[compound eye]]s, one to three simple eyes ([[ocelli]]) and three sets of modified appendages that form the [[insect mouthparts|mouthparts]]. The thorax has three pairs of segmented [[arthropod leg|legs]], one pair each for the three segments that compose the thorax and one or two pairs of [[insect wing|wings]]. The abdomen is composed of eleven segments, some of which may be fused and houses the [[digestion|digestive]], [[Respiration (physiology)|respiratory]], [[excretory]] and reproductive systems.<ref name="Gullan and Cranston">{{cite book |last1=Gullan |first1=P.J. |last2=Cranston |first2=P. S. |title=The Insects: An Outline of Entomology |publisher=Blackwell Publishing |location=Oxford |year=2005 |edition=3 |pages=[https://archive.org/details/isbn_9781405111133/page/22 22–48] |isbn=978-1-4051-1113-3 |url-access=registration |url=https://archive.org/details/isbn_9781405111133/page/22 }}</ref> There is considerable variation between species and many adaptations to the body parts, especially wings, legs, antennae and mouthparts.<ref>{{cite book |title=Invertebrate Zoology, 7th edition |last1=Ruppert |first1=Edward E. |last2=Fox |first2=Richard, S. |last3=Barnes |first3=Robert D. |year=2004 |publisher=Cengage Learning |isbn=978-81-315-0104-7 |pages=218–225 }}</ref>

[[Spider]]s a class of [[arachnid]]s have four pairs of legs; a body of two segments—a [[cephalothorax]] and an [[abdomen]]. Spiders have no wings and no antennae. They have mouthparts called [[chelicerae]] which are often connected to venom glands as most spiders are venomous. They have a second pair of appendages called [[pedipalp]]s attached to the cephalothorax. These have similar segmentation to the legs and function as taste and smell organs. At the end of each male pedipalp is a spoon-shaped cymbium that acts to support the [[palpal bulb|copulatory organ]].