738 PLAGIOSTOMATA— BATOIDEI. 



In the cold season, as about October, these fish are frequently perceived springing out of the water for 

 some distance. They devour large quantities of small fish, Crustacea, molluscs, &c. 



Habitat. — Red Sea, seas and estuaries of India to the Malay Archipelago, and China, also the Cape of 

 Good Hope. The immature are frequently captured in the back waters, and wounds from their caudal spines 

 are much dreaded. In one instance, an old man was admitted into the Civil Hospital in Cochin for mortification 

 of the arm, due to a wound inflicted by one of these fish, which he attempted to drag out of the sea into a 

 boat : it wound its tail round his arm, and dragged its spine through the muscles nearly dowp. to the bone. 

 They attain a large size, as 5 feet or more across the disk. 



3. Trygon marginatus. 



Blyth, Journal Asiatic Soc. of Bengal, 1860, p. 38 ; Dumeril, Hist. Nat. Poiss. i, p. 588. 



? Trygon atroeissimus, Blyth, 1. c. p. 39. 



Disk slightly broader than long, tail from 1/2 longer to nearly twice as long as the disk. The width 

 of the interorbital space equals the length of the snout. Tubercles sparsely set all over the upper surface, 

 but a little larger along the median line, where they appear like small limpets : an irregular row of pointed 

 tubercles on either side of the middle line of the back : tail tuberculated as far as its spine, but destitute of 

 any fin. Colours — gray above ; bufEy- white below, with a dark border, except in front. 



In all the examples examined by Blyth, the caudal spine had been removed, as is usually done by 

 fishermen. T. atroeissimus, is founded on some pieces of tails of a Trygon, in which the spine is present ; it 

 may be that the two species are identical. 



Habitat.- — -Hooghly at Calcutta. I examined one of the examples in which the disk was 16 inches 

 across and 15 long ; but Blyth says one specimen was 62, another 60, inches across the disk, and the tubercles 

 were extended on to the edge of the disk and even to its under surface. This would therefore appear to be 

 a result of age. 



3. Trygon Bleekeri, Plate CXCV, fig. 3. 



Blyth, Proc. Asi. Soc. of Bengal, 1860, p. 41 ; Dumeril, Hist. Nat. Poiss. i, p. 593 ; Giinther, Catal. 

 viii, p. 476. 



Tail from three to four times as long as the disk. Snout prolonged and pointed. Width of interorbital 

 space equal to 1/2 or 1/3 in the length of the snout anterior to the eye. A large round tubercle in the middle 

 of the back, and commonly three smaller triangularly disposed before it, and three similarly placed behind it. 

 Tubercles sometimes present along the upper surface of the tail to the caudal spine, from whence, in adults, 

 they are continued to its extremity. Colours — " Brown above and below, with a narrow white median 

 longitudinal patch on the abdomen." — Blyth. The example figured is brown above with margins of the disk 

 dark. 



Habitat. — Bengal. Blyth observes, length of one 25 inches to base of tail, the tail 72 inches : of another 

 16 and 56 inches. The example figured is 8 inches across the disk. 



4. Trygon walga, Plate CXCIV, fig. 3. 



Eaja, Russell, Fish. Vizag. i, p. 3, and Isacurrah tenhee, pi. iv, and Terikee shindraki, pi. v. 



? Baiafluviatilis, Ham. Buch. Pish. Ganges, p. 1. 



Trygon walga, Miiller and Henle, Plagios. p. 159, t. 50; Bleeker, Plagios. p. &7 ; Blyth, J. A. S. of Beng. 

 1860, p. 40 ; Dumeril, Hist. Nat. Poiss. i, p. 589 ; Giinther, Catal. viii, p. 476. 



Pastinaaa hremcauda and dorsalis, Swainson, Pishes, ii, p. 319. 



Trygon chindrakee, (Cuv.) Bleeker, Beng. p. 9. 



Trygon heterurus and polylepis, Bleeker, Plagios. pp. 67, 73 ; Dumeril, Hist. Nat. Poiss. i, pp. 590, 591 ; 

 Giinther, Catal. viii, p. 475 ; Klunz. Pische Roth. Meer. 1871, p. 680. 



Trygon dadong, Bleeker, Nat. Tyds. Ned. Ind. x, p. 356 ; Dumeril, 1. c. p. 691. 



Trygon imbricata, Cantor, Catal. Mai. Pish. p. 426 (? Bl. Schn.) : Blyth, J. A. S. of Beng. 1860, p. 40. 



Trygon immunis, Bennett, Life of Sir S. Rafiles, p. 694. 



Disk about as broad as long, with the snout pointed and acutely projecting, more so in some examples 

 than in others. Eyes smaller in the adult than in the young. Interorbital space concave. Teeth — small, 

 having a transverse elevated ridge along each. Dental lamina undulated. Fins — no cutaneous folds on the 

 tail, the length of which is rather longer than the disk. One or two (sometimes more) large serrated spines 

 on the tail at the commencement of its second third, between this and the base of the tail exists a median line 

 of about seven short spines. Scales — interorbital space, and for a varying width along the middle of the back 

 and also on the tail exist numerous fine tubercles which usually have no larger ones, but in some examples 

 there is one on the centre of the shoulder, in others a few more anterior to it. Neither the number, size, 

 character, nor extent of the distribution of the tubercles and spines depends on age or sex, adults even may 

 be without any of either. In one example (a male) the band of tubercles along the back is very narrow, a 

 row of large ones exists in the median line of the scapular region, and four along the back of the tail. This 



