382 THE PLAGIOSTOMIA. 



tail twice length of disk; disk rounded, little wider than long 



tubercles one on each shoulder . . schmardae (page 386) 



tail one and a half lengths of disk; disk wide, angles rounded. 



tubercles a group on each shoulder; squamae like shagreen of 

 sharks torrei (page 386) 



Dasybatus marinus. 

 Plate 33, fig. 1-2; Plate 44, fig. 7 (brain); Plate 53, fig. 5 (pelvis). 



Pastinaca aspera Belon, 1553, Aquat., p. 94; Willughby, 1686, Pise, p. 68, pi. D5, f. 3; Moreau, 



1891, Poiss. France Suppl., p. 12. 

 Pastinaca marina Columna, 1592, Phytob., ed. 1744, p. 105, pi. 28. 



Dasybatus marinus Klein, 1742, Hist. pise, miss., 3, p. 35; 1775, Neuer schaupl., 1, p. 992. 

 Raia cenlroura Mitch., 1815, N. Y. lit. & philos. trans., 1, p. 479; DeKay, 1842, N. Y. fish., p. 373 note. 

 Trygon aspera Cuv., 1817, Reg. anim., 2, p. 36. 

 Trygon gesneri Cuv., 1829, Reg. anim., 2, 400. 

 Trygon thalassia Muller & Henle, 1841, Plagios., p. 161; Gray, 1851, Chondropterygii, p. 118; Du- 



MERiL, 1865, Elasm., p. 596; Gunth., 1870, Cat. fishes Brit, mus., 8, p. 477; Hector, 1872, Fishes of 



New Zealand, p. 85; Canestrini, 1872, Ital. pesci, p. 59; Doderlein, 1885, Man. ittiol. Medit., 3, 



p. 228. 

 Trigon centroura Linsley, 1844, Amer. journ. sci., 47, p. 78. 

 Pastinaca acanthura Gray, 1854, Gron. syst., p. 12. 



Trygon ukpam Smith, 1859, Proc. Roy. soc. Edinb., p. 64; Gunth., 1870, Cat. fishes Brit, mus., 8, p. 480. 

 Pastinaca hastata Storer, 1867, Mass. fishes, p. 268, pi. 39, f . 3. 

 Dasyatis centrums Jord. & Gilbert, 1882, Bull. 16, U. S. nat. mus., p. 47; Jord. & Everm., 1896, 



Bull. 47, U. S. nat. mus., p. 83. 

 Dasibatis centrura Garman, 1882, Bull. 16, U. S. nat. mus., p. 67. 



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

 forming a blunt angle at the end of the snout, posterior margins nearly straight, 

 hinder angles blunt. Mouth arched forward, with five papillae. Teeth blunt, 

 smooth, in quincunx, in rows, in a specimen 43i inches in width. 



Ventrals truncate, angles rounded. Tail more than twice as long as the disk, 

 compressed distally, rounded above, with a dermal fold below from the base of 

 the spine backward, rough on all sides with broad based stellate to round 

 tubercles each with a sharp conical cusp. Young individuals smooth; as they 

 grow scattered tubercles appear on the middle and hind part of the back and 

 on the top and sides of the tail; very old ones have the middle of the back 

 and the top and sides of the tail closely mailed with small flattened tubercles 

 among which are the larger ones. Readily distinguished from its nearest allies 

 in the Atlantic by the tubercles and ihe absence of a supracaudal fold. 



Atlantic and the Mediterranean Sea. 



