356 CYCLOSTOMES. 



to each other, or to the muzzle in front, and extend 

 backwards on both sides of the abdomen, nearly to 

 the base of the ventral fins. The eyes are placed 

 upon the back of the head. The mouth, the nostrils, 

 and the openings of the branchiae are on the ventral 

 surface of the body ; the dorsal fins are situated upon 

 the tail, which is very slender. Our coast furnishes 

 many species. 



To this family belong 



The Torpedos, or Electric Rays, celebrated for their power of 

 giving electric shocks. Their electric apparatus consists of a mul- 

 titude of vertical membranous tubes placed close together like the 

 cells of a honeycomb : these cells are filled with mucus and largely 



Fig, 29 J.— torpedo. 



supplied with nerves. The Torpedos are less powerfully 'electrical 

 than the Gymnoti, but can nevertheless benumb the arm of a per- 

 son 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 witli upon oui- southern coasts. 



Order of Cyclostomes, or Circular-mouthed 

 Chondropterygians. 



This, the last order of cartilaginous fishes, is 

 characterized by the singular conformation of the 

 mouth. Their body is elongated, naked, and slimy, 

 and they have neither pectoral nor ventral fins ; 

 such are 



The Lampreys {Petromyzon)* recognisable by seven 

 * irerpos, petros, a stone ; fiv^w, myzo, to suck. 



