jawless fish

noun

1. cyclostome.

jawless fish

/ jô′lĭs /

1. Any of various primitive fish of the class Agnatha that lack jaws. Living jawless fish (lampreys and hagfish) have a long, cylindrical body and a cartilaginous skeleton. The numerous extinct species were often heavily armored and are among the earliest vertebrate fossils known. Jawless fish occupy an intermediate evolutionary position between primitive chordates and jawed fish.
2. Also called agnathan
3. See more at cyclostomeCompare bony fish

Word History and Origins

Origin of jawless fish¹

First recorded in 1965–70; jaw ¹ + -less