amphioxus vs lancelet

amphioxus and lancelet both are nouns.

Word	Noun	Adjective	Verb	Adverb
amphioxus	Yes	No	No	No
lancelet	Yes	No	No	No

As nouns, amphioxus and lancelet are synonyms defined as:

amphioxus and lancelet: small translucent lancet-shaped burrowing marine animal; primitive forerunner of the vertebrates

amphioxus (noun)	lancelet (noun)
small translucent lancet-shaped burrowing marine animal; primitive forerunner of the vertebrates	small translucent lancet-shaped burrowing marine animal; primitive forerunner of the vertebrates