FISHES OF THE GULF OF MAINE 



57 



Color. — Described as dark gray, olive or brown 

 above, with metallic reflections, and with or 

 witbout darker blotches; as paler brown or gray 

 to white below. The scales have been described 

 as luminescent, 64 but there are no special luminous 

 organs. 



Size. — The largest of which we have found a 

 record (a specimen from British waters) was 9 

 feet long. One 8 feet 4 inches long weighed about 

 .300 pounds. 



General, range. — Eastern Atlantic (including the 

 Mediterranean) from tropical West Africa to 



Ireland and the North Sea, and accidental in the 

 western Atlantic; represented in South Africa; 

 off California; in the Hawaiian, Japanese, and 

 Australo-New Zealand regions, and in Arabian 

 waters by forms that probably cannot be dis- 

 tinguished from brucus of the Atlantic. 



Occurrena in the Gulf oj Maim. A single 

 specimen of this little known shark came ashore 

 at Provincetown in December 1878. This and 

 one taken near Buenos Aires more recently 5S 

 are the onlv records of it from the western Atlantic. 



Torpedoes, Skates, and Rays. Order Batoidei 



This tribe falls into four groups, so far as the 

 Gulf of Maine fauna is concerned: first, the 

 torpedoes (family Torpedinidae) , with large caudal 

 fin, interesting because provided with electric 

 organs capable of giving a strong shock; second, 

 the skates (family Rajidae), with very thin bodies, 

 comparatively short tails without tail spines, and 

 only a trace of caudal fin; third, the sting rays 

 (families Dasyatidae and Rhinopteridae), with 

 long whiplike tails armed with a stiff saw-edged 

 spine (or spines); and fourth, the devil rays 



•< Cornish, Zoologist, Sor. 2, vol. 10, 187S, p. 4501. 



(Mobulidae) with two ear-like fins extending 

 forward from the front of the head. Most of our 

 common species belong to the second group. 



Among torpedoes, skates, and rays, fertiliza- 

 tion is internal as it is among sharks, and the 

 modification of the posterior edges of die pelvic 

 (ins into rodlike semitubular claspers (the copula- 

 ton organs) distinguishes males and females at a 

 glance. Some bear "living" young, ready for 

 independent existence; others lay eg^s. 



» Berg, Com. tctlol, Comm. Mus N'ac. Buenos &irea, ral. I. No. 1. 1898, 



p. hi 



-!. 



KEY TO GULF OF MAINE SKATES AND RAYS 



The front, (if the head bears a pair of separate, ear-like fins, extending forward 



The front of head does not bear a pair of separate ear-like fins extend inn forward 



There is a large triangular caudal fin, as well as two well developed dorsal fins on the tail. 



There is no distinct caudal fin; the dorsal fins, if any, arc very small . . 



No long dorsal spine on tail - - 



There is a long saw-edged dorsal spine (or spines) on the tail 



The upper surface of the disc is marked with conspicuous black rosettes . . 



The markings on the upper surface of the disc are not in the form of black rosettes. 



Devil ray. p. 77 



...2 



Torpedo, p. 58 



..3 



Common skale< 4 



,.11 



leopard skate, p. 66 



...5 



There are no conspicuous thorns along the mid-dorsal zone of disc between the spiracle-; ami the base of tail; the lower 



surface of disc is marked with black dots or dashes, marking the openings of the mucous pores. 



Barndoor skate, medium sized and large specimens, p. 61 

 There are one or more rows of conspicuous thorns along the mid-dorsal zone of disc rearward from the spiracles; the 



lower surface of disc is not marked witli black dots or dashes — 6 



There are no large thorns on the rear %-}', of tail . . - Smooth-tailed or Prickly skate, p. 70 



There are one or more rows of large thorns along the rear part of tail a< well as fan her forwar I along it__ . 7 



There are no large thorns on upper side of disc between the spiracles and I he level of axils of pectoral fins. 



Barndoor skate, very small specimens, p. 61 



The uppersideofdi.se, rearward from spiracles, has more or fewer hour l horns . 8 



The thorns of the midrow on the tail are much larger and more conspicuous than any other thorns on the tail, and not 



more than 9 or 10 in number Thorny skate, p. 72 



No one row of thorns along the tail is much larger or more conspicuous than the other thorns on the tail; there are at 



least 15 thorns in each of the rows along tail — 'J 



210941—53 5 



