4:6 " THETIS " SCIENTIFIC RESULTS. 



DASYATIS, Rafinesqne. 



DASYATIS THETIDIS, sp.nov. 



Black Sting Ray. 



Dasyatis thetidis, Ogilby, MS. 



Stations 21, 22, 23, 58. 



" Disc subquadrangular rather more than one-fourth wider 

 than long. Anterior border sinuous, convex near the shghtly 

 protuberant snout and the rounded angle, concave between ; 

 posterior and inner borders conspicuously convex, the hinder 

 angle obtuse. Skin smooth, a row of strong, rounded or oval, 

 stellate tubercles along the median line of the back and tail, each 

 tubercle armed with a stout depressed spine directed backwards ; 

 scapular region with one or two similar tubercles. Mouth rather 

 feebly crescentic, its width two-fifths of the preoral length and 

 four-fifths of the distance between the anterior angles of the 

 nostrils; buccal papillae five, the outer pair small and remote 

 from the inner three. 



" Teeth arranged quincuncially, in 16 series in the upper and 21 

 in the lower jaw, the crown of each tooth hollowed mesially. 

 Hinder border of ventral fins feebly convex, the angles rounded. 

 Tail depressed before, cylindrical behind the spine, rounded and 

 keelless above, a low cutaneous expansion below, armed on all 

 sides with stout spines. 



" Dark olivaceous-brown, teeth flesh-coloured, with a median 

 transverse orange band. 



" This is the common ' Black Sting-Ray ' of Sydney, and is 

 probably the species spoken of by Dr. Giinther and his followers 

 as Trygon tuherculata. The length of the disc in the specimen 

 described was 1,000, its width 1,275 millimeters; the tail was 

 broken ofi" some distance behind the spine." 



The specimen a'bove described was one of three, taken in 

 consecutive hauls in Newcastle Bight, the depths ranging from 16 

 to 40 fathoms. These rays weighed respectively 1601b., 2201b., 

 and 1401b. A fourth example weighing 1801b. was taken south 

 of Port Hacking in 28-42 fathoms. The ray above described was 

 forwarded by me to the Museum, but having Vjeen much damaged in 

 transit was not preserved. Mr. J. D. Ogilby, who happened to be 

 in the institution at the time it was received, made the foregoing 

 description at the request of the Curator, and has since handed 

 it to me for publication. 



A young Dasyatis, obtained likewise at Station 22 and pre- 

 served, agrees in all essential points with the description. In 



