Spiracles are small openings on the surface of animals that usually lead to respiratory systems. Phyla Porifera (sponges) Ctenophora (comb jellies) Cnidaria Placozoa Bilateria Acoelomorpha Orthonectida Rhombozoa ?Myxozoa Superphylum Deuterostomia    Chordata (vertebrates, etc. ... The respiratory system is the biological system of any organism that engages in gas exchange. ...

In elasmobranchs (sharks, skates, and rays), a spiracle is found behind each eye, and is used to pump water through the gills while the animal is at rest (Fouts, 2003). Superorders Galeomorpha Batoidea Selachimorpha Elasmobranchii is the subclass of cartilaginous fishes that includes skates, rays and sharks. ... Orders see article text below Sharks are a group (superorder Selachimorpha) of fish, with a full cartilaginous skeleton, a streamlined body plan with between 5 and 7 gill slits along the sides (most often) or side of the head (the first modified slit is behind the eye and called a... This article is about the fish species. ... Ray has several meanings. ... Diagram of a human eye. ... A pump is a mechanical device used to move liquids or gases. ... In aquatic organisms, gills are a respiratory organ for the extraction of oxygen from water and for the excretion of carbon dioxide. ...

In insects and some more advanced spiders, spiracles allow air to enter trachea (Solomon et.al., 2002). However, unlike insects, tracheal tubes in spiders do not deliver oxygen to the animals tissues (Foelix, 1996). Instead the oxygen diffuses into the hemolymph (Foelix, 1996). Orders Subclass Apterygota Symphypleona - globular springtails Subclass Archaeognatha (jumping bristletails) Subclass Dicondylia Monura - extinct Thysanura (common bristletails) Subclass Pterygota Diaphanopteroidea - extinct Palaeodictyoptera - extinct Megasecoptera - extinct Archodonata - extinct Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Blattodea (cockroaches) Mantodea (mantids) Isoptera (termites) Zoraptera Grylloblattodea Dermaptera (earwigs) Plecoptera (stoneflies) Orthoptera (grasshoppers, crickets... Families Suborder Mesothelae     Liphistiidae (primitive burrowing spiders) Suborder Mygalomorphae     Atypidae (atypical tarantula)     Antrodiaetidae (folding trapdoor spider)     Mecicobothriidae (dwarf tarantulas)     Hexathelidae (venomous funnel-web tarantula)     Dipluridae (funnel-web tarantula)     Cyrtaucheniidae (wafer trapdoor spider)     Ctenizidae (trapdoor spider)     Theraphosidae (tarantula) Suborder Araneomorphae     Hypochilidae (lampshade spider)     Filistatidae (crevice weaver)     Sicariidae (recluse spider)     Scytodidae (spitting... The trachea (IPA treik-i-a), or windpipe, is a tube extending from the larynx to the bronchi in mammals, and from the pharynx to the syrinx in birds, carrying air to the lungs. ... General Name, Symbol, Number Oxygen, O, 8 Chemical series nonmetals Group, Period, Block 16 (VIA), 2, p Density, Hardness 1. ... A biological tissue is a group of biological cells that perform a similar function. ... Hemolymph (or haemolymph) is the blood analogue used by those animals, such as all arthropods and most mollusks, that have an open circulatory system. ...

References

• Fouts, William. April 2003. Marine Science Dept. Orange Coast College.
• Solomon, Eldra, Linda Berg, Diana Martin. 2002. Biology. Brooks/Cole.
• Foelix, Ranier. 1996. Biology of Spiders. Oxford U. Press