TORPEDINID^. — XV. 21 



20. RAJA (Artedi) Linnaeus. (Raia or Raja, the Latin name.) 



a. Middle line of back and tail behind shoulders, unarmed in adult, with a row 

 of spines in young; outline of disk before spiracles obtuse, without 

 acute angle at tip of snout. 



b. Kows of teeth about |^. 



25. R. erinacea Mitchill. Common Skate. Tobacco-Box. 



Spines largest on front of pectorals ; smaller ones on head, back, 

 and shoulder girdle. Light brown, with round dark spots. L. 1^ 

 feet. Smallest and commonest of our skates, from Va. northward. 

 (Lat., hedge-hog.) 

 bb. Rows of teeth about -iS.. 



26. R. ocellata Mitchill. Big Skate. Similar to preceding, 

 but much larger, and with additional rows of spines along the back 

 and on sides of tail. Light brown, with dark spots ; usually a large 

 white ocellus with a dark centre on P. behind. L. 3 feet. Mass. N. 



aa. Middle line of back and tail with a row of spines at all ages; outline of 

 disk before spiracles forming a more or less marked angle at tip of snout. 



c. Angle at tip of snout short, obtuse; teeth 4fi.; body and tail with 



strong spines with broad stellate bases. 



27. R. radiata Donovan. A median dorsal row of large spines 

 or bucklers ; others about head. L. 1^ to 2 feet. N. Atl. ; rather 

 rare, S. to Cape Cod. (Eu.) 



cc. Angle at tip of snout acute, moderatelj' long; teeth 50 j jk, coarse spines 

 or bucklers. 



28. R. eglanteria Lacepede. Prickles small and sharp ; a large 

 spine on each shoulder. Brown, with darker bars and blotches. 

 L. 2 feet. Cape Cod southward ; not common. (^Eglantine, brier- 

 rose.) 



ccc. Angle at tip of snout much produced, blunt; teeth lA, 



29. R. laevis Mitchill. Barn-door Skate. Spines of body 

 very few and small, on head and back ; a row of larger ones on 

 median line of tail ; female rougher, as is usual among rays ; snout 

 very long, somewhat spatulate. Color brownish, with paler spots 

 mostly ringed with darker. L. 4 feet. Va. N. ; not rare. (Lat. 

 smooth.) 



Family XV. TORPEDINID^. (The Electric Rays.) 

 Trunk broad and smooth, the tail short and thick, with rayed 

 caudal and usually two rayed dorsals, the first over or behind ven- 

 trals ; a large electric organ made up of hexagonal tubes, between 

 head and pectorals. Genera 6, species 15, found in most warm 

 seas ; noted for their power of giving electric shocks. 



a. Dorsal fins two ; ventrals separate ; spiracle placed nearly an eye's diameter 

 behind eye ToiU'tDo, 21. 



