any one of various tiny, flattened marine organisms of subphylum Cephalochordata, structurally similar to the vertebrates but having a notochord as opposed to a true vertebral line. Also called amphioxus.
some of a team of primitive marine creatures, of subphylum Cephalochordata, having a notochord in the place of a backbone
a little fishlike pet (Amphioxus lanceolatus), remarkable when it comes to rudimentary condition of their body organs. It is the particular the course Leptocardia. See amphioxus, leptocardia.
The sand-lance, amphioxns, or branchiostome, a skull-less fish-like vertebrate, representing a genus Branchiostoma or Ámphioxus, a household Branchiostomidæ or Á mphioxidæ, an order Pharyngobranchii, a class Leptocardii, and a ‘branch’ of vertebrates lately called Cephalochorda. See these brands, and Acrania.
small translucent lancet-shaped burrowing marine pet; ancient forerunner for the vertebrates