676 PLAGIOSTOMATA OF THE PACIFIC, 



Two curtain-like flaps overlap the lateral labial folds, which are 

 distinct when the mouth is open ; the lower border of the labial 

 flaps is slightly notched. The teeth-plates of the upper jaw are 

 nearly twice as wide as the lower. (48 mm. the upper, 27 mm. the 

 lower.) These plates consist of many longitudinal rows of teeth, 

 of which the middle ones are largest. 



On the back of the mouth there are rows of papillae on the 

 palate, seven in the first row and four in the second ; there are 

 similar but smaller papillae on the sides of the teeth of the 

 lower jaw. (Fig- 4.) 



The gill openings are of uniform size, but the distance between 

 the two anterior is nearly double that between the posterior. The 

 claspers are relatively small and cylindrical. 



3. DiSCOBATIS MARGINIPINNIS. 



This Ray was taken at Sorry or Wild Island, one of a group of 

 islands surrounding the Nares Harboui", on the north-west coast of 

 the large Admiralty Islands, during the same expedition as that in 

 which the Myliohatia just described was taken, and like it, no 

 specimen has been preserved. However, from drawings made on 

 the spot, a tolerably accurate diagnosis can be made out. It is 

 evidently of the family Trygonidcti, and belongs to that section of 

 them, which is without a spine on the tail, but it difiers so much 

 from the known genera of that section as to necessitate placing it 

 in a new genus with the following characters. 

 DiscoBATis. Nov. gen. 



Tail shorter than the disk, cylindrical, without fin or spine, 

 thick at the base and tapering to the apex. Disc circular. Body 

 quite smooth, ventral fins without notch. Teeth small and closely 

 impacted as in the Trygonidse generally. 



DiSCOBATIS MARGINIPINNIS. JST. Sp. 



PI. XLYI. Fig. 7-15. 

 Upper surface, light brown with blue spots, irregularly 

 distributed. Large spiracles (Fig. 9). Iris yellow, flap of the 

 same yellow also, but with a dark margin. Under surface white, 



