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An '''invertebrate''' (in contrast to a [[vertebrate]]), is an [[animal]] with no [[spine]].  Most living things are invertebrates, including [[arthropod]]s, [[mollusc]]s, and [[bacteria]].

An '''invertebrate''' (in contrast to a [[vertebrate]]), is an [[animal]] with no [[spine]].  Most living things are invertebrates, including [[arthropod]]s, [[mollusc]]s, and [[bacteria]].

[[Shark]]s and [[ray]]s are a special class under this description, since they do not have bony [[skeleton]]s, and hence no spine.  They do, however, have a similar structure to vertebrates.  They are called [[notochord]]s.

[[Shark]]s and [[sting ray|rays]] are a special class under this description, since they do not have bony [[skeleton]]s, and hence no spine.  They do, however, have a similar structure to vertebrates.  They are called [[notochord]]s.

The phyla contained in Invertebrata are:

The phyla contained in Invertebrata are: