290 Papers from the Marine Biological Laboratory at Tortugas. 



they were perfectly identical. The generic characters of the teeth given in 

 the "Introduction" (1880) are identical with those noted above. 



Klunzinger (1871) thus redescribes the jaw structures of the Spotted Ray 

 of the Red Sea: 



Upper jaw truncated and broader, but much shorter than the angularly rounded lower 

 jaw which projects from the mouth. The tooth lamellae of the under jaw form a sometimes 

 pointed, sometimes blunt arched angle in the middle. 



In his "Fishes of India" (1878) Day tells us that the teeth of the lower 

 jaw of A. narinari may be angularly bent or nearly straight, thus con- 

 firming Gunther. He adds, however, that the teeth are greenish yellow. 

 As stated elsewhere the teeth of all Beaufort and Key West specimens 

 examined were white. 



Dean (1895), in his " Fishes, Living and Fossil," on page 24, gives a figure 

 (29) with the following legend : ' ' Dental plates of jawof sting-ray, Trygon ( ?) ." 

 In the text, after referring to the pavement teeth of an ordinary eagle ray 

 (which he also figures), he continues: 



A still more perfect fusion of the dental elements 

 occurs in a ray, closely akin to Myliohatis; all lateral ele- 

 ments have been fused, but their metameral sequence 

 has been retained (figure 29). 



His figure is plainly that of the jaw of an 

 Aetohatus but unfortunately there is no indi- 

 cation of its source. The commonly accepted 

 idea is that the lateral teeth have disappeared 

 (probably have failed to develop) and that the 

 central teeth have become elongated and 

 arched outwardly. Attention is again called 

 here to Gunther's (1870) series of jaws showing 

 this. Dean's figure is reproduced here as 

 text-figure 13. 



Jordan and Evermann, in their "Fishes of 

 North and Middle America" (1896) speak of 

 the teeth of the genus as broad, flat, in a single 

 series, upper straight, lower curved, the lower 

 jaw projecting; while for the species they say; 

 straight or more or less angularly bent." 



13 



14 



Text-fig. 13. — Dental plate of 

 Trygon{?), after Dean. 



Text-fig. 14. — Teeth of A. nari- 

 nari, from Beaufort, North 

 Carolina. 



'Teeth of the lower jaw 

 Of an Hawaiian specimen, Jen- 

 kins (1904) reports the lower teeth to be obtusely angled forward with about 

 five projecting beyond the edge of the upper jaw. 

 Miranda Ribeiro (1907) thus speaks of the teeth: 



Mouth inferior, with plates of straight prismatic pavement-shaped teeth arranged 

 transversely in parallel rows; truncate in the upper jaw, in the lower the prisms at times 

 folded over to an obtuse angle with points to the front; the plate formed by che latter projects 

 considerably beyond the upper jaw and shows itself over the lower lip. 



Compare with this description figures 22 and 23, plate ix. Annandale 

 (1910) finds that the teeth of Indian specimens are transverse and not 

 angularly pointed in the lower jaw. 



