38 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



45. R. productus Ayres. 



" The anterior nasal valve is dilated into a very narrow lateral fold, 

 scarcely projecting- beyond the nasal margin. The length of the nostril 

 is slightly more than its distance from the lateral margin of the head 

 and more than the distance between the inner angles of the nostrils, and 

 much less than the width of the mouth, which is very slightly arched. 

 Snout produced, the distance between the outer angles of the nostrils 

 being f of that between the mouth and the end of the snout. A series 

 of small, depressed, polished spines along the median ridge of the back ; 

 groups of small, polished tubercles on the orbital margin and on the 

 shoulder. A broad groove between the rostral ridges, which are sepa- 

 rated along their entire length. Snout lighter colored than the rest of 

 the body." — (Streets.) Coast of California and southward. 



(Ayres MSS.; Girard, Proc. Ac. Nat. Sci. Phila. 1854, 196; Streets, Ball. U. S. Nat. 

 Mus, vii, 1877, 55: Bhinobains leucorhynchns Giiuther, viii, 444.) 



Super-family TORPEDINOIDEA. 



s 



{The Torpedinoid Bays.) 



Family XIX.— TORPEDINID^. 



{The JSfumh-Jishes.) 



Rays with the trunk broad and smooth ; the tail comparatively short 

 and thick, with rayed caudal lin, and commonly two rayed dorsal fins 

 the iirst of which is over or behind tlie ventrals ; a longitudinal fold on each 

 side of tail ; anterior nasal valves confluent into a quadrangular lobe ; 

 an electric organ composed of hexagonal tubes between the pectoral 

 tins and the head. Genera 6 ; species about 15 ; large rays, noted for 

 their jiower of giving electric shocks ; found in most seas, ( Torpedinidce 

 Giinther, viii, 448-455.) 



*Unisal tins two; ventrals separate; spiraeJes well behind the eyes TORPEDO, 30. 



36.— TORPEDO Dnmdril, 1800. 

 Electric Bays. 



(Dum^.ril, Zool. Analyt. p. 102: tyite Ihtid torpedo L.) 



Electric rays with the disk very broad, abruptly contracted at the 

 tail ; two dorsal tins ; caudal fin well developed ; ventral fins large, sepa- 

 rate; spiracles large, placed behind the eyes; mouth small; teeth pointed; 

 skin perfectly smooth. Large rays, chiefly inhabiting the Atlanti(5. 



