An animal in which the opening (blastopore) of the embryonic cavity (see archenteron) becomes the anus and the mouth forms as a secondary orifice. The name derives from Greek, meaning literally ‘second mouth’. Deuterostomes comprise one of the two main subkingdoms of animals (Deuterostomia), the other being the Protostomia (see protostome). Deuterostomes typically display radial cleavage of the blastula, indeterminate development (the fate of cells is not established until later stages of development), and enterocoelic formation of the coelom (i.e. by outpocketing of the embryonic gut). The three deuterostome phyla are the Hemichordata, Echinodermata, and Chordata.
Subjects: Biological Sciences.