The Spotted Eagle Ray. 



■u 



the third 5 inches, and the fourth is 63^^ inches. The base of the tail as 

 far backward as the tip of the second spine is triangular in cross-section. 

 Behind that it is rectangular with the top and bottom planes slightly bowed 

 or arched outward. The tails of Mr. Coles's huge specimens of 19 12 (see 

 page 268) each bore four spines. These are shown for one specimen in 

 figure 9, plate v. 



The data given above for the writer's own specimens are from Beaufort 

 rays. Now there will be given similar data for Key West fish taken in 1913. 

 Ray No. i was 2^ feet wide, 2 feet Y2 inch long, and had a tail measuring 

 3 feet \yi inches. Its anterior spine was i^, its posterior 1% inches long. 



Ray No. 11, 2^ feet wide, i foot 11 inches long, had a tail 3 feet 8}/^ 

 inches in length. Its three spines were respectively i^, 2, and i^ inches 

 long. No. Ill was 2 feet 10 inches in width, 2 feet in length, with a tail 

 measuring 5 feet. Its three spines going from front to back were i J^ inches, 

 2^, and ij^ inches. 



Key West ray No. iv was much the finest specimen I have ever had, 

 approximating in size Coles's giant specimens from Cape Lookout. Its 

 width from tip to tip of pectorals was 5 feet 2 inches, length from tip of 

 snout to end of ventrals 3^ feet, length of tail only 6 feet 10 inches, length 

 all over 9^ feet, weight 120 pounds. Like my best Beaufort specimen, it 

 had four spines, but the front spine, torn loose and hanging by a shred of 

 skin, measured only 2 inches; the others were perfectly nor- 

 mal and measured 4^, 5, and 4^/^ inches long. 



Various authors, notably Jordan and Evermann (1898), 

 give as a specific character of Aetobatus narinari that the 

 second spine is twice the length of the first. Where there 

 are more than two, and especially when there are as many 

 as four or five spines, there is a fairly regular gradation in 

 size. Coles (19 10) says that if one spine is torn out the 

 one immediately in front grows larger to take its place. 

 My own observations are confirmatory of this point. 



It should be noted here, however, that, perhaps as the 

 result of this multiple spine formation, the largest spine 

 of the spotted ray is uniformly smaller than that in a 

 Stingaree of the same size. The ordinary sting rays, 

 however, not infrequently have two spines, in which case 

 generally, if not always, the anterior sting is the larger. 

 This is true of the several dried tails in the possession of 

 the writer, one of which has four stings. 



Attention is called just here to an interesting dift'erence 

 in the root structure of the spines of these two kinds of 

 rays, which structure has never, so far as the writer 

 knows, been recorded. Text-figure 5 is a photograph of 

 two of these spines : Fig. A represents that of Dasyatis say, Fig. B that of 

 Aetobatus narinari. The sting of Dasyatis say which is torn off with diffi- 



19 



Text-fig. 5. 



