102 " ENDEAVOUR " SCIENTIFIC RESULTS. 



Family DASYATID^. 

 Genus Dasyatis, Rafinesque. 



Dasyatis brevicaudatus, Hutton. 



(Plate XV., fig. 1 ; Plate XVII., fig. 1.) 



Trygon brevicaudata, Hutton, Ann. Mag. Nat. Hist. (4), xvi., 

 1875, p. 317, and Trans. N.Z. Inst., viii., 1876, p. 216. 



Dasybatus brevicaudatus, Waite, Rec. Cantb. Mus., i., pt. 2, 

 1909, p. 151, pi. xxii. 



Disc sub quadrangular, wider than long, the length from the 

 tip of the snout to the posterior angle of the pectorals 1-19 in 

 the breadth. Upper and lower surfaces perfectly smooth, 

 without traces of spines or tubercles. The snout is a little 

 prominent. Anterior margin indistinctly sinuous, at first a 

 little convex, then very slightly concave ; outer angle distinct 

 but rounded. Postero-lateral borders of disc a little convex, 

 nearly straight, and forming an obtuse angle with the inner 

 margins. Margins of ventrals convex, the angles somewhat 

 rounded ; the inner border may be cut into one or two 

 angular lobes. 



Tail depressed before, cylindrical behind, the spine, its 

 length 1-06 in that of the disc. The basal portion is smooth, 

 but a few small scattered spines are present on the sides at 

 about the level of the insertion of the spine, and they become 

 more numerous as they approach the tip ; the terminal part, 

 beyond the lower cutaneous lobe, is uniformly rough with 

 small spiniform tubercles. Spine depressed and grooved, the 

 margins coarsely serrated, 0-65 longer than the preoral length. 

 Lower cutaneous lobe commencing a little behind the inser- 

 tion of the spine, and ending a little beyond its tip ; its 

 greatest height is at the end of the anterior third of its length, 

 but it does not equal the depth of the tail above it. 



Eyes very small, placed nearer together than the spiracles, 

 4-83 in the bony interorbital space, which is 1-53 in the preoral 

 length. Spiracles very large, longer than broad, their length 

 1-57 in the interorbital width ; the upper margin is straight, 

 the outer circular. 



The anterior part of the lower surface is closety pitted with 

 minute pores. The space separating the nostrils is a little less 

 than their distance from the tip of the snout. Outer angles 

 of the intra-nasal lobe acute ; the hinder margin bears a 

 narrow papillose flap, which forms two small lobes near the 

 median line. Width of the mouth slightly less than two- 

 thirds of the preoral length. Lateral teeth tubercular, the 



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