UROBATIS HALLERI. 403 



and in cases the brown contains transverse cloudings or indefinite bands on body 

 and tail. The specimen figured on Plate 29 is one of a number taken at Progreso, 

 Yucatan, by Dr. L. J. Cole. It represents a variety of U. sloani, rather than a 

 distinct species. 



Urobatis nebulosus. 



Urolophus nebulosus Garman, 1885, Proc. U. S. nat. mus., 8, p. 41; Jord. & Everm., 1896, Bull. 47, U. S. 

 nat. mus., p. 80. 



Disk subround resembhng that of U. halleri but differing from that species 

 in being rough with asperities over the posterior portion of the abdomen. No 

 median series of tubercles on back or tail. Three small papillae at the bottom 

 of the mouth. 



Entire length of the type 12, snout to ends of ventrals 7.5, snout to ends of 

 pectorals 7 and greatest width 7 inches. 



Clouded olivaceous brown on the back; whitish below. 



Colima, Mex. 



Urobatis halleri. 



Urolophus halleri Cooper, 1863, Proc. Cal. acad. sci., 3, p. 96; Jordan & Gilbert, 1882, Bull. 16, 

 U. S. nat. mus., p. 46; Jord. & Everm., 1896, Bull. 47, U. S. nat. mus., p. 80. 



Urolophus umbrifer Jord. & Starks, 1895, Proc. Cal. acad. sci., ser. 2, 5, p. 285; Jord. & Everm., 1900, 

 Bull. 47, U. S. nat. mus., p. 2752. 



Disk subcircular, front outhnes meeting at a very blunt angle at end of 

 snout. Nasal valves short, outer angles not produced, hind margin fringed. 

 Mouth small, waved, width nearly half the preoral length; teeth small, tessellate. 

 Eyes small, orbit about one fifth the length of the snout; spiracles larger. Ven- 

 trals short, broad, rounded. Tail near two thirds the length of the disk, fins 

 moderately deep, spine inserted in end of anterior half. Skin smooth. A close 

 ally of U. sloani but rounded. 



Specimen in hand 2O3 inches, tail from the pores 82, greatest width I25. 



In a lot of more than a hundred examples secured by Professor Louis Agassiz 

 at San Diego, California there is a considerable amount of individual variation in 

 colors. Most of the specimens are brown with small spots of yellow, very small 

 on some, larger on others, smaller toward the margins, thickly strewn over the 

 entire back and tail or occasionally absent from the middle of the disk. Less 

 numerous, perhaps, are those brown with vermiculations of yellow over the whole 

 back or only in the central portions. Some are more yellow than brown and on 

 some the brown is variously clouded. The back is usuallj^ darkest in the middle 

 and on the head; the fins are fighter near and on the margins; the tail is usually 

 not darker. 



