- The lancelets, the typical genus of the family <em>Amphioxidæ</em>, whose body is compressed and tapers to a point at each end: a synonym of <em>Branchiostoma</em> (which see). See also cut under <internalXref urlencoded="lancelet">lancelet</internalXref>.
- A fishlike creature (<spn>Amphioxus lanceolatus</spn>), two or three inches long, found in temperature seas; -- also called the <altname>lancelet</altname>. Its body is pointed at both ends. It is the lowest and most generalized of the vertebrates, having neither brain, skull, vertebræ, nor red blood. It forms the type of the group <ex>Acrania</ex>, <ex>Leptocardia</ex>, etc.
- The <xref>lancelet</xref>
- small translucent lancet-shaped burrowing marine animal; primitive forerunner of the vertebrates