378 THE PLAGIOSTOMIA. 



Uniform brownish in young; older with scattered spots of yellowish on the 

 posterior part of the disk and with narrowed yellowish cross-bands on the tail; 

 very old ones greyish brown. A very close ally, possibly a variety, of D. uarnak. 



India; East Indies; Samoa; Zanzibar. 



Dasybatus alcockii. 



Trygon alcockii Annandale, 1909, Mem. Ind. mus., 2, p. 27, f. 3. 



Disk broader than long; snout pointed, its length two ninths of that of the 

 disk, greater than the width between the orbits. Mouth small, waved, with four 

 papillae at the bottom. Skin tough; scales flat, more or less rounded. Tail 

 slightly depressed, not twice as long as the disk, without cutaneous folds, with a 

 serrated spine. 



Dark olive-brown, with small obscure paler spots scattered over the disk 

 and base of the tail; edges of fins purplish; beneath whitish. Off the coast of 

 Orissa, India. 



Apparently a variety of D. uarnak. 



Dasybatus jenkinsii. 



Trygon . jenkinsii Annandale, 1909, Mem. Ind. mus,, 2, p. 28, f. 4. 



Disk broader than long, outer angles rounded; snout pointed, length two 

 sevenths to one fourth of that of the disk. Mouth undulated with four papillae. 

 Head, middle of back, and top of tail with a pavement of small flat rounded 

 scales, bluntly spinous on the tail. Enlarged spines with depressed crowns in 

 irregular series above the vertebrae. Tail not much longer than the disk, with- 

 out cutaneous folds, with a serrated spine. 



Back reddish olive, without definite markings; tail greyish; lower surfaces 

 white. 



The type, a male, from which the description was taken measured 103.75 

 cm. across the disk ; it was caught off the Ganjam Coast, India. 



Probably a variety of D. uarnak. 



Dasybatus marginatus. 



Trygon marginatus Blyth, 1860, Journ. Asiat. soc. Bengal, 29, p. 38; Day, 1878, Ind. fishes, p. 738; 

 Annandale, 1909, Mem. Ind. mus., 2, p. 30, f. 5, pi. 3, f . 11. 



Disk broader than long, outer angles narrowly rounded, snout blunt. Eyes 

 small. Mouth rather small, waved, with two papillae, near the angles. Head 

 and middle of back with closely set rounded depressed denticles more or less 



