172 University of California Publications. [Zoology 



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Family DASYATID^. 

 20. Urolophus halleri Cooper. 



THE ROUND STING RAY. 



(Jordan and Evermann, 1896, I, p. 80.) 

 The commonest sting ray of San Diego Bay. They are a great 

 pest to fishermen working in the bay, as they cut nets and lines 

 and nmch time is wasted in disentangling them from seines. 

 Fishermen never fail to kill them when caught, though their num- 

 bers doubtless make them one of the most valuable scavengers. 



A couple of embryos nearly three inches long taken from the 

 oviduct of an adult, have a conspicuous flap extending back from 

 the eye and the upper edge of the spiracle and ending in a rather 

 long free point behind. 



Some specimens are dark brown on the entire upper surface, 

 profusely spotted with clear-cut, round, light yellow dots, smaller 

 than a pin head, which are indistinctly ringed with brown darker 

 than the body color. Other specimens (the more usual colora- 

 tion) have the spots more indistinct, blended, and many of them 

 run together, making short reticulated nuirks. Still other speci- 

 mens are uniform slaty brown above, without a trace of spots. 

 Sometimes specimens have large, light, blended spots, as large in 

 diameter as the combined length of the eye and spiracle, and with 

 or without the small spots. Ventral surface white medially, grow- 

 ing orange or red towards edge of fins and on caudal peduncle. 

 Extreme edge of fins and lower surface of caudal peduncle some- 

 times light brown, and with or Avithout small, light spots. Known 

 . from Santa Barbara (Jordan and Gilbert, 1880, p. 457) south- 

 ward probably to Panama (Gilbert and Starks, 1904, p. 15). 



21. Dasyatis dipterura Jordan aud Gilbert. 



THE RAT-TAILED RAY. 



(Jordan and Evermann, 1896, I, p. 85.) 

 This species is not uncommon, though taken by us less fre- 

 quently than any other of the sting rays. The smaller specimens 

 are perfectly smooth; a specimen 29 inches in length had four 



