390 



THE PLAGIOSTOMIA. 



Mouth waved. Eyes small; spiracles much larger. Ventrals short, subquad- 

 rangular. Tail nearly twice as long as the body, with a low fold or keel behind 

 the spine above and a deeper longer one below. Skin smooth. 



Back greenish to reddish brown ; dingy white below. Hardly distinct from 

 D. pastinacus, but said to attain larger size, with outlines of disk more convex. 



Mediterranean. 



Dasybatus violaceus. 



Trygon violacea Bonaparte, 1841, Icon. Ital. Fauna, Pesci, p. 551, pi. 71; Mulleb & Henle, 1841, 

 Plagios., p. 162, 200; Dumeril, 1865, Elasm., p. 602; GiiNTH., 1870, Cat. fishes Brit, mus., 8, 

 p. 477; MoREAu, 1881, Poiss. France, p. 449; Doderlein, 1885, Man. ittiol. Medit., 3, p. 226. 



Dasyatis {Pteroplaty trygon) violaceus Fowler, 1910, Proc. Acad. nat. sci. Phil., 62, p. 474. 



Rhomboid ; length of body about two thirds of the width of the disk ; snout 

 blunt, anterior margin almost a continuous curve, subtruncate; outer margins 

 like the anterior slightly convex; hinder angles blunted. Ventrals short rounded. 

 Tail about twice the length of the disk, slender, with a low fold behind the spine 

 above and a longer deeper one below. Skin smooth, with the exception of a 

 vertebral row of tubercles from the middle of the back, and a few scattered ones 

 on the shoulders and head. Young individuals quite smooth, very old ones 

 with more spines and tubercles. Mouth waved. Miiller and Henle found an 

 entire row of papillae, instead of five, behind the teeth of the lower jaw. 



Violaceous to dark brown above; light below. 



Allied to D. say possibly identical. 



Mediterranean Sea. 



Dasybatus longus. 

 Plate 32, fig. 3-4. 



Trygon longa Garman, 1880, Bull. M. C. Z., 6, p. 170. 

 Dasibatis longa Garman, 1882, Bull. 16, U. S. nat. mus., p. 66. 



Dasyatis longa Jord. & Everm., 1896, Bull. 47, U. S. nat. mus., p. 85; Gilbert & Starks, 1903, 

 Mem. Cal. acad. sci., 4, p. 17. 



Disk subquadrangular, about one sixth wider than long, anterior margins 

 straight meeting in a blunt angle at the end of the snout, outer angles rounded. 

 Mouth curved, with five papillae at the bottom. Ventrals rounded. A row of 

 small depressed and compressed tubercles behind the head on the shoulder girdle, 

 extended backward with age. Tail more than twice as long as the body, rough 

 with small spines, compressed behind the caudal spine, keeled above the com- 

 pressed portion, a long narrow fold below. Differs from D. latus and D. marinus 



