I04 



A HISTORY OF FISHES 



no means uncommon for one of these pests to steal a ride on a 

 Salmon or other fish when it wishes to ascend a river for 

 spawning purposes. The sucking mouth is also used to anchor 

 it to stones on the river bed, and it is of interest to note that the 

 name Lamprey refers to this habit, being derived from the 



Fig. 45. — INFERIOR AND SUCTORIAL MOUTHS. 



A. Opened mouth of the Sea Lamprey (Petromyzon marinus)^ X 3 ; b. Lower 



surface of head of Spotted Dog-fish (Scyliorhinus caniculus), x ^ ; c. The same 



of Sturgeon (Acipenser rubicundus), X ^ ; d. The same of Mailed Cat-fish 



(Plecostomus guacari), X 5. 



mediaeval Latin Lafupreda, a corruption of the older Lampetra, 

 from lambere, to lick, and petra, a stone. In the Hag-fishes 

 {Myxinidae) there is no distinct funnel, and the almost terminal 

 mouth is surrounded by short barbules or tentacles. 



Among the existing Sharks the mouth is nearly always 

 crescentic in shape, and placed on the under side of the head 



