22. MYLIOBATIDJE. 49 



of tlie tail, covered by an armature composed of a very great number 

 of small bony tubercles. Along the median line an irregular series of 

 tubercles with the base enlarged, almost quadrilateral, the points directed 

 backward ; a tubercle on the shoulder girdle on each side of the median 

 line. Five papillae in the mouth. Jaws strongly arched. Very young, 

 almost smooth. Uniform brown. (DumeriL} Florida to Brazil. 



(Raia tuberculata Lacdpede, Hist. Poiss. ii, 103 : Trygon tiiberculata Dumdril, Elasrno- 

 braucb. 605: Trygon tiiberculata Giiatbcr, viii, 460.) 



65. D. saSjinaus (Le Sueur) Goodo & Bean. 



Disk oval-rhomboidal, scarcely longer than broad, the anterior bor- 

 ders lightly concave, united by rounded angles to the posterior borders, 

 which are longer and a little convex; snout projecting; tail twice as 

 long as the body; upper part of the head rough with small spines; on 

 the middle of the back a row of tubercles commencing behind the head 

 and prolonged on the base of the tail ; 5 buccal papilla? ; two spines on 

 each side of the shoulder girdle ; tail rough, with two short, low cutane- 

 ous folds; mouth strongly arched. Color uniform yellowish brown. 

 (DumeriL} " Distinguished from D. centrums by the shape of the disk, 

 the shape of the caudal spine, and the wing-like membranes on the 

 tail" (Goode in lit.). Perhaps '.deutical with the preceding. 



(Trygon sabina Le Sueur, Joum. Ac. Nat. Sci. Pbila. 1824, iv, 109: Trygon sabina 

 Duiudril, Hist. Nat. Poiss. i, 607: Trygon tuberculata Guntber, viii, 480, part.) 



FAMILY XXIL MYLIOBATIDJE. 

 (The Eagle Rays.) 



Disk broad; the pectoral fins not continued to the end of the snout, 

 but ceasing on the sides of the head and reappearing in front of the 

 snout as one or two fleshy protuberances (cephalic fins), which are sup- 

 ported by fin rays. Tail very long and slender, whip-like, with a single 

 dorsal fin near its root, behind which is usually a strong, retrorsely 

 serrated spine. Nasal valves forming a rectangular Hap, with the pos- 

 terior margin free, attached by a frenuni to the upper jaw. Skull less 

 depressed than usual among rays, its surface raised so that the eyes and 

 spiracles are lateral in position. Teeth hexangular, large, flat, tessel- 

 lated, the middle ones usually broader than the others. Ovoviviparous. 

 No differentiated spines on the pectorals in the males, the sexes being- 

 similar. Yentrals not emarginate. Genera 3 ; species about 20. Large 

 Bull. Nat. Mus. No. 16 4 



