Invertebrates

Animals without a backbone or spinal column, including all soft-bodied animals without a rigid internal skeleton for the attachment of muscles, but often with a hard outer skeleton, comprising the great majority of all animals (such as insects, mollusks, and crustaceans). Apart from the absence of a vertebral column, invertebrates have little in common. The taxonomic term Invertebrata, formerly used in contrast to Vertebrata (still a valid subphylum name), is not used in modern classifications.