452 THE PLAGIOSTOMIA. 



laterally at a short distance from the angle of the mouth ; body and tail smooth ; 

 the distance between the mouth and the dorsal fin is one half of the greatest 

 width of the body ; tail more than twice as long as the disk ; upper parts uniform 

 brown; top of the dorsal fin white. Greatest width of the disk fifteen inches; 

 distance between the front margin of the head and dorsal fin seven and one third 

 inches. 



Mysol Island. 



Anterior margin of snout and front margins of pectorals nearly straight; 

 hind margins of disk concave, angles acute. Dorsal fin between the ventrals, 

 but base and end extending little farther back than in those fins. 



MOBULA KUHLII. 



Cephaloptera kuhlii Muli.er & Henle, 1841, Plagios., p. 1S5, pi. 59, f. 1; Bleeker, 1857, Act. Soo. sci. 



Ind. Neerl., 3, p. 6; 1859, ibid., 6, p. 214; Dumeril, 1865, Elasm., p. 654. 

 Dicerobatis kuhlii Gunth.. 1870, Cat. fishes Brit, mus., 8, p. 497; Day, 1878, Ind. fishes, p. 745. 

 Dicerobalis thurstoni Lloyd, 1908, Rec. Ind., mus., 2, p. 179, fig. 3, pi. 4, f. 2. 



Disk about twice as wide as long; anterior margins of the pectorals slightly 

 convex, posterior concave, angles acute, narrowly rounded at the apex. Nasal 

 valves confluent into a broad flap free at the nostrils and to a very slight extent 

 in front of the teeth. Teeth bands occupying about two thirds of the width of 

 the jaws, not extending to the angles of the mouth. As the teeth first appear, 

 in the embryo, they are minute and widely separated; they resemble flattened 

 tubercles; but as the later teeth appear in the same rows they enlarge rapidly, 

 until broader than long and teeth and rows are in contact, tessellated. In cases 

 it appears as if teeth had united thus decreasing the number of rows. The 

 change from the minute, round, separate teeth to the broad teeth in close rows 

 is made in a row of eight or ten teeth, all stages to be seen together on a single 

 jaw. The appearance resembles that figured on Plates 48 and 49 for the be- 

 ginnings of the rows of teeth on Rhinoptera, Myliobatus, and Aetobatis, though 

 much more extensive; the resemblance is particularly noticeable in a comparison 

 with fig. 1 of Plate 48, Rhinoptera jussieui. The specimen described, I65 inches 

 wide, has teeth in t| rows. Tail little longer than the disk, without a spine. 



Origin of dorsal fin above end of vent, one fourth of the base above the bases 

 of the ventrals, end of the base as far back as the ends of the same fins. Skin 

 smooth, in young. 



Dark brown above; white beneath. 



Indian Ocean; East Indies; Japan. 



