58 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



9. There is only one row of large thorns along the midzone of the disc from the nape to the level of the axils of the pectoral 



fins; the first and second dorsal fins are separated by a definite space or at least by 1 or 2 thorns; the forward angle 

 of the disc is less than 110°; the upper surface of the disc is marked with short dark bars as well as with roundish 



spots. _ - Brier skate, p. 65 



There are at least three rows of thorns along the midzone of the disc from the nape to the level of the axils of the 

 pectoral fins; the first and second dorsal fins are not separated by a definite interspace or by a thorn or thorns; the 

 forward angle of the disc is more than 125°; the upper surface is not marked with dark bars though it is variously 

 spotted 10 



10. Upper teeth in at least 72 series, most often 90-100; does not mature sexually until at least 26 inches long. 



Big skate, p. 63 

 Upper teeth in not more than 66 series and usually less then 54; matures when only 18-20 inches long. 



Little skate, p. 67 



11. There is a small dorsal fin on the upper side of the tail, in front of the spine (or spines) ; the crown of the head is high- 



domed, with the eyes and spiracles on the sides; there are only 7-9 series of teeth in the form of large flat grinding 



plates _ Cow nosed ray, p. 76 



There is no dorsal fin on the tail; the crown is low, flat, and with the eyes and spiracles on the upper surface; the 

 teeth are in many series, in mosaic arrangement Sting ray, p. 74 



THE TORPEDOES OR ELECTRIC RAYS. FAMILY TORPEDINIDAE 



The trunk of the electric rays has the form of a 

 flattened, roundish or oval disc, fleshier toward 

 the margins than it is in other Gulf of Maine 

 skates or rays, and the body is softer. The tail, 

 too, is broader and shorter; there are one or two 

 relatively larger dorsal fins on the tail, and the 

 latter ends in a well -developed caudal fin also. 



The most interesting feature of the electric rays 

 is that they have two large electric organs, each 

 of which occupies one side of the front part of the 



disc. In the only Gulf of Maine species the two 

 organs together make up about one-sixth of the 

 total weight of the fish. 



Torpedo Torpedo nobiliana Bonaparte 1835 



Electric rat; Numbfish, Crampfish 



Bigelow and Schroeder, 1953, p. 96. 



Carman, 1913, pi. 25, fig. 2, as Narcacion nobilianus. 



Description. — No one would be apt to mistake a 



Figure 24. — Torpedo (Torpedo nobiliana), male, about 33 inches long, off Plymouth, Massachusetts. A, side view of 

 caudal fin; B, teeth 3 times natural size. From Bigelow and Schroeder. Drawings by E. N. Fischer. 



