I. -ˈäksəs
Etymology: New Latin, irregular from amphi- + Greek oxys sharp
synonym of branchiostoma
II. noun
( plural amphi·oxi -ˈäkˌsī ; or amphioxuses )
: a lancelet of the genus Branchiostoma, typically being a small transparent marine animal pointed at both ends, having an oral opening just below the anterior end surrounded by cirri, dorsal and anal fins but no limbs, a notochord, a dorsally situated nerve cord but no definite brain, a system of blood vessels but no heart, eyes represented by a medium pigment spot, and an olfactory but no auditory organ