LAMPREYS. 



269 



membranous tubes placed close together like the cells of a honeycomb : the 

 cells are filled with mucus and largely supplied with nerves. The torpedos 

 are less powerfully electrical than the Gymnoti, but can nevertheless benumb 

 the arm of a person touching them, hence they are called Cramp- Fishes. They 

 probably use their electrical batteries as a means of obtaining their prey. They 

 are frequently met with upon our southern coasts. 



SUB-ORDER OF CYCLOSTOMES. 



This sub-order of cartilaginous fishes is characterized by the 

 singular conformation of the mouth, which is circular and adapted 

 for suction. Their body is elongated, naked, and slimy, and they 

 have neither pectoral nor ventral fins ; such are 



The Lampreys (Petromyzon),* recognizable by seven branchial openings 

 placed on each side of the neck, and by their circular mouth, armed with 

 several ranges of strong teeth ; the tongue is also furnished with teeth, and is 

 carriedfforward and backward like a piston, thus enabling the animal to use 

 its mouth not only to suck in the materials upon which it feeds, but to attach 

 itself to solid bodies. The skin of these fishes above and below the tail is 

 raised into a vertical crest, which takes the place of fins. 



FIG. 291. I^AMPREV. 



The Sea-Lamprey (Petromyson mar inns] is two or three feet long, and marbled 

 with brown on a yellowish ground. It inhabits the coasts both of Europe and America, 

 and in the spring ascends rivers to deposit its eggs. It ordinarily preys upon marine 

 Mollusca or fragments of dead animals ; but it also attaches itself to large fishes, and 

 succeeds in piercing their skin and destroying them. I:s flesh is much esteemed. 



FIG. 292. RIVER-LAMPREY. 



The Fresh-Water or River-Lamprey (Pdromyzon flirciatilis] is a smaller 

 species, seldom exceeding eighteen inches in length ; it passes the greater part of the 



* Tre'rpos, petros, a stone ; /4i5fw, myzo, to suck. 



