444 



THE PLAGIOSTOMIA. 



Teeth in nine rows on the upper jaw; seven on the lower 



median row nearly three times and next rows one and one half times as wide 

 as long, second from median narrow, outer narrowest 



marginata (page 445) 

 median row and second on each side of it 3 times as wide as long, narrower 

 than row at each side of median . . adspersa (page 447) 

 median three rows 5-7 times as wide as long, others narrower 



jussieui (page 447) 

 median row 8 times as wide as long, next row 4 times jayakari (page 448) 

 median three rows and outermost rows 2-3 times as wide as long 



peli (page 448) 

 Teeth on upper jaw in 15 rows, on lower jaw 19, abnormal polyodon (page 448) 

 Teeth on lower jaw in 14 rows, abnormal . . . encenadae (page 448) 



Rhinoptera quadriloba. 

 Plate 37, fig. 1-5. 



Raia quadriloba Lesueur, 1817, Journ. Acad. nat. sci. Phil., 1, p. 44, pi. 



Myliobatis quadriloba Cuv., 1829, Reg. anim., 2, p. 401. 



Rhinoptera quadriloba Voigt, 1832, Thierreich, 2, p. 525; DeKay, 1842, N. Y. fish., p. 375, pi. 66, f. 



217; Dumeril, 1865, Elasm., p. 648; Gunth., 1870, Cat. fishes Brit, mus., 8, p. 494; Jordan & 



Gilbert, 1883, Bull. 16, U. S. nat. mus., p. 51. 

 Rhinoptera bonasus Jord. & Everm., 1896, Bull. 47, U. S. nat. mus., p. 90. 



Disk broad, length including ventrals and head about equal to seven tenths 



of the width. Head short, as broad as long, deeply indented in front of the 



fontanel and between the rostral fins. Teeth in seven rows: — median upper 



about five times as wide as long, next row half and second row one fourth as wide 



as the median, outer row as wide as long. Median lower four fifths as wide as 



the upper, outward rows decreasing in width like the upper. The pavement is 



less convex transversely than that of R. lalandii, and is more arched than that 



of R. jussieui. Pectorals longer than wide, outer angle acute, tip slightly 



falciform, hind angle blunt. Ventrals narrow, more than half as wide as long, 



hind margin convex, slightly oblique, inward rays somewhat longer. Dorsal 



origin little behind ends of ventral bases, upper margin straight, upper angle 



blunted; hind angle produced in a sharp point not extending quite as far back 



as the ends of the ventral fins. Skin smooth. Tail less than twice as long 

 as the disk. 



The specimen described was secured by Mr. Samuel Powel, at Newport, 



