1) Fish genus 2) Genus petromyzon 3) Typical lampreys 
Primitive marine vertebrate (Class Agnatha) with eel like body and lacking true jaws. Their relatively simple nervous system has been studied in some detail. ... (18 Nov 1997) ... 
(= lamprey) Primitive marine vertebrate (Class Agnatha) with eel-like body and lacking true jaws. Their relatively simple nervous system has been studied in some detail.
[n] - typical lampreys
genus Petromyzon noun typical lampreys